DOS Times Vol 26 No 1

DVolume 26, No. 1 July-August 2020 SFor Private Ciruculation Only

Official Bulletin Magazine of

DELHI
OPHTHALMOLOGICAL
SOCIETY

Highlights

Genetics in Strabismic Disorders: a review of Current Knowledge
Advances in Strabismus
Retinopathy of Prematurity Screening
Paediatric Ocular Biometry and IOL Power Calculation

DOS Executive Members 2019-21

DOS Office Bearers

Dr. Subhash C Dadeya Dr. Pawan Goyal Dr. Namrata Sharma Dr. Hardeep Singh
President Vice President Secretary Joint Secretary

Dr. Jatinder S Bhalla Dr. Vinod Kumar Dr. Manav Deep Singh
Treasurer Editor Library Officer

Executive Members

Dr. Dewang Angmo Dr. Jatinder Bali Dr. Shantanu Gupta Dr. C. P. Khandelwal

Dr. Rahul Mayor Dr. Vipul Nayar Dr. Rajendra Prasad Dr. Kirti Singh

DOS Representative to AIOS Ex-Officio Members

Dr. Jeewan S. Titiyal Dr. M. Vanathi Dr. Rakesh Mahajan Dr. Arun Baweja
www.dosonline.org/dos-times
02 DOS Times - Volume 26, Number 1, July-August 2020

Contents

Editorial 47 Management of Periocular and Orbital Vascular
Lesions in Children
05
50 “When all else fails” - Secondary Episcleral Plaque
President Desk Brachytherapy in Retinoblastoma
06
53 Retinopathy of Prematurity Screening
Guest Editorial Desk 57 Laser in Retinopathy of Prematurity - Lessons to
08 Spreading Sight and Stereopsis for Kids the
Learn
World Across: Pediatric Ophthalmology and 63 Paediatric Ocular Biometry and IOL Power
Strabismus-2021
10 As Pediatric Ophthalmologist - Have we Achieved Calculation
Enough? 65 Work up in Paediatric Cataract
12 Pediatric Ophthalmology: The Future is Now 69 Pearls in Pediatric Cataract
76 Update on Pediatric Cataract / The Conundrum of
Pediatric Ophthalmology
Pediatric Cataract
14 Genetics in Strabismic Disorders: a Review of Current 81 Pediatric Optic Neuritis: Current Concepts in
Knowledge
Diagnosis and Management
19 Advances in Strabismus
24 Motor and Sensory Tests in Strabismus Monthly Meeting Update
30 Management of Esotropia
36 Intermittent Divergent Strabismus - A Brief Review 93 Hard Cataract: Decrease and Conquer – Technique
42 Congenital Corneal Opacities with a Difference

Tearsheet

99 Work of a case of Squint

Volume 26 No. 1, July-August, 2020

Editor In Chief DOS Times Editorial Board
Namrata Sharma
Editorial Board National Board
Editor Dr. Parul Icchpujani
Prafulla Kumar Maharana Dr. Atul Kumar Dr. Ronnie George
Dr. Aniruddha Maiti Dr. Sushmita Kaushik
Assistant Editors Dr. Apporva Ayachit Dr. Gopal Pillai
Dr. Jitendra Jethani Dr. Usha Singh
Ritu Nagpal Sahil Agarwal Dr. Mita Joshi Dr. Subhendu Boral
Dr. P. Dutta Majumdar Dr. Meena Chakrabarti
Dr. Noopur Gupta Dr. Raksha Rao
Dr. Brijesh Kakkar Dr. Kumudini Verma
Dr. Digvijay Singh Dr. Rashmin Gandhi
Dr. Ritika Sachdev Dr. Siddharth Kesarwani
Dr. Dewang Angmo Dr. Chaitra Jayadev
Dr. Rebika Dr. Bibhuti P. Sinha
Dr. Saurabh Sawhney Dr. Amit Porwal
Dr. Reena Sharma Dr. Prashant Bawankule
Dr. Rajat Jain Dr. Arvind Kumar Morya
Dr. Jaya Gupta
Deepali Singhal Rahul Kumar Bafna Dr. Anita Ganger
Dr. Umang Mathur
Mohamed Ibrahime Asif Gunjan Saluja Dr. Neera Agarwal
Dr. Poonam Jain
Dr. Manisha Agarwal
Dr. Hardeep Singh
Dr. Anita Sethi
Dr. Tushar Agarwal
Dr. Rohit Saxena
Dr. Swati Phuljhele
Dr. Vivek Dave
Dr. Mohita Sharma
Dr. Rajesh Sinha
Dr. Ritu Arora
Dr. P.K. Pandey
Dr. H.K. Yaduvanshi
Dr. O.P. Anand

Sohini Mandal Prakhyat Roop

04 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Editorial

From the
Editor’s Desk

Respected Seniors and Dear Friends

“Strabismus” is one of the most challenging subspecialty in ophthalmology. The understanding
of various strabismic pathologies has tremendously increased over the past two decades both in
terms of their etiopathogenesis as well as their management. Increased application of imaging
and as well as its better understanding and use of pharmacotherapy have also contributed
significantly. It’s my privilege to share few thoughts on “Strabismic disorders” in this special
upcoming issue of DOS times on “Strabismus and Pediatric Ophthalmology”.

It’s not very uncommon to encounter patients with strabismic disorders in an ophthalmic Prof. (Dr.) Namrata Sharma
outpatient department. Prevalence of these disorders ranges from 0.5-5%. Besides causing
cosmetic blemish, these disorders result in disruption of normal binocular vision as well as (MD, DNB, MNAMS)
stereopsis. Timely identification and prompt correction is important to avoid lifelong visual
impairment. Ocular examination should ideally begin from the newborn period and continue Hony. General Secretary
up to all subsequent visits of the child. All newborns should be examined for ocular alignment Delhi Ophthalmological Society
besides looking for other structural abnormalities, known to result in visual problems. Vision
assessment beginning at birth has been endorsed by the American Academy of Paediatrics, Cornea, Cataract & Refractive Surgery Services
the American Association of Pediatric Ophthalmology and Strabismus, and the American Dr. R.P. Centre for Ophthalmic Sciences,
Academy of Ophthalmology. All children who are found to have an ocular abnormality or All India Institute of Medical Sciences (AIIMS)
who fail vision assessment should be referred to a pediatric ophthalmologist or an eye care New Delhi
specialist appropriately trained to treat pediatric patients.

Amblyopia is another important aspect which needs to be taken care of especially in children less than 7 years of age. Since the degree of visual
deficit is related to the age of onset of abnormal visual stimulation, visual screening should start very early on, during the sensitive period of
visual development. As the success of various therapies decreases with advancing age of the child, treatment in the form of appropriate optical
correction and occlusion/penalization therapy of the dominant eye should start within the sensitive period. Various Amblyopia Treatment
Studies conducted by PEDIG have focused on evaluating the effectiveness and duration of different treatment modalities for children as well
as adolescents. Their results have provided us an evidence-based treatment approach for treatment of children with amblyopia.

Overall the management of childhood strabismic disorders, needs early on evaluation by an experienced pediatric ophthalmologist and
initiation of age-based appropriate therapy. This special issue on “Strabismus and Pediatric Ophthalmology” focusses on learning of various
strabismic disorders, their treatment modalities starting from optical correction to pharmacotherapy and surgical procedures and utility
of imaging techniques, management of amblyopia in accordance with various amblyopia treatment studies, in a phased manner from
“beginning to advanced” approach.

Sincerely,

Prof. (Dr.) Namrata Sharma

(MD, DNB, MNAMS)

Hony. General Secretary
Delhi Ophthalmological Society

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 05

President’s Editorial

From the
President’s Desk

Respected Seniors and Dear Friends

Having spent most of my career studying and mastering the art of childhood eye diseases, it is my privilege
to share few thoughts on Childhood blindness in this special issue of the DOS times – On Strabismus and
Pediatric Ophthalmology. Although this subspecialty is as vast as ophthalmology itself, there are only a
handful of dedicated Pediatric Ophthalmologists. There is a lack of training opportunities in the field of
Strabismus and ophthalmology . Strabismus and Pediatric Ophthalmology was not a popular choice among
residents previously. Possible reasons could be lack of Infrastructure, trained mentors , supportive staff and
instruments. However, now there is a slight change in the trend and some in the younger generation are
opting this subspecialty by Choice.

Personally, I still feel as passionately about this field 25 years later as I did when I was a First year senior
resident and asked to join this specialty in the larger interest of Institution. Whatever little recognition that
I have is because of this Subspecialty only.

This issue is an assortment of cases, reviews and reports from across the world in paediatric ophthalmology

We expand the spectrum of this domain to include excellent write ups from the stalwarts of pediatric ophthalmology.

A recent World Health Organization (WHO) report has estimated that, across the world, 19 million children are visually impaired and 1.4
million among them are legally blind. One million of whom live in Asia. The prevalence ranges from 0.3/1000 children aged 0–15 years in
affluent countries to 1.5/1000 children in very poor communities. According to the National Program for Control of Blindness, the number
stands at 8 out of 10,000 for childhood blindness in India. India has the highest number of children with blindness

The major causes of blindness in children vary widely from region to region, being largely determined by socioeconomic development, and
the availability of primary health care and eye care services. Although the prevalence of blindness among children is about 10 times lower
than that among adults, childhood blindness remains a high priority because of the expected number of years to be lived in blindness .About
40% of the causes of childhood blindness are preventable or treatable. The causes of childhood blindness vary, but the main avoidable causes
are. • Cataract; • refractive errors • low vision, amblyopia • corneal scarring, glaucoma; • retinopathy of prematurity; and trauma .

1. Cataract remains the leading cause of blindness despite impressive advancements in surgical services. Blindness related to pediatric
cataract can be treated with early identification and appropriate management.

2. Refractive errors

Uncorrected refractive errors, which affect persons of all ages and ethnic groups, are the main cause of visual impairment in children.
The correction provided must be affordable, of good quality and culturally acceptable. The most frequently used options for correcting
refractive errors are: spectacles, the simplest, cheapest and most widely used method; contact lenses, which are not suitable for all
patients or environments; and corneal refractive surgery, which entails reshaping the cornea by laser.

3 Amblyopia: Amblyopia is the leading cause of decreased vision among children. Early diagnosis and treatment can help prevent long-
term problems associated with amblyopia. Making the Vision Certificate mandatory at the entry level of school (like Vaccination),
giving us a 100% chance to examine each and every child will help in early diagnosis and complete cure from amblyopia.

4. Vitamin A deficiency is an important cause of childhood blindness. Vitamin A supplementation, measles vaccination, and nutritional
advice can be helpful in preventing the childhood blindness due to corneal scarring

5. Retinopathy of Prematurity (ROP) is growing as an important cause of childhood blindness across the world. Developing an effective
screening program in collaboration with neonatologists, timely referral and prompt treatment are key factors for successful outcomes
in ROP

06 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

President’s Editorial

6. Congenital glaucoma is amongst the leading cause of childhood blindness. Blindness due to congenital glaucoma can be treated with
early identification and treatment.

7. Injuries: Every injury in children should be treated as an emergency. Many eyes can be saved, if treated on time.

8. Early diagnosis of strabismus is essential in preventing irreversible vision loss later in life. Strabismus treatment aims to improve visual
acuity, perception of depth, increase the patient’s self-esteem and its adaptation to social life.

As the causes of blindness in children differ from those in adults, different control measures are needed. Therefore a comprehensive eye care
system needs to be in place to cater to the needs of children with avoidable diseases and those with incurable blindness. Early detection and
prompt management are critical for success of programs targeting avoidable blindness in children.

I also take this opportunity to welcome you all to participate in upcoming academic programs of DOS . The upcoming winter DOS and I DOS
will focus on the global perspectives in Ophthalmology. On behalf of the Executive, it gives us great pleasure to invite you to participate in
these wonderful academic and fun filled International Conferences. To promote healthy teaching, surgical skill transfer, ethical conduct and
state of the art cutting edge information should be our purpose and ambition.

Last but not least, I must take this opportunity to express my utmost gratitude again to Our Dynamic Secretary Prof Namrata Sharma and
the editorial team and all the contributing experts for their enthusiastic support and for making this world-class special issue possible.

I would like to put on record contribution of each and every member for making DOS virtual conference a grand success.

I look forward to our continued association.

Wishing you Happy New year 2021

Sincerely yours,

Prof. Subhash Dadeya
President DOS

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 07

Guest Editorial

Guest
Editorial Desk

Spreading Sight and Stereopsis for Kids the World Across
Pediatric Ophthalmology and Strabismus-2021

Pediatric ophthalmology is a constantly evolvingfield, encompassing a plethora
of disorders affecting the child’s vision. Its scope is no longer limited to improving
visual acuity and cosmesis, but also aims at preserving and restoring binocularity,
providing functional improvement, and improving overall quality of life. While
most eye disorders treated in adulthood yield immediate restoration of vision, same
is not true in kids, as a disorder in childhood affects the development of his vision, his
personality, and his life in long lasting manner, some of which can never be reversed.
Owing to its lasting Disability Adjusted Life Year (DALY) loss1, early diagnosis and
management of pediatric eye disorders pay rich dividends in the long run, making
pediatric ophthalmology a very rewarding profession.

However, this subspecialty comes with a unique set of challenges. Since the patients Prof. Pradeep Sharma
are often uncooperative for detailed examination and unable to vocalise their MD, FAMS
concerns, a pediatric ophthalmologist should be skilled at picking up subtle findings.
The recipe for success suggested is OCIPE: Observation- Confirmation-Inference-
Planning-Execution. Special charts/instruments are required for testing visual functions in children. Often,
we depend on distant direct ophthalmoscopy to get an idea about media opacities, refractive errors, and ocular
deviations. Refraction must be performed under proper cycloplegia only- general anaesthesia may be necessary if
the child is extremely uncooperative. The ongoing Covid pandemic has brought us some additional challenges,
especially in dealing with children who require a personal touch and a more affectionate approach.

Firstly, due to the limited options for education and entertainment, use of e-gadgets among children is on the rise,
with increase in asthenopic symptoms, refractive errors, and ocular deviations. Second, many parents now prefer
virtual consultations to hospital visits for safety concerns. The pediatric ophthalmologist has thus had to acquire
new skillsfor examination through tele-consultation2. However, it is important for us to decide which patients will
benefit from virtual examination. Besides evaluation of adnexa, corneal reflexes and pupil, assessment of near and
distance visual acuity, refractive errors, ocular deviation, extraocular movements, and stereopsis are also possible
using mobile phone/tablet-based applications like Eye handbook, 9-gaze, and Eye Test Charts. But teleconsultation
for posterior segment disorders is still at its nascent stages, and virtual examination, diagnosis and follow up of
these cases in our set up is difficult. Artificial intelligence and smartphones may help us with this aspect in the
near future.

Lastly, with the UN predicting a baby boom during the pandemic, our patient population is set to rise!3,4

Pediatricians should have a fair idea about paediatric ocular emergencies. Early diagnosis and quick referral to a
pediatric ophthalmologist should be facilitated. The reverse is equally true. Pediatric ophthalmologists should
have a good knowledge of systemic and syndromic association of ophthalmic features for timely pediatric referral.

The aim of this issue is to update ophthalmologists regarding some common ocular disorders affecting the little
humans – childhood strabismus and its genetics, periocular and orbital vascular malformations, retinopathy of

08 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Guest Editorial

prematurity, congenital cataracts, retinoblastoma, corneal opacities and pediatric optic neuritis. We are getting to
know more about the neural mechanisms of visual development, binocular vision and ocular motility, conditions
like childhood nystagmus, complex ocular motility problems like DVD and CCDDs as well as infantile strabismus.
We need to keep abreast with these developments and the application of artificial intelligence, convoluted neural
networks in the diagnostic aspects of visual functions, posterior segment examination, detection of reading
disabilities,5 and in future, even management of the problems of binocular vision development.The use of dichoptic
therapy for amblyopia management, intra-arterial chemotherapy for retinoblastoma, intralesional sclerosant
injection for orbital and peri-ocular veno-lymphatic malformations, oral propranolol for capillary hemangioma,
intravitreal anti-VEGF agents for ROP,and gene therapy for Leber’s congenital amaurosis have been gaining
popularity in the recent past and are valuable additions to the armamentarium of a pediatric ophthalmologist.
With a new year in the offing, ushering the dawn of hope, after an unrelenting dark night of the ironical 2020, we
hope for better binocular vision that offers Sight, Stereopsis and Smiles: for our future citizens.
“Spreading sight and happiness,
For kids the world across,
Maintaining the stereopsis
And restoring the loss!”
References
1. Wadhwani M, Vashist P, Singh SS, Gupta V, Gupta N, Saxena R. Prevalence and causes of childhood blindness in India: A

systematic review. Indian Journal of Ophthalmology. 2020 Feb 1;68(2):311.
2. Bhaskaran K, Sharma P. Distancing? But still I-care: Tele-ophthalmology during COVID-19 era. Indian Journal of

Ophthalmology. 2020 Jul 1;68(7):1243.
3. The unwanted baby boom: Fallout from lack of family planning services -- scores of unintended pregnancies [Internet].

[cited 2020 Dec 14]. Available from: https://www.timesnownews.com/india/article/the-unwanted-baby-boom-fallout-from-
lack-of-family-planning-services-scores-of-unintended-pregnancies/590297.
4. UN expects a global baby boom led by India due to Covid-19 lockdowns [Internet]. Hindustan Times. 2020 [cited 2020
Dec 14]. Available from: https://www.hindustantimes.com/india-news/un-expects-a-global-baby-boom-led-by-india-due-to-
covid-19-lockdowns/story-uAQHkgyv3J9zNuBQG7cYWJ.html.
5. Reid JE, Eaton E. Artificial intelligence for pediatric ophthalmology. Current Opinion in Ophthalmology. 2019
Sep;30(5):337–46.

Prof. Pradeep Sharma MD, FAMS
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,
AIIMS, New Delhi, India.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 09

Guest Editorial

Guest
Editorial Desk

As Pediatric Ophthalmologist -
Have we Achieved Enough?

‘But I’ve promises to keep, and miles to go before I sleep.’

Strabismology branched out as a sub speciality as early as the 1960s in India.
Alongside Strabismology, orthoptics also grew as a separate specialisation. In those
days, orthoptics was an independently certified training programme in it’s own right,
as comparable to today’s optometry. Orthoptists played a pivotal role in assessment
and intervention of strabismus and amblyopia so much so that they dictated the
surgical plans, dosage and treatment course of these disorders. Strabismus surgeons
were confined to performing surgeries only. Over the next sixty years this picture
has gradually transformed, shifting the scales towards ophthalmologists. As
ophthalmologists delved into understanding, assessing and analysing strabismus; Dr. P. Vijayalakshmi

independently making decisions, orthoptics went into a gradual decline. This
left only a handful of expert Orthoptists today. As much as on ophthalmologist’s hold over the subspecialty is
important, an orthoptist’s contribution cannot be underestimated. I strongly feel that a good orthoptist not only
augments a pediatric ophthalmologist’s efficiency but also improves acceptance and compliance in parents and
patients. Under the aegis of the international orthoptics association, this speciality is on power with pediatric
ophthalmology association.

Another milestone to our subspecialty is the metamorphosis of ‘strabismology’ to ‘Pediatric Ophthalmology and
Strabismus’ in early 1980s. I can proudly say that I was instrumental in establishing the comprehensive subspecialty
of Pediatric Ophthalmology and Strabismus for the first time in India, in 1984. This subspecialty was unique in
the sense that, it provided a comprehensive approach to pediatric eye disorders under one umbrella. Unlike other
specialities which catered to ‘parts’ of the eye, Pediatric Ophthalmology included the child as a whole. Aravind Eye
Hospital, Madurai, started an eighteen month fellowship training programme in 1991 to expand knowledge and
capacity building in our subspecialty. With the involvement of ORBIS India, these trainings gained momentum
with the goal of expansion to over 50 locations in the country in 2002. Three tertiary care centres were identified in
India towards training pediatric ophthal teams, strengthening and setting up centres across the country. Though
there is no denying that we had made great progress, we still fall short of standard WHO requirements.

Over the years I’ve come to realise that young ophthalmologists shy away from this subspecialty because it’s sounds
so alien and appears more analytical. This myth can be broken by introducing the basic concepts, introduction to
paediatric ophthalmology and approach to childhood vision impairment in community ophthalmology in the
under graduate curriculum and subsequently incorporating clinical learning in residency training. The key is to
make the subject simpler and understandable. After all, what is more magical than the functioning of a coordinated
eye and brain in a developing child!

The Strabismus society of India was conceived well before other subspecialties had their societies. The society
convened biannually under the able guidance of pioneers in the field. Today it has grown into SPOSI, with
international recognition. As a society we stand proud of our achievements, but is that all we can do? There are
major areas which need attention. Take refractive error for example. They are still the largest cause of curable

10 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Guest Editorial

vision impairment. Unlike adults, uncorrected refractive error in children is complex leading to amblyopia, poor
academic performance, even school dropouts. Though both government and non-governmental organisations
have taken up this issue, it’s sporadic without a standard approach and consistent follow up. Beyond detecting
refractive errors and providing glasses it is important to create awareness, ensure compliance and incorporate
good visual hygiene practices at the community level. For a country as large as ours with 23% under 15 years, 3
to 6% are at risk of refractive errors. This percentage is bound to rise, thanks to COVID situation and increasing
digital screen time. I feel it is our responsibility as a society to build an acceptable, uniform and standardised
practice pattern and network efficiently with NGOs and the government to implement these activities.
Another important condition that I’d like to focus is children born or acquire profound visual impairment early
in life. A moment of truth here, have we done justice to these children? Have we provided them with the care that
they deserve? Sadly, most of us would answer in the negative. Nowadays with NICU care, we have more premature
babies surviving. However they are also more prone to systemic and ocular morbidities. Visual problems in these
children take a backseat and almost always the visual impairment is attributed to developmental delay. If we
as ophthalmologists, could guide parents and screen these children early, they wound benefit immensely from
early intervention. The field of pediatric rehabilitation has grown by leaps and bounds in the recent years. Digital
resources, advance technology and instruments have made functional vision assessments and rehabilitation
strategies way better for conditions like cerebral vision impairment. Early intervention plays an indispensable role
in rehabilitating visual capacities in these children and improving their quality of life. For this to be successful, a
good networking among ophthalmologists, neonatologists and pediatricians should be built. Every child at risk
of vision impairment, being treated or discharged from NICU needs a pediatric ophthalmology referral. This must
happen at the apex level with both societies understanding their responsibilities and working together to advocate
and implement practical guidelines.
I’d like to end by quoting our late founder Dr GV who rightly said, ‘much has been done, but there is still much
more to be done’.

Warm Regards,
Dr. P. Vijayalakshmi
Chief, Paediatric Ophthalmology & Strabismus Dept.
Aravind Eye Hospital,
No.1, Anna Nagar,
Madurai, India.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 11

Guest Editorial

Guest
Editorial Desk

Pediatric Ophthalmology: The Future is Now

Dear friends,

We all have heard the frequently mentioned adage that “A child’s eye is not a
small sized adult eye”. It is therefore apt that the essential role a specialist pediatric
ophthalmologist plays in evaluating and managing childhood eye disorders is now
the focus of attention all over the world including this issue of DOS Times. Pediatric
Ophthalmology is now a distinct sub-specialty in ophthalmology requiring skill
in examining a child as well as expertise and experience in managing important
disorders of childhood that can leave a child with poor vision in one or both eyes for
life without any possibility of restoring vision later in life.

The life of a pediatric ophthalmologist, never an easy one with challenges in getting Prof. Rohit Saxena
a proper history of the disease and examining a pre-verbal child, has been made
exponentially more difficult by the need for social distancing in these covid times. MD, PhD.

The AIOS Pediatric and Neuro-Ophthalmology Expert Group has taken out guidelines
for practice in the times of COVID-19 which should be followed to ensure the best and safest outcome for the
practitioner and patient without compromising the quality of care each child deserves.

The additional challenge that these covid times has thrown up is the unprecedented restrictions that have limited
movement, regular schooling and outdoor recreational activities resulting in many young adults and children
spending long hours on electronics devices for entertainment and online e-learning with restricted time outdoors.
An entire generation of children has been simultaneously exposed to the influence of cumulative, well-proven,
risk factors for myopia and oculomotor and accommodative dysfunctions. While the World Health Organization
recommends < 1 hour of screen time for children aged 1-5 years with significant limits for older children, home
based digital learning is no longer a supplementary activity but is now a necessity in everyday learning. The real
and present danger is that this may become the new normal even after the restrictions are reduced with home-
based learning programs delivered through screen based devices and teachers, parents and children accepting this
as appropriate teaching methods.

It is therefore critical that ophthalmologists increase parent awareness about the effects of indoor near work
and reduced outdoor time on the incidence and progression of myopia and other ocular disorders. Parents need
to understand the importance of inculcating healthy eye habits in the children during the pandemic related
restrictions and beyond. These should include frequent breaks from near work and limiting recreational screen
time. Advising the AAO promoted 20-20-20 rule may help them to remember that the child should take a 20-second
break from looking at a screen every 20 minutes and during the break, the child focuses on an object 20 feet away,
which relaxes the eye muscles.

A holistic home-based learning curriculum should be planned that encourages creative learning not just from
reading and study at home, but also include frequent breaks, indoor physical or household activities with
supervised safe outdoor activities with adequate social distancing. Health benefits of outdoor activities and an

12 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Guest Editorial

active lifestyle should not be stifled by COVID-19. It is of paramount importance that parents help their children
to develop healthy digital device habits with a daily schedule with time allotted for specific activities and setting
boundaries on when and where digital devices can be used. Parents have to be role models by reducing their own
digital device usage, spending more time with their children and engaging them in offline play and activities.
The future of our next generation is in our hands today. Unless we proactively engage them to inculcate
healthy lifestyle habits, we risk condemning an entire generation to risks and consequences of high myopia and
other oculomotor problems.
A Merry Christmas and a very happy and safe New Year to all.
Prof. Rohit Saxena MD, PhD.
Dr. Rajendra Prasad Centre for Ophthalmic Sciences,
All India Institute of Medical Sciences,
New Delhi, India.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 13

Subspeciality-Pediatric Ophthalmology

Genetics in Strabismic Disorders: a
Review of Current Knowledge

Deepesh Unni, Karthika Bhaskaran, Pradeep Sharma MD
Pediatric Ophthalmology, Strabismus, Neuroophthalmology and Oculoplasty Services, Dr. Rajendra Prasad Centre for Ophthalmic
Sciences, AIIMS, New Delhi, India.

Abstract: Genetic disorders continue to be an important cause of morbidity and mortality in the general population, even
as continuing research and newer techniques in gene sequencing and analysis play an important role in the screening, early
detection, counselling and treatment. Ophthalmic diseases like anterior segment dysgenesis, aniridia, microphthalmos, corneal
dystrophies, retinitis pigmentosa, Leber’s hereditary optic neuropathy, colour blindness, retinoblastoma fall under the spectrum
of disorders warranting genetic testing. There are certain diseases among the wide spectrum of strabismic disorders included
in Congenital cranial dysinnervation disorders (CCDDs) like Congenital fibrosis of extraocular muscles (CFEOM) which have
been viewed differently with regards to pathogenesis following identification of inheritance patterns and study of the specific
defect. We present a short review of the role of genetic testing and the inheritance patterns in strabismus.

Hippocrates1 was the first to observe Genetic Mechanisms: A Summary affects both sexes and there is male to
the higher prevalence of strabismus Every individual has 46 chromosomes, male transmission.
in patients with family history of the in 23 pairs. 22 pairs of genes are the
same. Twin studies and family studies autosomes, involved in formation of the Strabismus in mitochondrial
have identified significant genetic basis body. There are two sex chromosomes, disorders
for strabismus, particularly in families2. XX in the females and XY in the males. A Mitochondrial cytopathies encompass
The diagnosis and care of patients with mutation involving the X chromosome a group of disorders characterised
eye diseases has been revolutionized will manifest in males, since they have by mitochondrial dysfunction with
by the introduction of multi-gene tests only one X chromosome. Females have biochemical or histopathological
revolutionised by the introduction two X-chromosomes and mutation in evidence of the same. These are multi-
of cutting-edge gene sequencing one of the X-chromosomes will result in system disorders with usual onset in
technologies. Genetic tests can be a carrier state. The autosomal disorders childhood with progressive, typically
utilised for carrier screening, which may have a dominant or recessive symmetric external ophthalmoplegia
improves the choice of reproductive pattern of inheritance. The autosomal among systemic features (Table
options for those diagnosed as carriers. recessive (AR) disorders affect siblings 1). Chronic progressive external
Molecular diagnosis also forms the in one generation while the parents ophthalmoplegia (CPEO) includes
basis for evaluating family members are normal and manifest only if both a group of disorders like Kearns
and identifying those at risk early, with copies of the gene are defective. The Sayre syndrome3, mitochondrial
consequent intervention to prevent disorder affects both sexes and there is encephalopathy with lactic acidosis
or reduce morbidity and mortality. 50% chance of carrier state and a 25% and stroke (MELAS) and myoclonus,
The genetic inheritance patterns in chance of the manifest phenotype if epilepsy with ragged red fibres
strabismus are complex and do not both parents are carriers of the mutant (MERRF), the last of which is typically
conform to a simple Mendelian plan trait. Consanguinity is associated not associated with ophthalmoplegia.
and involve the complex interaction with higher prevalence of recessive CPEO inheritance may be sporadic,
of hereditary and environmental disorders. Autosomal dominant (AD) show Mendelian pattern or maternal
factors. A thorough evaluation includes disorders, on the contrary, manifest inheritance. Kearns-Sayre syndrome
good family history, assessment of even if a single copy of the gene is represents the most severe phenotype
environmental factors that influence carrying the mutation and the risk of associated with multiple mitochondrial
the disorders and appropriate molecular a child inheriting the disease is 50% DNA deletions4,5 which are very variable
diagnosis with early intervention and if one parent has the disease, which and point mutation identified recently,
genetic counselling. the adenine-to-guanine transition at

14 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Table 1: Loci and genes in mitochondrial cytopathies Duane’s retraction syndrome
(DRS)
Disorder Inheritance Gene Locus
DRS is the commonest of CCDDs13-15,
CPEO1 AD C10orf2 10q 24 contributing about 1-5% of all
strabismus cases. It is marked by the
CPEO2/3 AD ANT1 4q35 absence or hypoplasia of the abducens
nucleus with aberrant innervation
KSS Mt Multiple Mt DNA deletions Mt DNA of the lateral rectus by branches of
the oculomotor nerve, resulting in
CPEO with AD Not identified ___ impaired horizontal eye movements
hypogonadism with narrowing of the palpebral fissure
and globe retraction on attempted
CPEO with severe AR Not identified ___ adduction, along with cosmetically
cardiomyopathy significant upshoot/downshoot of the
globe. Majority of the cases of DRS are
AD, autosomal dominant; AR, autosomal recessive; CPEO, chronic progressive external sporadic (85-90%), hereditary cases
ophthalmoplegia; KSS, Kearns-Sayre syndrome; mt, mitochondrial. being about 10%. Till date, four genes
for DRS have been identified, three of
Table 2: Summary of loci and genes in CCDDs which, MAFB16, HOXA117, and SALL418,19,
are transcription factors associated with
Disorder Inheritance Gene Locus syndromic DRS. The fourth, CHN120,
2q31 is associated with isolated ocular
DRS AD Not identified disease and is the only locus for non-
syndromic DRS. Phenotype mapping
DRS Chromosomal ? CPAH 8q13 of familial cases inherited as a bilateral
anomalies autosomal dominant trait has identified
DRS (Okihiro syndrome) AD SALL4 20q13 the DURS2 locus on chromosome 2q31
MBS1 Chromosomal 13q12-13 Not identified and heterozygous mutations in CHN1.
anomalies Phenotypic variability is noted even
MBS2 AD 3q21-22 Not identified among individuals with heterozygous
MBS3 AD CHN1 mutations. Mutation in SALL4
10q 21.3-q22.1 Not identified gene located on 20q 13.2 is associated
with a large spectrum of overlapping
CFEOM1 AD KIF21A 12p11-q12 disorders combining DRS with radial
limb abnormalities, facial asymmetry,
CFEOM2 AR PHOX2A 11q13.4 hearing deficits, anal stenosis, and
cardiac and renal abnormalities.
CFEOM3 AD TUBB3 16q 24.3 SALL4 mutations have also been
reported in individuals with radial
AD, autosomal dominant; DRS, Duane’s retraction syndrome; MBS, Mobius syndrome; CFEOM, ray syndrome without DRS. Duane
Congenital fibrosis of extraocular muscles. radial ray (Okihiro) syndrome, Holt-
Oram syndrome, and acro-renal-ocular
position 3243 of mitochondrial DNA operative Bell’s phenomenon. syndrome are associated with SALL4
(A3243G)6-8, with a classic triad of mutations. Wildervanck syndrome is
CPEO, pigmentary retinopathy and Genetics of incomitant strabismus associated with DRS and Klippel-Feil
conduction defects. It is of note that Congenital Cranial dysinnervation anomaly with hearing loss and genetic
the greater the mt DNA deletion, more disorders (CCDDs) are a group of studies revealed a microdeletion on
severe is the phenotypic expression. disorders9-12 (Table 2) resulting from X chromosome involving a single
MELAS is often maternally inherited, abnormal development of cranial gene. Goldenhar syndrome (oculo-
with CPEO, pigmentary retinopathy, nerve nuclei and their motor axons, auro-vertebral dysplasia) which is
stroke like episodes and retrochiasmal with innervational defect causing seen in about 3% of DRS patients
vision loss. Skeletal muscle biopsy secondary fibrotic changes in the has been associated with deletions in
in these conditions reveals the target muscles. The genetic analysis in chromosome 22q11.2. However, the
characteristic ‘ragged red fibres”. Care is these disorders has led to a paradigm genes linking it with DRS remains to be
to be taken while managing progressive shift in the understanding of these
ophthalmoplegia due to the severe diseases, wherein the muscle itself was
loss of muscle function and poor post- previously considered the primary
target.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 15

Subspeciality-Pediatric Ophthalmology

isolated. MAFB mutations cause Duane Type 1, Type 2 and Type 326. CFEOM involves an interaction between
syndrome with or without hearing 1 is an autosomal dominant disorder environmental and genetic factors.
loss. DRS in association with cervical characterised by bilateral ptosis, Studies36 have identified family history,
spine and radial ray abnormalities and restrictedupgazewithhypotropialinked low birth weight, hypermetropia, ROP
hearing loss with AD inheritance is to heterozygous missense mutations and maternal smoking as risk factors.
known as Okihiro syndrome or Duane in KIF21A27 located on 12q 1228, a Family studies reveal a strong genetic
radial ray syndrome. This disorder has kinesin motor protein involved in the component of comitant strabismus with
been mapped to chromosome 20q13, neuronal development by controlling about 30% probands with strabismus
with truncating mutations identified the growth of microtubules by an auto- reporting a family member or close
in SALL4. The connection between inhibition mechanism and loss of this relative with the same. Twin studies
infantile esotropia and DRS has been function adversely interacts with cell have revealed higher concordance
studied recently, of note the Strabismus growth. CFEOM 2 has an autosomal rates in monozygotic twins, implying a
Inheritance Study in Tasmania (SIST)21, recessive inheritance with bilateral strong genetic component. The genetic
which recruited 133 families with ptosis, exotropia and severe restrictive linkage appears to be different among
infantile esotropia with 2 families strabismus with pupillary involvement types of comitant strabismus, being
having multiple DRS cases. Previous associated with homozygous mutations more in esotropia and hyperopic error.
linkage studies showed DRS and 8q 12- in PHOX2A gene on 11q 13.429,30. This Parikh et al37 have assessed linkage
13 linkage. SIST study demonstrated the factor is critical for the development analysis in a family with presumed
association between DRS and infantile of oculomotor and trochlear nerves. recessive inheritance and the first locus
esotropia with trisomy 8. Homozygous, CFEOM 3 is autosomal dominant and has been isolated as STBMS1 on 7p 22.1.
recessive mutations in HOXA1 on 7p presents with variable degree of ptosis Other possible loci are on chromosome
15.2 are associated with horizontal gaze and hypotropia ranging from mild 7 and 4, although not yet isolated.
palsy, hearing loss, facial weakness and to absent. CFEOM3 can result from The pattern in comitant strabismus
can cause overlap in phenotype with heterozygous missense mutations in is more complex, not conforming to
DRS type 3 and Mobius syndrome. TUBB331 on 16q 24.3 which encodes for a- a Mendelian system with different
tubulin protein involved in the growth expression among pedigrees.
Mobius Syndrome and regeneration of microtubules,
Mobius syndrome22-24 is a rare CCDD particularly in response to cell injury. Summary and conclusion
characterised by non-progressive Recently, a rare homozygous missense Genetic testing and analysis of families
bilateral facial palsy with abduction mutation in TUBB2B32 was linked to for inheritable traits continues to expand
deficit due 6th nerve paresis or CFEOM and polymicrogyria. CFEOM our present knowledge of strabismus
hypoplasia and other cranial nerve 3 is more commonly associated with and genetics. A thorough family history
involvement, particularly 12th other neurological defects33 with the with early clinical evaluation and
nerve, along with limb defects. Both more severe phenotypes manifesting genetic testing in selected cases can help
environmental (intrauterine exposure with impaired intellect, absent anterior with early diagnosis of these disorders.
to cocaine, misoprostol or thalidomide) commissure and corpus callosum and The combination of clinical findings
and genetic factors are implicated in autistic disorders among others. and gene product characterization
pathogenesis. The vast majority are has led to a better understanding of
sporadic, implying environmental Horizontal gaze palsy with these disorders, particularly CCDDs.
factors or de novo mutations. Limited progressive scoliosis (HGPPS) The high prevalence of sporadic cases
number of familial cases are reported HGPPS34 is a rare autosomal recessive without familial basis, emphasises the
with a founder mutation (mutation disorder characterized by progressive role of environmental factors, including
limited to specific families or ethnic scoliosis and abduction deficit. In teratogenic factors during intrauterine
groups) in HOXB125 located on 17q 2004, mutations in ROBO335 gene in development. It is important to screen
21.32 associated with a recessive MBS consanguineous families was identified babies with high risk factors like
like syndrome, albeit with preserved as the culprit. Compound heterozygous low birth weight, family history of
abduction. mutations in non-consanguineous strabismus, ROP, maternal history of
families has been linked with smoking among others for strabismus
Congenital Fibrosis of the plagiocephaly and torticollis with and its sequelae like amblyopia.
Extraocular Muscles (CFEOM) progressive scoliosis.
CFEOM is hereditary, non-progressive References
disease characterised by restrictive Genetics of comitant strabismus 1. Lorenz B. Genetics of isolated and
ophthalmoplegia, ptosis and strabismus Comitant strabismus is a common
with dysfunction of the third and fourth problem affecting 3-5% of paediatric syndromic strabismus: facts and
nerves. Three phenotypes are described- population and the pathogenesis perspectives. Strabismus 2002: 10: 147–
156.

16 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

2. Podgor MJ, Remaley NA, Chew Chen, J., Gong, Y., Zhu, H., Yu, R. and 2004: 25: 189–198.
E. Associations between siblings Liu, H. (2016) Prevalence of amblyopia
for esotropia and exotropia. Arch and strabismus in Eastern China: results 22. Mob¨ ius, P. J. Ueber angeborene
Ophthalmol 1996: 114: 739–744. from screening of preschool children doppelseitige Abducens-Facialis-
aged 36-72 months. Br. J. Ophthalmol.,
3. Kearns TP, Sayre GP. Retinitis 100, 515–519. La¨hmung. Mu¨nchener Medicinische
pigmentosa, external ophthalmoplegia Wochenschrift. About Congenital 35,
and complete heart block. Unusual 14. Murillo-Correa, C.E., Kon-Jara, V., Engle, 91–94 (1888).
syndrome with histologic study in one E.C. and Zenteno, J.C. (2009) Clinical
of two cases. Arch Ophthalmol 1958; features associated with an I126M 23. Verzijl, H. T., van der Zwaag, B.,
60:280–9. alpha2chimaerin mutation in a family Lammens, M., ten Donkelaar, H. J. &
with autosomal-dominant Duane Padberg, G. W. The neuropathology of
4. Holt IJ, Harding AE, Morgan-Hughes retraction syndrome. J. Aapos., 13, 245– hereditary congenital facial palsy vs
JA. Deletions of mitochondrial DNA 248. Mobius syndrome. Neurology 64, 649–
in patients with mitochondrial 653 (2005).
myopathies. Nature 1988; 331:717–9. 15. Gurwood, A.S. and Terrigno, C.A. (2000)
Duane’s retraction syndrome: literature 24. Assaf, A. A. Congenital innervation
5. Moraes CT, DiMauro S, Zeviani M, review. Optometry, 71, 722–726. dysgenesis syndrome (CID)/congenital
Lombes A, Shanske S, Miranda AF, cranial dysinnervation disorders
Nakase H, Bonilla E, Werneck LC, 16. Park, J.G., Tischfield, M.A., Nugent, A.A., (CCDDs). Eye (Lond) 25, 1251–1261
Servidei S. Mitochondrial DNA deletions Cheng, L., Di Gioia, S.A., Chan, W.M., (2011).
in progressive external ophthalmoplegia Maconachie, G., Bosley, T.M., Summers,
and Kearns-Sayre syndrome. N Engl J C.G., Hunter, D.G. et al. (2016) Loss of 25. Webb, B. D. et al. HOXB1 founder
Med 1989; 320:1293–9. MAFB function in humans and mice mutation in humans recapitulates the
causes Duane syndrome, aberrant phenotype of Hoxb1-/- mice. Am. J.
6. Hansrote S, Croul S, Selak M, extraocular muscle innervation, and Hum. Genet. 91, 171–179 (2012).
Kalman B, Schwartzman RJ. External inner-ear defects. Am. J. Hum. Genet., 98,
ophthalmoplegia with severe 1220–1227. 26. Gutowski NJ, Bosley TM, Engle EC.
progressive multiorgan involvement 110th ENMC International Workshop:
associated with the mtDNA A3243G 17. Tischfield, M.A., Bosley, T.M., Salih, M.A., the congenital cranial dysinnervation
mutation. J Neurol Sci 2002; 197:63–7. Alorainy, I.A., Sener, E.C., Nester, M.J., disorders (CCDDs). Neuromuscul Disord
Oystreck, D.T., Chan, W.M., Andrews, C., 2003; 13:573–8.
7. Bosbach S, Kornblum C, Schroder R, Erickson, R.P. et al. (2005) Homozygous
Wagner M. Executive and visuospatial HOXA1 mutations disrupt human 27. Yamada K, Andrews C, Chan WM,
deficits in patients with chronic brainstem, inner ear, cardiovascular and McKeown CA, Magli A, de Berardinis
progressive external ophthalmoplegia cognitive development. Nat. Genet., 37, T, Loewenstein A, Lazar M, O’Keefe
and Kearns-Sayre syndrome. Brain 2003; 1035–1037. M, Letson R, London A, Ruttum M,
126:1231–40. Matsumoto N, Saito N, Morris L, Del
18. Al-Baradie, R., Yamada, K., St Hilaire, C., Monte M, Johnson RH, Uyama E,
8. Servidei S. Mitochondrial Chan, W.M., Andrews, C., McIntosh, N., Houtman WA, de Vries B, Carlow TJ,
encephalomyopathies: gene mutation. Nakano, M., Martonyi, E.J., Raymond, Hart BL, Krawiecki N, Shoffner J, Vogel
Neuromuscul Disord 2004; 14:107–16. W.R., Okumura, S. et al. (2002) Duane MC, Katowitz J, Goldstein SM, Levin
radial ray syndrome (Okihiro syndrome) AV, Sener EC, Ozturk BT, Akarsu AN,
9. Gutowski, N.J., Bosley, T.M. and Engle, maps to 20q13 and results from Brodsky MC, Hanisch F, Cruse RP,
E.C. (2003) 110th ENMC International mutations in SALL4, a new member of Zubcov AA, Robb RM, Roggenkaemper
Workshop: the congenital cranial the SAL family. Am. J. Hum. Genet., 71, P, Gottlob I, Kowal L, Battu R, Traboulsi
dysinnervation disorders (CCDDs). 1195–1199. EI, Franceschini P, Newlin A, Demer
Naarden, The Netherlands, 25– 27 JL, Engle EC. Heterozygous mutations
October 2002. Neuromuscul. Disord., 13, 19. Kohlhase, J., Heinrich, M., Schubert, of the kinesin KIF21A in congenital
573–578. L., Liebers, M., Kispert, A., Laccone, fibrosis of the extraocular muscles type
F., Turnpenny, P., Winter, R.M. and 1 (CFEOM1). Nat Genet 2003; 35:318–21.
10. Engle, E.C. (2002) The molecular basis Reardon, W. (2002) Okihiro syndrome is
of the congenital fibrosis syndromes. caused by SALL4 mutations. Hum. Mol. 28. Engle EC, Kunkel LM, Specht LA, Beggs
Strabismus, 10, 125–128. Genet., 11, 2979–2987. AH. Mapping a gene for congenital
fibrosis of the extraocular muscles to the
11. Graeber, C.P., Hunter, D.G. and Engle, E.C. 20. Miyake, N., Chilton, J., Psatha, M., centromeric region of chromosome 12.
(2013) The genetic basis of incomitant Cheng, L., Andrews, C., Chan, W.M., Nat Genet 1994; 7:69–73.
strabismus: consolidation of the current Law, K., Crosier, M., Lindsay, S., Cheung,
knowledge of the genetic foundations of M. et al. (2008) Human CHN1 mutations 29. Wang SM, Zwaan J, Mullaney PB, Jabak
disease. Semin. Ophthalmol., 28, 427– hyperactivate alpha2chimaerin and MH, Al-Awad A, Beggs AH, Engle EC.
437. cause Duane’s retraction syndrome. Congenital fibrosis of the extraocular
Science, 321, 839–843. muscles type 2, an inherited exotropic
12. Heidary, G., Engle, E.C. and Hunter, strabismus fixus, maps to distal 11q13.
D.G. (2008) Congenital fibrosis of 21. Connell BJ, Wilkinson RM, Barbour JM Am J Hum Genet 1998; 63:517–25.
the extraocular muscles. Semin. et al. Are Duane syndrome and infantile
Ophthalmol., 23, 3–8. esotropia allelic? Ophthalmic Genet 30. Nakano M, Yamada K, Fain J, Sener EC,
Selleck CJ, Awad AH, Zwaan J, Mullaney
13. Chen, X., Fu, Z., Yu, J., Ding, H., Bai, J.,

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 17

Subspeciality-Pediatric Ophthalmology

PB, Bosley TM, Engle EC. Homozygous congenital cranial dysinnervation comitant strabismus: a systematic
mutations in ARIX (PHOX2A) result in disorders (CCDDs): insights into axon review of the literature. JAMA
congenital fibrosis of the extraocular growth and guidance. Hum Mol Genet. Ophthalmol 2013: 131: 1179–1186.
muscles type 2. Nat Genet 2001; 29:315– 2017;26(R1): R37-R44. doi:10.1093/hmg/ 37. Parikh V, Shugart YY, Doheny KF et al.
20. ddx168 A strabismus susceptibility locus on
chromosome 7p. Proc Natl Acad Sci USA
31. Whitman, M.C., Andrews, C., Chan, 34. Sharpe JA, Silversides JL, Blair RD. 2003: 100: 12283–12288.
W.M., Tischfield, M.A., Stasheff, S.F., Familial paralysis of horizontal gaze.
Brancati, F., Ortiz-Gonzalez, X., Nuovo, Associated with pendular nystagmus, Corresponding Author:
S., Garaci, F., MacKinnon, S.E. et al. progressive scoliosis, and facial
(2016) Two unique TUBB3 mutations contraction with myokymia. Neurology. Prof. Pradeep Sharma MD
cause both CFEOM3 and malformations Nov; 1975 25(11):1035–1040. [PubMed: Pediatric ophthalmology, Strabismus,
of cortical development. Am. J. Med. 1237821]. Neuroophthalmology and Oculoplasty
Genet. A, 170, 297–305. Dr. Rajendra Prasad Centre for Ophthalmic
35. Chan WM, Traboulsi EI, Arthur B, Sciences. AIIMS, New Delhi, India.
32. Cederquist GY, Luchniak A, Tischfield Friedman N, Andrews C, Engle EC.
MA, et al. An inherited TUBB2B Horizontal gaze palsy with progressive
mutation alters a kinesin-binding site scoliosis can result from compound
and causes polymicrogyria, CFEOM and heterozygous mutations in ROBO3.
axon dysinnervation. Human molecular Journal of medical genetics. Mar.2006
genetics. Dec 15; 2012 21(26):5484–5499. 43(3):e11. [PubMed: 16525029].
[PubMed: 23001566].
36. Maconachie GDE, Gottlob I, McLean RJ.
33. Whitman MC, Engle EC. Ocular Risk factors and genetics in common

18 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Advances in Strabismus

Deepsekhar Das MD, Swati Phuljhele MD, Rohit Saxena MD, PhD
Strabismus and Pediatric Ophthalmology Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India.

Abstract: The knowledge and understanding of strabismus have undergone drastic changes in the last 3 decades. The advent of newer
imaging modalities, their application has augmented the previous existing information on various types of squint and with the discovery of
new surgical procedures, surgical management has become more customized. Herein, the authors discuss what is new in strabismus.

As we progress into the 21st century, 7th cranial nerve in cases of Mobius of dichoptic iPad games had significant
there have been some fascinating Syndrome8. visual gain 3 months post treatment. In
developments in the knowledge, Imaging techniques like ASOCT and a study at our centre where dichoptic
understanding and the management of UBM have allowed the visualization tetris game was compared to patching
strabismus. of muscle insertions in vivo and in in cases of anisometropic amblyopia,
I. Investigations in Strabismus non-invasive ways. It aids in surgical both were found to yield similar results
The understanding of the pathogenesis planning, in cases of residual and with the dichoptic group having a
of strabismus has improved with the consecutive strabismus, to know the better contrast sensitivity and near
improvement in imaging techniques. location of muscle. Presence of slipped stereoacuity. Medical treatment in form
Extraocular muscle pulleys, which are muscle or stretched scar warrants of levodopa and citi-choline has also
condensation of posterior tenon’s fascia exploration of the same eye while cases been tried in amblyopia with short-lived
have been described on high resolution where muscle is found to be in its place but favourable outcome15,16. The recent
MRI. Their role in pathogenesis of A-V can be treated as denovo9,10. years have also noted a marked boom in
pattern, incomitant strabismus have II. Amblyopia Management the use of virtual reality (VR) in all fields
now been understood which has help in Multiple new developments have of medicine, and ophthalmology is no
improvement of surgical management occurred in the field of managing exception. VR headsets have been used
of these cases1. Similarly ‘Sagging eye amblyopia, from moving on from full to project different stimuli to the 2 eyes,
syndrome’ and ‘heavy eye syndrome’ time occlusion to part time occlusion integrating dichoptics and perceptual
has been explained by the inferior to no occlusion. Functional MRI and learning. This has shown promising
displacement of the lateral rectus diffusion tensor imaging have been outcomes in improving neuroplasticity
pulley2,3. The Yokohama procedure used for the evaluation of brain cluster in children with amblyopia17.
for highly myopic strabismus was activation in strabismic amblyopes11.
devised on the basis on MRI findings4. and it has shown that the improvement III. Strabismus Management
Another study has explained in the in visual acuity post-occlusion therapy
recent times how the shifting of muscle correlates with the hemodynamic Medical Management
pulley can mimic a superior oblique activity. The use of video games along The role of Botulinum Type A toxin has
palsy5. Dynamic MRI allows evaluation with occlusion therapy has been proved been well documented for the infantile
of muscle contractility which can be to be beneficial in cases of anisometropic esotropia, partially accommodative
useful in assessment and management amblyopia12. Dichoptic therapy refers esotropia and serves as a temporary
of paralytic strabismus, muscle loss and to simultaneously stimulating both alternative in paralytic strabismus18,19.
aberrant innervations6. It has helped eyes with each receiving a different Recently Scott described the role of
diagnosing a novel clinical entity of stimulus. This has been shown to bupivacaine in combination with
synergistic innervational downshoot7. actuate a higher level of plasticity than botulinum toxin in paralytic
Various studies have used high the use of occlusion alone13. Birch et al.14 strabismus20. The anaesthetic agent,
resolution magnetic resonance imaging compared the dichoptic iPad gameplay Bupivacaine, is an amide that has
to reveal absence/hypoplasia of sixth with sham iPad gameplay in amblyopia been proved to correct strabismus by
nerve in Duane’s retraction syndrome treatment and found that the group increasing the strength of the muscle.
and congenital 6th nerve palsy, and given amblyopia treatment in the form According to a recently published
absence/hypoplasia of both 6th and study21 reporting the efficacy of
injection treatment in horizontal

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 19

Subspeciality-Pediatric Ophthalmology

Table 1: Surgical techniques described in relevant studies with their range of corrections44

Range of mean Weighted average of Weighted average of
correction of esodeviation corrections abduction improvement in
studies (p.d.) in studies (p.d.) studies (p.d.)

Full‑tendon double VRT without 20‑36 34.71 0.39
augmentation

Full‑tendon double VRT with post 25.8‑43 38.05 1.62
augmentation

Full‑tendon double VRT with Botox 30‑66 41.74 0.58

Full‑tendon double VRT with post 40.3
augmentation + MRc (single paper)

Partial tendon double VRT without 25.1‑44.7 31.99 2.72
augmentation

Partial tendon double VRT with post 37‑62.7 58.25 0.29
augmentation

Partial tendon double VRT + MRc 37‑52 46.92 1.35

Partial tendon double VRT with post 51.08
augmentation + MRc (single paper)

Partial tendon double VRT with post Variable corrections
augmentation + LR resection + MRc/ reported (residual
chemodenervation (single paper) esotropia to consecutive
exotropia)

Single VRT + MRc 34.8‑45.4 44.05 0.84

Single VRT + post augmentation 19.6‑38.7 27.03 1.82

Single VRT + post augmentation + MRc 36.7‑45.6 42.8 1.87

p.d.=Prism diopters, VRT=Vertical rectus transposition, MRc=Medial rectus recession, Post augmentation=Posterior augmentation Foster’s suture.
*Single data

comitant strabismus in adult patients in 1993 had described a procedure to so it may not be so useful in resurgeries
with bupivacaine and botulinum A access the rectus muscle using two or in cases with pre-existing scars.
toxin, the injection treatments result in small openings. Various modifications 2. Plication
a stable clinically significant correction of his basic technique have now been The conventional surgery of
and can be a low cost alternative to the used for various types of strabismus strengthening a muscle has
conventional surgery. surgeries which include rectus muscle been resection, however, many
recessions and plications, rectus strabismologists have tried procedures
Surgical Management muscle transpositions, inferior oblique like muscle to muscle tucking and
1. Minimally Invasive Strabismus recessions, and rectus muscle posterior muscle to sclera plication procedures23.
Surgery fixations22. The basic principles of Muscle to muscle tucking procedure
In order to reduce the amount tissue performing a minimally invasive never gained much popularity as those
trauma and decrease the patient strabismus surgery are: use of corneal who advocated this experienced cheese
discomfort, minimally invasive and posterior fixation sutures, limited wiring of the muscle and the dampening
strabismus surgery is gaining popularity number of conjunctival incisions, of the overall effect with time. However,
amongstrabismologists.Bothlimbaland placed in paralimbal area over muscle recently there has been a resurgence of
fornix based incisions have been used insertion , performance of surgical steps muscle to sclera plication procedure.
since ages by the strabismus surgeons, through tunnel of conjunctival incision, The ‘muscle over the muscle’ has been
without any significant complications. and minimal dissection of perimuscular found to preserve the circulation to
However, tissue disruption in these tissue to avoid disruption. The surgical anterior chamber better24. On studying
cases, especially if not done carefully technique has a longer learning curve the effects of plication in comparison
can cause postoperative scarring and the risk of a conjunctival tear in to resection, the effects were similar for
leading to cosmetic blemish. Gobin patients having inelastic conjunctiva,

20 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

medial rectus but was not as effective Figure 1: Summary of Vertical Recti Transposition.
for lateral rectus25. The procedure is
currently practised by majority of Enhanced adjustable nasal transposition muscle origin, superior and inferior to
strabismologists and is believed to be of the split lateral rectus can be done lateral rectus for superior rectus and
reversible, atleast in early stages and to get more accurate results33. Taylor inferior rectus respectively. In 2005 he
can also be performed via minimally described the full transposition of the further modified the procedure where
invasive route. lateral rectus to medial rectus, in a case he did not perform any tenotomy or
3. Transposition Surgeries of third nerve palsy with hypotropia, split the muscle fibres. Using Prolene
Over the years transposition surgeries where the entire lateral rectus muscle and Ethibond sutures the lateral fibres
are like Hummelscheim, and Knapp’s belly was anchored to the globe just were anchored to the scleral wall at a
procedure have provided good results below the insertion of the medial rectus distance, 10 to 12 mm behind the supero-
in cases of paralytic strabismus. The muscle to correct co-existing vertical temporal and infero-temporal limbus.
latest entry in the array are Lateral deviation simultaneously. Saxena et This is termed as modified Nishida. This
Rectus to Medial Rectus transposition, al modified this by describing use of procedure preserves the anterior ciliary
Nishida’s and modified Nishida’s augmented sutures where 5–0 Ethibond arteries there by minimizing the risk of
transposing procedure and Superior were placed 8 mm behind the new anterior segment ischemia.
Rectus transposition26,27. insertion and were tied to the sclera
Vertical rectus Transposition (VRT) adjacent to the medial rectus34. Medial Johnston first advocated Superior
is used for the management of sixth transposition of split lateral rectus has rectus transposition in place of VRT
nerve palsy as well as DRS. VRT surgery also been tried with success in cases of to minimize the chance of anterior
with posterior fixation sutures has synergistic divergence35,36. segment ischemia. Later the surgery
been shown to be effective in the was compared with recession of MR
management of complete sixth nerve In 2003 Nishida et al described a where it resulted in significantly
palsy and patients of esotropic DRS28. transposition technique without improving abduction along with long-
Partial VRT has been shown to improve disinsertion of vertical muscles in a case term alignment37.
abduction and binocular single visual of sixth nerve palsy. They dissected the
field in cases of exotropic Duane intermuscular septum and fascia along 4. Periosteal Fixation Procedures
syndrome29. This surgery can be made the lateral wall of each vertical recti
adjustable by crossing over of vertical following which the muscle bellies Periosteal fixation procedures can serve
recti muscles over the lateral rectus were split longitudinally around 15mm as an important remedy in cases where
and putting them on adjustable suture. posterior to the insertion and using 6-0 transposition surgeries fail to give the
The various options for transposition nylon sutures the lateral fibres were desired outcome or where muscles
are described in (Figure 1). 14 Sen et al sutures 8mm posterior to lateral rectus cannot be transposed because of risk
did a systematic review of publications for anterior segment ischemia. The
of vertical rectus procedures for
management of lateral rectus palsy
and evaluated their outcomes and the
complications to determine the effect
of vertical rectus transposition (VRT)
surgery in patients with lateral rectus
palsy (Table 1).
Y-split and medial transposition
of Lateral rectus muscle was first
described by Kaufmann in 1991, and
later described by Gokyigit30,31. In the
recent years Saxena et al has modified
this procedure where the split halves of
the lateral rectus are sutured just above
and below the insertion of the medial
rectus, along with equatorial fixation
sutures, which augment the action of
the transposed muscle32.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 21

Subspeciality-Pediatric Ophthalmology

procedure involve either fixing the nasal transposition of inferior oblique, 8. Gupta C, Sharma P, Saxena R, Garg
antagonist muscle to the periosteum or where in, inferior oblique is transposed A, Sharma S. Clinical correlation of
by tethering the globe to the periosteum 2mm nasal and posterior to the inferior imaging findings in congenital cranial
on the side of missing or paralyzed rectus. This causes more weakening dysinnervation disorders involving
muscle. Pre-caruncular periosteal of inferior oblique and is shown to be abducens nerve. Indian J Ophthalmol.
approach for medial wall periosteal more effective to correct extorsion in 2017 Feb;65(2):155-159.
anchoring of the globe has been found cases of superior oblique palsy42,43.
to be a viable option in the management 9. Takkar B, Sharma P, Singh AK, Sahay
of complete external oculomotor nerve Conclusion P. Anterior segment optical coherence
palsy38. Similarly periosteal fixation As time progresses, we learn more and tomography for identifying muscle
of the lateral rectus has been found to unravel the unexplored avenues. The status in strabismus surgery. Int J
be effective to correct retraction and management options of Strabismus Ophthalmol. 2016 Jun 18;9(6):933-4.
exodeviation in cases of exotropic DRS. have evolved, and surgical success rates
5. Yokohama Procedure have improved with newer procedures 10. Dai S, Kraft SP, Smith DR, Buncic
Yokohama in 2000 had described the available in the surgeon’s arsenal. The JR. Ultrasound biomicroscopy in
surgical procedure for “sagging eye quest for achieving alignment and strabismus reoperations. J AAPOS. 2006
syndrome” in myopia where the muscle stereopsis moves on. Jun;10(3):202-5.
bellies of the superior rectus and lateral
rectus were tied together. The surgery References 11. Gupta S, Kumaran SS, Saxena R, Gudwani
in the recent years have been tried 1. Demer JL. Evidence supporting S, Menon V, Sharma P. BOLD fMRI and
in cases of eso-hypotropic acquired DTI in strabismic amblyopes following
strabismus in non-myopic individuals extraocular muscle pulleys: refuting the occlusion therapy. Int Ophthalmol. 2016
and has yielded promising outcomes39. platygean view of extraocular muscle Aug;36(4):557-68.
Rutar and Demer have described two mechanics. J Pediatr Ophthalmol
surgical techniques in elderly and non- Strabismus. 2006 Sep-Oct;43(5):296-305. 12. Singh A, Sharma P, Saxena R. Evaluation
myopic patients with esotropia and 2. Yamaguchi M, Yokoyama T, Shiraki K. of the Role of Monocular Video Game
hypotropia caused by the LR-SR band Surgical procedure for correcting globe Play as an Adjuvant to Occlusion Therapy
degeneration inferior slippage of the LR dislocation in highly myopic strabismus. in the Management of Anisometropic
muscle. In one technique the LR and SR Am J Ophthalmol. 2010 Feb;149(2):341- Amblyopia. J Pediatr Ophthalmol
muscle margins were sutured together 346.e2. Strabismus. 2017 Jul 1;54(4):244-249.
10 mm posterior to their insertions, and 3. Chaudhuri Z, Demer JL. Sagging eye
superior transposition of the LR muscle syndrome: connective tissue involution 13. Li J, Thompson B, Deng D, Chan LY, Yu
insertion; ii) suturing the margins of the as a cause of horizontal and vertical M, Hess RF. Dichoptic training enables
LR and SR pulleys together using a non- strabismus in older patients. JAMA the adult amblyopic brain to learn. Curr
absorbable suture40. Ophthalmol. 2013 May;131(5):619-25. Biol. 2013 Apr 22;23(8):R308-9.
6. Combined Recession-resection 4. Yamaguchi M, Yokoyama T, Shiraki K.
procedure Surgical procedure for correcting globe 14. Birch EE, Li SL, Jost RM, Morale SE, De La
Combined resection recession surgery dislocation in highly myopic strabismus. Cruz A, Stager D Jr, Dao L, Stager DR Sr.
on the same rectus muscle have Am J Ophthalmol. 2010 Feb;149(2):341- Binocular iPad treatment for amblyopia
been found to be effective in the 346.e2. in preschool children. J AAPOS. 2015
management of cases with paralytic 5. Suh SY, Le A, Clark RA, Demer JL. Feb;19(1):6-11.
strabismus and near -distance disparity. Rectus Pulley Displacements without
Studies have demonstrated the same to Abnormal Oblique Contractility Explain 15. Bhartiya P, Sharma P, Biswas NR, Tandon
be beneficial in correcting a persistent Strabismus in Superior Oblique Palsy. R, Khokhar SK. Levodopa-carbidopa
cyclic esotropia41. Ophthalmology. 2016 Jun;123(6):1222- with occlusion in older children with
7. Inferior Oblique Anterior Nasal 31. amblyopia. J AAPOS. 2002 Dec;6(6):368-
Transposition 6. Teodorescu L, Ionescu V. Rezonanta 72.
Inferior oblique weakening is an integral magnetica nucleara dinamic în
part of management of superior oblique evaluarea pacientului cu strabism 16. Pawar PV, Mumbare SS, Patil MS,
palsy. Stager et al in 2003 described the [Dynamic nuclear magnetic resonance Ramakrishnan S. Effectiveness of the
in strabismus]. Oftalmologia. 2010; 54 addition of citicoline to patching in the
(2) : 123-8. Romanian. PMID: 20827922. treatment of amblyopia around visual
7. Sharma P, Chaurasia S, Rasal A, Angmo maturity: a randomized controlled trial.
D. Synergistic innervational downshoot: Indian J Ophthalmol. 2014 Feb;62(2):124-
a distinct vertical dysinnervation 9.
pattern and its unique management. Can
J Ophthalmol. 2017 Feb;52(1):e31-e38. 17. Coco-Martin MB, Piñero DP, Leal-Vega
L, Hernández-Rodríguez CJ, Adiego J,
Molina-Martín A, de Fez D, Arenillas
JF. The Potential of Virtual Reality for
Inducing Neuroplasticity in Children
with Amblyopia. J Ophthalmol. 2020
Jun 29;2020:7067846.

18. Issaho DC, Carvalho FRS, Tabuse MKU,
Carrijo-Carvalho LC, de Freitas D.
The Use of Botulinum Toxin to Treat

22 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Infantile Esotropia: A Systematic Review AAPOS. 2018 Feb;22(1):12-16.e1. 38. Saxena R, Sinha A, Sharma P, Phuljhele
With Meta-Analysis. Invest Ophthalmol S, Menon V. Precaruncular approach for
Vis Sci. 2017 Oct 1;58(12):5468-5476. 29. Sharma P, Tomer R, Menon V, Saxena medial orbital wall periosteal anchoring
R, Sharma A. Evaluation of periosteal of the globe in oculomotor nerve palsy. J
19. Flores-Reyes EM, Castillo-López MG, fixation of lateral rectus and partial VRT AAPOS. 2009 Dec;13(6):578-82.
Toledo-Silva R, Vargas-Ortega J, Murillo- for cases of exotropic Duane’s retraction
Correa CE, Aguilar-Ruiz A. Botulinum syndrome. Indian J Ophthalmol. 2014 39. Serafino M, Scaramuzzi M, Villani E,
toxin type A as treatment of partially Feb;62(2):204-8. Nucci P. “Yokoyama procedure” efficacy
accommodative esotropia. Arch Soc Esp on non-highly myopic patients with
Oftalmol. 2016 Mar;91(3):120-4. English, 30. Kaufmann H. “Lateralis splitting” bei acquired esotropia and hypotropia. Eur
Spanish. totaler Okulomotoriusparalyse mit J Ophthalmol. 2020 Jul;30(4):676-679.
Trochlearisparese [“Lateralis splitting”
20. Scott AB, Miller JM, Shieh KR. in total oculomotor paralysis with 40. Rutar T, Demer JL. “Heavy Eye”
Bupivacaine injection of the lateral trochlear nerve paralysis]. Fortschr syndrome in the absence of high myopia:
rectus muscle to treat esotropia. J Ophthalmol. 1991;88(3):314-316. A connective tissue degeneration in
AAPOS. 2009 Apr;13(2):119-22. elderly strabismic patients. J AAPOS.
31. Gokyigit B, Akar S, Satana B, Demirok 2009 Feb;13(1):36-44.
21. Debert I, Miller JM, Danh KK, Scott AB. A, Yilmaz OF. Medial transposition of a
Pharmacologic injection treatment of split lateral rectus muscle for complete 41. Bhaskaran K, Shashni AK, Sharma
comitant strabismus. J AAPOS. 2016 oculomotor nerve palsy. J AAPOS. 2013 P, Saxena R, Phuljhele S. Combined
Apr;20(2):106-111.e2. Aug;17(4):402-10. resection-recession in true divergence
excess sensory exotropia. J AAPOS. 2019
22. Mojon DS. Review: minimally invasive 32. Saxena R, Sharma M, Singh D, Dhiman Oct;23(5):258.e1-258.e4.
strabismus surgery. Eye (Lond). 2015 R, Sharma P. Medial transposition of
Feb;29(2):225-33. split lateral rectus augmented with 42. Gaur N, Sharma P, Verma S, Takkar B,
fixation sutures in cases of complete Dhar S. Surgical correction of persistent
23. Sharma P, Gaur N. Plication: How apt in third nerve palsy. Br J Ophthalmol. 2016 adult-onset cyclic strabismus. J AAPOS.
application? Indian J Ophthalmol. 2017 May;100(5):585-7. 2017 Feb;21(1):77-78.
Sep;65(9):785-786.
33. Saxena R, Sethi A, Dhiman R, Sharma 43. Saxena R, Sharma M, Singh D, Sharma
24. Wright KW, Lanier AB. Effect of a M, Sharma P. Enhanced adjustable P. Anterior and nasal transposition
modified rectus tuck on anterior nasal transposition of split lateral rectus of inferior oblique muscle in cases of
segment circulation in monkeys. J muscle for surgical management of superior oblique palsy. J AAPOS. 2017
Pediatr Ophthalmol Strabismus. 1991 oculomotor nerve palsy. J AAPOS. 2020 Aug;21(4):282-285.
Mar-Apr;28(2):77-81. Jun;24(3):183-186.
44. Sen S, Dhiman R, Saxena R, Phuljhele S,
25. Oltra EZ, Pineles SL, Demer JL, Quan AV, 34. Saxena R, Sharma M, Singh D, Sharma Sharma P. Vertical rectus transposition
Velez FG. The effect of rectus muscle P. Full tendon medial transposition of procedures for lateral rectus palsy: A
recession, resection and plication on lateral rectus with augmentation sutures systematic review. Indian J Ophthalmol.
anterior segment circulation in humans. in cases of complete third nerve palsy. Br 2019 Nov;67(11):1793-1799.
Br J Ophthalmol. 2015 Apr;99(4):556-60. J Ophthalmol. 2018 Jun;102(6):715-717.
Corresponding Author:
26. Nishida Y, Inatomi A, Aoki Y, Hayashi 35. Sharma P, Saxena R, Bhaskaran K,
O, Iwami T, Oda S, Nakamura J, Kani Dhiman R, Sethi A, Obedulla H. Dr. Swati Phuljhele MD
K. A muscle transposition procedure Augmented medial transposition of Strabismus and Pediatric Ophthalmology
for abducens palsy, in which the split lateral rectus in the management Services, Dr. Rajendra Prasad Centre for
halves of the vertical rectus muscle of synergistic divergence. J AAPOS. 2020 Ophthalmic Sciences. AIIMS, New Delhi, India.
bellies are sutured onto the sclera. Jpn J Feb;24(1):37-40.
Ophthalmol. 2003 May-Jun;47(3):281-6.
36. Saxena R, Phuljhele S, Sharma P, Pinto
27. Nishida Y, Hayashi O, Oda S, Kakinoki M, CN. Periosteal Fixation Procedures in the
Miyake T, Inoki Y, Iwami T, Mekada A, Management of Incomitant Strabismus.
Okada A. A simple muscle transposition Middle East Afr J Ophthalmol. 2015 Jul-
procedure for abducens palsy without Sep;22(3):320-6.
tenotomy or splitting muscles. Jpn J
Ophthalmol. 2005 Mar-Apr;49(2):179-80. 37. Lee YH, Lambert SR. Outcomes after
superior rectus transposition and medial
28. Agarwal R, Sharma M, Saxena R, Sharma rectus recession versus vertical recti
P. Surgical outcome of superior rectus transposition for sixth nerve palsy. Am
transposition in esotropic Duane J Ophthalmol. 2017;177:100–5.
syndrome and abducens nerve palsy. J

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 23

Subspeciality-Pediatric Ophthalmology

Motor and Sensory Tests in
Strabismus

Muralidhar Rajamani MD, DNB, FRCS, MRCO
Deptt. of Strabismus and Pediatric Ophthalmology, The Eye Foundation, D.B. Road, R.S. Puram, Coimbatore, Tamilnadu, India.

Strabismus evaluation does not require Figure 1: Lea Paddles. It is used to check used to prescribe glasses in children < 5
expensive or elaborate equipment. vision in children < 2 years of age and is years of age. Subjective acceptance may
What is needed is careful and meticulous based on preferential looking. be appropriate for older children
attention to details. A detailed history of age. The cycloplegic of choice in this
is first taken and the following queries age group is atropine 1% ointment. Motor evaluation of Strabismus
need to be included We use it once a day for 3 days. The The evaluation of strabismus begins
parents are instructed to apply a rice with attention to head posture.
• Relevant birth and perinatal grain of the ointment when the child Evaluation without correcting the head
history, Consanguinity among is asleep and to repeat the application posture may miss the strabismus. To
parents, Family history. if the child rubs off the ointment. bring out the head posture, it is essential
They are asked to stop application and to give the patient a age appropriate
• Onset of strabismus, intermittent/ institute cold sponging and administer fixation target especially for distance.
constant, eye preference, associated oral paracetamol if the child develops For young children, a cartoon may be
neurological complaints. fever or facial flushing. Cyclopentolate used for preverbal children. A patient
applied twice is appropriate 15 minutes with superior oblique palsy may have
• History of glasses, patching, apart is appropriate for older children. a contralateral head tilt, a patient with
strabismus surgery, sinus/ Tropicamide may also be instilled Brown’s syndrome may have a chin
maxillofacial surgery, trauma esp once as it potentiates the effect of depression, a patient with 6th nerve
facial and head injury. cyclopentolate in pigmented eyes. In palsy may have an ipsilateral face turn
children with neurological issues and (Figure 2).
• Systemic ailment/malignancy. a history of seizures, homatropine is
• History of diplopia – monocular/ more appropriate. Objective criteria are A note is made of any ptosis or
anisocoria. A ptosis may be congenital.
binocular. It may be acquired in patients with a 3rd
The evaluation of strabismus begins nerve palsy and ocular myasthenia and
with the estimation of visual acuity by may also be part of Horner’s syndrome.
age appropriate methods. Anisocoria may be seen in patients with
patients with third nerve palsy and
The following methods of visual acuity Horner’s syndrome.
testing are employed in our institute.
An estimation of the deviation may
• 4 months – 2 years of age – Lea be made with Hirschberg Test with
Paddles, Keeler Acuity (Figure 1). a penlight held at 33cm from the
patient. A nasally displaced light reflex
• 2 years – 3 years of age – Picture indicates exotropia (Figure 3) and a
Cards, Matching tests.
Figure 2: Patient with left 6th nerve palsy and a left face turn.
• 3-5 years of age – Picture cards/Lea
Symbols/Snellen and LOGMAR
charts.

• > 5 years – Snellen and LOGMAR
charts.

Refraction and glass prescription
Dry refraction without cycloplegia is
not recommended for children < 5 years

24 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology
Figure 3: Patient with left exotropia. The light reflex on the left eye is located on the nasal side
of the cornea.

Figure 4: Patient with left esotropia. The light reflex on the left eye is located on the temporal
side of the cornea.

Figure 5: Angle kappa is the angle between estimated by shining a penlight on the Figure 6: A: The eyes appear straight on the
the visual and optical axis - LXM. In clinical eyes. The center of the cornea and the Hirschberg. B: The Left eye is occluded; there
practice the angle kappa is measured on the light reflex seldom coincide. A nasally is no movement of the fellow eye. C: The
center of the cornea - LKM. displaced angle Kappa (positive angle right eye is occluded; there is no movement
temporally displaced reflex indicates Kappa) could mimic an exotropia and of the other eye. From B & C we can conclude
esotropia (Figure 4). The Hirschberg a temporally displaced angle Kappa that the eyes are orthophoric. D: Covering
is very useful in young children who (negative angle Kappa) mimics an the left eye triggers an outward movement
may not cooperate for other tests. It also esotropia – (Figure 5). of the right eye implying right esotropia. E:
helps us in getting an initial idea of the Covering the right eye triggers an inward
deviation. It should never be the only The next step is to do a cover test. The movement of the right eye implying right
test for strabismus as the position of the cover test brings out any manifest exotropia.
light reflex is variable, depends on the strabismus. It is essential to use an
pupil diameter and is also influenced accommodative target for fixation cover test with the patient’s glasses on
by angle Kappa. The angle Kappa is the and never to use torchlight. This is to and off. In esotropia the patient may
angle between the visual axis and the control accommodation and ensure have a smaller deviation with his plus
optic axis. Clinically the angle Kappa is reproducibility of measurements. Many glasses indicating an accommodative
age appropriate fixation targets are component. Vertical deviations are
available. The following are the pre- denoted by the non-fixing eye e.g if
requisites for a cover test and should not the right eye is fixing and the left eye
be forgotten. is at a higher level, we note it as left
hypertropia. It may be simpler to denote
• The patient should have central it as L/R to avoid confusions.
fixation. The Uncover test: This is done to bring
out any latent strabismus. A translucent
• The ocular motility should be occluder (e.g Spielmann’s occluder is
relatively normal in the field being used if available. The patient fixes on a
tested. accommodative target at distance/near
and the eye under cover is observed. The
• The best corrected visual acuity redressal movement of the eye when
visual acuity should be 6/18 or the occluder is observed after removing
better. the cover
Alternate cover test: This gives the total
The apparently fixing eye should be deviation – latent + manifest. The
covered and the movement of the patient fixates on a accommodative
other eye should be noted. An inward
movement would indicate exotropia
and an outward movement esotropia
– (Figure 6). It is important to do the

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 25

Subspeciality-Pediatric Ophthalmology

target and the occlude is shifted rapidly Figure 7: Representation of ocular movements. Overactions are denoted by a “+” and are
from one eye to the other. A rapid checked on version testing. Underactions are denoted by a “-“ and should be noted on duction
alternation is suggested to prevent testing.
fusional mechanisms from hiding
a latent deviation. It is important Figure 8: A loose prism set with prism Figure 9: The synoptophore or major
however to give the patient esp. the strength from to 50 prism diopters. amblyoscope. It can be used to measure both
very young and the very old sufficient objective and subjective deviations.
time to fixate on the target.
deviation. Among them measurement may be placed base down over the left
Evaluation of ocular motility: When with prism bars/loose prisms are eye. For deviations > 50 PD the prisms
asked to evaluate ocular motility in commonly used. Prisms are available are split between the two eyes e.g. a 60
postgraduate exams it is important for in strengths from 1/2 to 50 PD (prism PD deviation may be neutralized by 35
the candidate to request the examiner to diopters) (Figure 8). Plastic prisms are PD BI over one eye and 25 PD BI over
begin with a cover test. This is because generally used these days and should the fellow eye. The actual deviation is
restriction of ocular motility not in be placed in the frontal position viz. however more than the algebraic sum
line with deviation in primary position parallel to the infraorbital margin. In and needs to be read off from standard
could indicate a restrictive etiology or comitant deviations, it may not matter tables. Similarly prisms can be split
Duane’s syndrome. Let me explain – which eye the prism is placed. For between the two eyes for combined
a patient with abduction restriction paralytic and restrictive deviations, the horizontal and vertical deviations.
should have esotropia in primary prism is placed over the paretic/involved
position (assuming no intervention) eye to measure the primary deviation The synoptophore or the major
if the lateral rectus is paretic. If he is and over the normal eye to measure amblyoscope (Figure 9) can be used
orthotropic or exotropic in primary the secondary deviation. Prisms are to measure both the objective and
position – he or she is likely to have placed with their apex pointing to subjective deviations. However there
a restrictive pathology or Duane’s the deviation. By convention, they are are problems of proximal convergence
syndrome denoted by their base. For example a as the patient which may distort the
40 PD prism may be placed on the left deviations. The Maddox wing can also
A penlight is used and the patient eye with apex pointing to the left to be used to measure phorias
is asked to fixate. The penlight is neutralize an exotropia – the deviation
moved to the tertiary positions and is denoted as 40 prisms Base In or simply The Park’s three step test: The Park’s
the motility recorded. Overactions are 40 PD BI. For a left hypertropia, the prism three step test assumes weakness of
denoted by a + symbol and are noted the cyclovertical muscles as being
in version (both eyes open) testing.
This is to compare with the fellow eye.
Underactions are noted by a – symbol
and should only be noted on duction
testing. A number of grading scales are
available to grade the ocular motility.
Abduction is considered normal if the
lateral limbus just disappears under the
lateral canthus. Adduction is normal
if the line through the nasal 1/3rd of
the cornea crosses the lower punctum.
Elevation and depression may be
presumed normal if the lower or upper
limbus crosses the intercanthal line. It
is important to remember that there is
a huge variation in the palpebral fissure
and the aforementioned technique is
not sacrosanct. A suggested method to
depict over and underactions is depicted
in the (Figure 7).

Measurement of deviations: a number
of subjective and objective tests
are available to measure the ocular

26 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Figure 10a: The primary direction of action of the cyclovertical muscles is represented. responsible for vertical deviations.
Figure 10b: Patient has a R/L. The Park’s three step test presumes weakness of the cyclovertical A step by step illustration. The test
muscles. Hence in this case the muscles likely to be involved are RIR, RSO, LIO, LSR. can however give fallacious results if
Figure 10c: The R/L increases in left gaze. This narrows down the possibility to RSO and there is contracture or tethering of the
LSR – the second step. extraocular muscle. Similarly the test
may not be employed if more than one
extraocular muscle is paralyzed.

Diplopia Charting: the diplopia charting
is a quick way to identify the involved
muscle in paralytic strabismus. A
black paper is placed over the front of
a torch and a slit cut. The patient wears
a red green glass. The torch is shown
in primary position preferably in a
dark room. The patient is given 2 pens
(red and green coloured) and asked to
indicate the separation between the two
perceived lights. Crossed separation
is seen in exotropias (like in 3rd nerve
palsy) and uncrossed separation is seen
in esotropias (e.g 6th nerve palsy). The
maximum separation of the images
is seen in the direction of action of
the paralyzed muscle. For example a
patient with right 6th nerve palsy will
note maximum separation of images in
right gaze (Figure 11, Figure 12a-c).

Hess Chart: The hess chart is of
great value in diagnosis incomitant
strabismus. The patient wears red green
goggles and sits 50cm in front of a Hess
chart. There is a red light in the center
of the Hess chart and the eye with the
red glass is the fixing eye while the field
of the other eye with the green glass is
plotted. The patient uses a green torch
to indicate the position of the image
perceived by the eye wearing the red
glasses. Each small square represents 5
degrees of deviation. While interpreting
the Hess chart, the student needs to
indicate the deviation in primary
position before describing the restricted
movements and overactions (Figure 13,
14).

Assessment of the sensory status
The three grades of binocularity
need to be assessed – simultaneous
perception, fusion and stereopsis.
This may conveniently be done on the
synoptophore which has three separate
slides for the same.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 27

Subspeciality-Pediatric Ophthalmology

Figure 10d: Remember the pneumonic “superiors same side” . If the R/L worsens on right tilt patient wears red green goggles (red on
(see Video 1) the right superior oblique is the involved muscle. the right eye). Should the patient have
a left suppression, he/she shall perceive
Figure 11: Equipment for diplopia testing – only the 2 vertical red lights. If the
the torch with a slit and red green goggles. patient has a left suppression, 3 green
dots will be seen. Patients with normal
Figure 13: Equipment for Hess Charting. binocularity will see four lights with the
light at 6 o’clock seen as pink or white
depending on the ocular dominance.
Patients with a manifest strabismus and
perceiving four lights have anomalous
retinal correspondence. The worth four
dot for near is mounted on a torch and
is used to test peripheral fusion (Figure
15a & b).

The Bagolini striated glasses (Figure
16) are less dissociative than the Worth
four dot test. The striations are oriented
at 45 and 135 degrees. The patient
views a penlight through the glasses. A
central crossed response is considered
as normal.

Tests for Stereopsis: Stereopsis is the
highest grade of binocularity. The tests
rely on creating a fixation disparity. One
half of the image is seen by the right eye
and the other by the left eye. The image
is perceived in three dimensions only

Figure 14: This patient has a esotropia in primary position. Each small square represents 50.
The smaller square is for smaller movement restrictions and the outer square helps diagnose
subtle ocular motility deficits. There is a abduction restriction in the right eye with overaction
of the left medial rectus consistant with a diagnosis of right lateral rectus palsy.

Figure 12a-c: The patient wears red The Worth 4 dot test for distance is when both eyes see the picture. The two
green glasses. The maximum horizontal commonly use to test the binocular eyes may be dissociated with polaroid
separation of the images is in right gaze status and represents peripheral fusion. glasses like in the Titmus and Randot
suggesting right lateral rectus palsy. It is part of most vision charts. The tests (wirt circle – 400 to 20 seconds of

28 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Figure 15a & b: The worth four dot test for distance and near. Subspeciality-Pediatric Ophthalmology

way of avoiding monocular cues is to
use anaglyphs – printing the image in
complementary colours and using red
green goggles to dissociate the eyes
like the TNO test (480 to 15 seconds of
an arc) and the Frisby test (600 to 150
seconds of arc). It is difficult to define
a normal cut off value of stereoacuity
but anything less than 60 seconds of
arc is suspect. The aforementioned tests
measure stereoacuity for near. Frisby
Davis Distance (FD2) and the distance
Randot can be used to measure distance
stereoacuity which may be more useful
in the evaluation of intermittent
exotropia.

The four prism base out test: This is used
as a screening test for microtropia
and is based on the premise that in
microtropia the suppression scotoma
is larger than the displacement induced
by 4 prism diopters. A 4 prism placed
base out before the amblyopic eye
elicits no movement, while the same
placed before the normal eye induces a
opposite movement.

(Photo courtesy: Ms. Arya, Illustration
courtesy: Ms. Jahnavi)

References
1. Sharma P. Strabismus Simplified. CBS

publishers New Delhi 2013.
2. Rosenbaum AL, Santiago AP. Clinical

Strabismus Management. W.B.Saunders
Company 1999.
3. Von Noorden GK, Campos EC. Binocular
Vision and Ocular Motility. Mosby
2002 h t t p : / / w w w . m r c o p h t h . c o m /
examinationtechniques/strabismus.
htm (As accessed on 10th November
2020).

Corresponding Author:

Figure 16: Bagolini striated glasses. Figure 17: The Randot Stereoacuity test.

arc) – (Figure 17). The Lang test has a child may be asked to grab the wings Dr. Muralidhar Rajamani MD, DNB,
prismatic film laminated over the test. of the fly and will reach a plane higher FRCS, MRCO
This is very useful for small children than that of the test plate. Rotating Deptt. of Strabismus and Pediatric
< 3 years who may refuse to wear the the plate by 90 degrees, annuls the Ophthalmology, The Eye Foundation, D.B. Road,
polaroid/red green glasses. To check if fixation disparity and the patient no R.S. Puram, Coimbatore, Tamilnadu, India.
the child is using monocular cues, the longer identifies the picture. Another

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 29

Subspeciality-Pediatric Ophthalmology

Management of Esotropia

Soveeta Rath, Suma Ganesh
Dr. Shroff Charity Eye Hospital, Darya Ganj, New Delhi, India.

Esotropia (ET) is a form misalignment
of the eyes where one or both the eyes
are turned inwards, that can occur
at any age. It may be intermittent or
constant and may occur with near
fixation, distance fixation, or both.

It is one of the most common form Figure 1(a): Esotropia manifesting at Figure 1(b): Esotropia more for near.
of strabismus affected by risk factors distance.
like prematurity, birth asphyxia, In children <8 years of age with
neurological weakness, maternal a. Neurogenic (Abducens Palsy, esotropia atropine eye ointment twice
smoking, refractive error like high Divergence Palsy). daily for 3 days is the best cycloplegic
hyperopia1. Esotropia can be comitant agent.
or incomitant, where comitancy b. Myogenic (Myasthenia). Older children may need cyclopentolate
indicates similar deviation in all gazes. drops if high accommodation is noted.
• Restrictive In cases of children with neurological
Noorden has classified comitant issues Atropine (Homide - if atropine
esotropia as2 a. Musculofascial (Duanes). allergy develops or for older children)
remains the preferred cycloplegic agent.
Accommodative Esotropia b. Other restrictive conditions In cases of hyperopic refractive error it
(Tumor, postoperative, is strongly recommended to prescribe
Dysthyroid, Strabismus Fixus). the full atropine refraction in presence
1. Refractive Accommodative of esotropia.
esotropia (normal AC/A ratio) Amblyopia management: It is essential to
Management of the above entities will begin amblyopia treatment first after
2. Non-refractive accommodative be discussed in detail. giving the optimal refractive correction.
esotropia (high AC/A ratio) Patching of the preferred eye, duration
Dealing with any strabismus case of which depends on the degree of
3. Partially accommodative esotropia begins with a thorough history, proper amblyopia and anisometropia when
ocular examination from the basic present is started after prescribing
4. Hypo-accommodative esotropia visual acuity till the fundus evaluation. glasses.
Orthoptics work up: The preliminary
Non-Accomodative Esotropia work up begins with examination of
ocular motility to look for restriction in
1. Infantile esotropia History: Questions pertaining to timing any gaze, any oblique dysfunction, any
of onset, constant or intermittent, and abnormal head posture. Measurement
2. Basic esotropia whether it manifests only for distance of deviation for distance (in six cardinal
or near must be asked to parents. gazes) and for near has to be performed
3. Convergence excess Any history of diplopia , trauma, old using cover test. Associated findings as
photographs need to be reviewed.
4. Divergence insufficiency

5. Cyclic esotropia

6. Acute onset comitant esotropia Asessment of visual acuity: Both uniocular
and binocular vision assessment has to
Other types be done using age appropriate charts.
1. Sensory Esotropia

2. Microtropia Refraction: Both dry refraction and
cycloplegic refraction are mandatory
3. Nystagmus Blockage Syndrome in children with esotropia. Cycloplegic
agents are used carefully with regard
Incomitant esodeviations are classified to age and neurological status of these
as 2 major subtypes: children.

• Paralytic

30 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

presence of pattern, dissociated vertical Figure 2: Example illustrating a case of Refractive accommodative esotropia.
deviation and nystagmus also needs to
be documented. RE: C/S/M +6.5 DS LE: C/S/M +6.5 DS

Treatment of Accommodative esotropia: PBRT 45 PD ET PBRT 25 PD ET

Refractive accommodative esotropia: Figure 3: Example showing a case of partially accommodative esotropia.
As the name indicates here esotropia
gets corrected in all gaze by correcting Figure 4: Algorithm showing work up of partially accommodative esotropia.
the hyperopia. After a cycloplegic
refraction, full hyperopia correction controlled4. can be additionally taught divergence
is prescribed. The average refractive In cases of non-refractive esotropia with exercises.
error is +4.75 D, but ranges between + high AC/A ratio with esotropia being Hypoaccommodative esotropia with
1.5 and +7.0 D. These children have a more for near and less for distance, a normal AC/A ratio but far near point
normal accommodative convergence/ executive bifocals with top of lower of accommodation needs orthoptic
accommodation (AC/A) ratio3. segment crossing the lower pupillary exercises.
Follow up after 2 months is needed border when the child looks straight Esotropia with near distance disparity
to recheck any residual deviation and ahead. (Figure 6). The refractive error in presence of excessive convergence
amblyopia management is started in in this condition may be hyperopic, need surgical correction. Medial rectus
cases of anisometropia. These children emmetropic, or myopic5,6. Over time, the recession with Faden suture is the
usually have good binocular status. bifocal correction can be reduced slowly procedure of choice. This surgery aims
Weaning of glasses are usually started to increase divergence amplitudes and
in a decremental manner from +0.5DS,
maintaining stable visual acuity and
good alignment. Hyperopia may
increase or remain stable till roughly
7 years of age after which it starts
decreasing. This is when weaning
should be done till 14 years of age
usually and glasses will be required
lifelong for correction of residual squint.

For example: A 5 year old male child
presented with inward deviation of eyes
since last 2 years (Figure 2).

In cases, where the deviation is not fully
corrected with glasses, they are termed
as partially accommodative (Figure 3).

In such scenarios if there is greater than
10PD difference between distance and
near esotropia a detailed work up of
accommodation status has to be done as
described below (Figure 4).

Partially accommodative esotropia
needs surgery for the residual deviation.
Bilateral medial rectus recession is
the treatment of choice for the non-
accommodative part. Simultaneous
amblyopia management has to be
continued following surgery. It is
very important to educate parents
before surgery regarding continued
use of glasses following surgery to
keep the accommodative element well

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 31

Subspeciality-Pediatric Ophthalmology

Figure 5: Shows how AC/A ratio is calculated. However, in presence of preference,
• Gradient method which can be checked with a 4PD base
AC/A = Deviation with the lens-Original deviation out test, the dominant eye needs to be
Power of the lens patched 4-6 hours/day.
Normal range of AC/A ratio is between 3 and 5
Another important aspect is to rule
• Heterophoria method out any limitation of abduction in
AC/A = Deviation with at near- deviation at distance such cases to differentiate a congenital
sixth nerve palsy or Duane retraction
D syndrome.
(PD is the interpupillary distance in centimeters and D is the fixation distance
at near in diopters) Stability of angle and any change in
Figure 5: Methods of calculation of AC/A ratio. preference is checked at subsequent
monthly visits.
Figure 6: Bifocal glasses with lower segment crossing lower pupil border.
Infantile esotropia warrants early
Figure 7: Example showing a case of convergence excess esotropia manged with Faden surgery after stability of angle is
surgery. ascertained7,8. Medial rectus recession
remains the gold standard approach
to weaken medial rectus in its field of association, small refractive error (Figure 8).
action by changing the torque of the (<+2DS), cross fixation. Associations
muscle using the posterior fixation include presence of inferior oblique In children younger than 2 years,
suture (Figure 7). overaction, latent nystagmus and DVD. measurement of amount of recession to
Non-Accomodative Esotropia: Management in these cases also begins be done depends on the medial rectus
Infantile esotropia is defined as a with atropine refraction and prescribing insertion as well as deviation9.
manifest esodeviation with an onset glasses if refraction greater than +2.5
between birth and 6 months of age DS. Since most of these children have The table below gives an overview of the
characterized by large usually constant cross fixation, chances of amblyopia is amount of recession to be performed
angle deviation, with no neurological less. (Figure 9).

Non accommodative Basic Esotropia
has a gradual onset of the manifest
esodeviation after 6 months of age
without any near distance disparity.
Most of these are managed with
bilateral medial rectus recession based
on the angle of deviation.

Non-accomodative esotropia with
convergence excess and divergence
insufficiency are treated with orthoptic
exercises.

Cyclic esotropia is a rare form of non
paralytic strabismus with onset at 3 to 6
years. The cycles of squint and no squint
periods can vary between 1-4 days.
On the days of squinting large angle
esotropia of 40-50 PD can be present.
Photographic and video documentation
of timing and duration of the squinting
days is necessary in such cases and
parents are advised to document.
However only an early surgical
treatment prevents the emergence into
constant strabismus10.

Acute Comitant esotropia is a type

32 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Figure 8: Example illustrating a case of infantile esotropia. preferred to operate on the affected
amblyopic eye. Medial rectus recession
• Measured from Limbus with lateral rectus resection remains
• Small: 8.5mm to 9 mm for 20- 30 PD the standard treatment of choice.
• Medium: 9.5 mm to 10.0 mm for 30- 45 PD
• Large:10.5 mm to 11.0 mm for + 45 PD In very large angle esotropia with
Figure 9: Table showing amount of recession in infants -when measured from limbus. sensory component, transplantation of
the resected segment from lateral rectus
of acquired esotropia with similar hydrocephalus, intracranial to the medial rectus can be performed
deviation in all gazes.11 It is of 3 types – astrocytoma, and other brain and then medial rectus recession is
tumors need to be ruled out by done.
• Type I: Swan type (After Artificial neuroimaging9,11.
Interruption of Fusion) Nystagmus blockade syndrome is a
- occurs after monocular occlusion For example condition where nytsagmus has an
or loss of vision an inverse relation with esotropia.
- associated with hyperopia • 7 years old male child. Nystagmus is present when the eyes
• C/C/O sudden onset of inward are straight and it disappears when
• Type II: Burian Franceschetti type eyes are locked in esotropia. This is
(Without Preceding Disruption of deviation of eyes, blurring vision different from infantile esotropia
Fusion) for distance and near, vertigo, which have manifest latent nystagmus
- not associated with any refractive binocular diplopia since 1 month. and do not have this inverse relation.
error • RE 20/40, LE 20/40-Atropine Retroequatorial Myopexy with or
refraction+6.5 DS- Full refraction without medial rectus recession can be
• Type III: Bielchowsky type prescribed. performed10.
- associated with myopia. It occurs • CT-50PD ET for D and Near(
predominantly in young myopic without glasses) No inferior Microtropia is a very small angle
adults oblique overaction. deviations that are usually missed
- The esotropia is accompanied by • Was prescribed Fresnel prism for 2 by routine examination, which have
diplopia first only at distance and months- to avoid diplopia. amblyopia and varying levels of
eventually also at near fixation, • Operated after perceived single sensory fusion.10 It can be primary or
mild limitation of abduction in image. consecutive- that is post surgery. The 5
both eyes, and normal adduction. Sensory Esotropia is noted in conditions main characteristics of Microtropia are
which have very poor vision in one eye
• Acute esotropia of Neurological origin: due to associated ocular abnormalities 1. Amblyopia
In all cases of acute comitant like coloboma, macular scar, untreated 2. Anomalous retinal correspondence
esotropia the following conditions- cataract and corneal opacities. It is 3. Relative scotoma
Arnold - Chiari malformation, 4. Normal or near normal fusional

amplitudes
5. Defective stereoacuity
Microtropia is diagnosed by four
prism dioptre test and Bagolinis test.
The mainstay of management in such
condition is occlusion therapy for
amblyopia and glasses for refractive
correction.

Figure 10: Example showing a case of acute acquired comitant esotropia. DOS Times - Volume 26, Number 1, July-August 2020 33
BE MR recess
After 1 year ortho with glasses, no diplopia, BSV

www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

if >6 months Surgical (if >6 months) 1. Limitation of abduction or
Non surgical (if >6 months) Recess-resect (if FGT show residual LR action) for adduction.
Alternate occulusion upto 20 PD
Recess-resect+ C/L MR resect (for upto 40 PD) 2. Narrowing of palpebral aperture
Monocular Patching Vertical transposition +/- Botox 3. Retraction of the globe.
Botox chemo-denervation 4. Variable upshoot or downshoot of

globe on attempted adduction.
Goals of surgery in DRS are13

i. Improvement in abnormal head
posture

ii. Significant esotropia with
abduction limitation

iii. Cosmetic concern for severe
upshoot/downshoot or co-
contraction.

Management approaches include:13

Figure 11: Showing a case of RE type 1 DRS (pre and post surgery). - Unilateral or bilateral medial rectus
recession (based on deviation and
forced duction test).

- Superior rectus transposition +/-
MR recession.

For Example: The (Figure 11) below
shows a case of Type 1 Eso DRS with
co-contraction managed by unilateral
medial rectus recession.

Incomitant Esotropia Goals of management in the early In cases with mild co contraction and
Paralytic : Congenital or Acquired sixth stage is treatment of risk factors and in the absence of significant upshoot,
nerve palsy causes incomitant esotropia occlusion therapy to avoid diplopia. superior rectus transposition+/-MR
with the deviation is maximum in the Other nonsurgical options like prism recession can be performed to improve
side of paralysed muscle which had s therapy and Botox injection to the abduction and esotropia14.
abduction limitation. Most of these are medial rectus can be given to alleviate
usually acquired conditions presenting diplopia and prevent contracture. In Other Entities
with binocular horizontal diplopia and acquired sixth nerve palsy following
face turn. Cause of the acute acquired trauma a force duction test and force Spasm of Accomodation: Acute acquired
non comitant esotropia(AANCE) needs generation test needs to be perfomed comitant esotropia can occur in
to be evaluated. in the clinic to distinguish a paralytic children with accommodative spasm.
or restrictive mechanism. Surgical They present with variable esotropia,
The most common etiology of acquired intervention is usually done after a diplopia, pupillary miosis, ocular pain,
sixth nerve palsy is microvascular palsy minimum waiting period of six months photophobia induced pseudomyopia
in presence of uncontrolled diabetes, as there as chances of spontaneous due to excessive convergence. The
hypertension and homocysteinemia. improvement. most possible etiologies described
It can also occur following trauma The table below describes the available are psychogenic, neurogenic or
and in neurological conditions like treatment options for esotropia due to traumatic. A complete orthoptic
Foville and Millard Gublar syndrome. sixth nerve palsy:12 evaluation, atropine refraction and
In absence of any ischemic risk factors Restrictive: Duane retraction Syndrome dynamic retinoscopy is essential in all
or known history of trauma, and if remains the most common example of such cases. Mainstay of management
multiple cranial nerves are involved a restrictive mechanism of incomitant includes treatment of the cause as there
neuro-imaging is necessary. We also esotropia. Popularized by Duane the is no standard strategy15. Atropine is
need to rule out any raised intracranial major characteristics are. prescribed for a period of 3 months
pressure as sixth nerve palsy can be a to relax the excess accomodation and
false localising sign. orthoptic exercises are continued,
following which the esotropia and

34 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Figure 12: Showing a case of Myopic strabismus fixus managed with loop myopexy. Chapter 19: 259-272.
10. Sharma P.Strabismus Simplified Second
diplopia gradually resolves. of surgical intervention. Pre and post-
Consecutive esotropia is secondary operative care is of outmost importance Edition. Chapter 7.
esotropia following surgical correction for good motor and sensory outcomes. 11. GilbertAL,KooEB,HeidaryG.Evaluation
for exotropia. It can happen following
surgery for an intermittent distance References and Management of Acute Acquired
exotropia. The initial management of Comitant Esotropia in Children. Semin
consecutive ET is nonsurgical includes 1. Cotter SA, Varma R, Tarczy-Hornoch Ophthalmol. 2017;32(1):8-13.
alternate occlusion, divergence K, et al. Risk factors associated with 12. Gunton KB. Vertical rectus
exercises or prisms16. If the ET persists childhood strabismus. Ophthalmology transpositions in sixth nerve palsies.
>6 months after nonsurgical treatments, 2011; 170-174. Curr Opin Ophthalmol. 2015
surgical treatment can be considered as Jul;26(5):366-70.
lateral rectus advancement or medial 2. Gunter K. von Noorden, Emilio C. 13. Kekunnaya R, Kraft S, Rao VB, Velez
rectus recession. Campos.—Binocular vision and ocular FG, Sachdeva V, Hunter DG. Surgical
Though very rare, it can occur following motility : theory and management of management of strabismus in Duane
slippage of lateral rectus where early strabismus Chapter 13, 6th ed : 311-348 retraction syndrome. J AAPOS. 2015
intervention is needed. Feb;19(1):63-9.
Esotropia in High myopia: also known 3. Rutstein RP. Update on accommodative 14. Mehendale RA, Dagi LR, Wu C, Ledoux
as myopic strabismus fixus- In esotropia. Optometry. 2008 D, Johnston S, Hunter DG. Superior
extremely high myopes progressive Aug;79(8):422-31. rectus transposition and medial rectus
convergent strabismus fixus occurs recession for Duane syndrome and sixth
due to superotemporal herniation of 4. Mulvihill A, MacCann A, Flitcroft nerve palsy. Arch Ophthalmol. 2012
the globe that causes displacement of I, O’Keefe M. Outcome in refractive Feb;130(2):195-201.
the lateral rectus and superior rectus17. accommodative esotropia. Br J 15. Hyndman J. Spasm of the Near Reflex:
This causes abduction and elevation Ophthalmol. 2000 Jul;84(7):746-749. Literature Review and Proposed
limitation with resultant esotropia and Management Strategy. J Binocul Vis
hypotropia complex. Surgical approach 5. Reddy AK, Freeman CH, Paysse EA, Ocul Motil. 2018 Jul-Sep;68(3):78-86.
aiming at restoration of the muscle Coats DK. A data-driven approach to 16. Kim DW, Han S, Kim US, Baek SH.
path is the preferred technique. This the management of accommodative Results of conservative management for
is achieved by loop myopexy wherein esotropia. Am J Ophthalmol. 2009 consecutive esotropia after intermittent
union of displaced muscles by silicone Sep;148(3):466-470. exotropia surgery. Eye (Lond). 2015
band or sutures with or without loop Jun;29(6):776-82.
myopexy sutures is performed with or 6. Pratt-Johnson JA, Tillson G. The 17. Yokoyama T et al. The mechanism of
without medial rectus recession18. management of esotropia with high development in progressive esotropia
AC/A ratio (convergence excess). J with high myopia. In: de Faber JT,
Conclusion Pediatr Ophthalmol Strabismus. 1985 editor. Transactions of the 26th meeting
Successful management of esotropia is Nov-Dec;22(6):238-242. European Strabismological Association.
actually guided by a thorough history, Barcelona: Swets & Zeitlinger; 2000. pp.
accurate refraction, proper orthoptic 7. Elliot S, Shafiq A. Interventions for 218–221.
examination and appropriate timing Infantile Esotropia. Cochrane Database 18. Yamaguchi M, Yokoyama T, Shiraki K.
Systematic Reviews 2005, Issue 1.Art No: Surgical procedure for correcting globe
CD004917. dislocation in highly myopic strabismus.
Am J Ophthalmol. 2010: 245-250.
8. Pediatric Eye Disease Investigator Group.
Spontaneous resolution of early-onset Corresponding Author:
esotropia: experience of the Congenital
Esotropia Observational Study. Am J Dr. Soveeta Rath
Ophthalmol. 2002 Jan;133(1):109-18. Dr. Shroff Charity Eye Hospital,
Darya Ganj, New Delhi, India.
9. Rosenbaum AL, Santiago AP.Clinical
strabismus management:principles
and surgical techniques. W B Saunders;

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 35

Subspeciality-Pediatric Ophthalmology

Intermittent Divergent Strabismus
- A Brief Review

Cinnam Shailaja MS, Sandra Ganesh DO, DNB, Kalpana Narendran DO, DNB
Aravind Eye Hospital, Coimbatore, India.

Intermittent divergent squint or either normal or just slightly higher Jampolsky have postulated that the
intermittent exotropia (IXT) is a form than normal in patients who have ability to suppress temporal vision
of exodeviation that is intermittently intermittent exotropia. allows the eyes to diverge.
controlled by fusional vergence 6. Genetics: A positive family history
mechanisms. Unlike a true phoria 4. Refractive errors: Refractive is often noted. Although heredity
it spontaneously breaks down into appears to play a role, the etiology
manifest exodeviation. IXT comprises errors through their effect on of exodeviations appears to
of about 50-90% of the cases of accommodation influence multifactorial.
exotropia1,2. It affects about 1% of the Most current theories on the etiology
general population. Exodeviations the position of the eyes. In of exodeviations combine the ideas of
occur more commonly in the Middle uncorrected myopia, less than Duane and Bielschowsky and revolve
East, subequatorial Africa and East Asia around the concept that exodeviations
than in the United States. normal accommodative effort is are caused by a combination of
required during near vision, thus mechanical and innervational factors.
Etiology
1. Innervational factors: According to causing decreased accommodative Clinical characteristics
convergence. According to Donders Age of onset: The onset of the majority of
Duanes, exodeviations occur as a exodeviations is shortly after birth. In
result of innervational imbalance this constant under stimulation Costanbader’s series of 472 patients with
between the active convergence of convergence may cause an intermittent exotropia, the deviation
and divergence mechanisms3. exodeviation to develop. However was present at birth in 204 individuals
2. Mechanical factors: Bielschowsky the role of myopia in the etiology of and appeared in 16 individuals at 6
stated that anomalous position of exodeviations is far less prominent months of age and in 72 individuals
rest of the eye contributes to the than that of hypermetropia in between 6-12 months of age. Exotropia
occurrence of exodeviations4. This esodeviations. If a high degree of developed after 5 years of age in only 24
abnormal position is influenced by hypermetropia is uncorrected, patients.
anatomical and mechanical factors such patients make no effort to
like shape and axis of the orbits, overcome the refractive error. An Sex distribution: Most studies describe a
inter pupillary distance and the size exodeviation may develop on the
of the globe, volume and viscosity basis of an under stimulated and
of retrobulbar tissues, length and thus under- active convergence
insertion of extra ocular muscles. mechanism that causes the AC/A
High prevalence of exodeviations ratio to remain low.
in patients with craniofacial
dysostosis (Crouzon’s disease) 5. Hemiretinal suppression: Knapp and
supports the theory of mechanical
factors. Classification Burian’s classification
3. AC/A ratio: Kushner had found
that approximately 60% patients Type Features Association
of true divergence excess have high
AC/A ratio5. Cooper and Medow Basic Distance deviation (DD) Normal tonic fusional,
concluded that the AC/A ratio is within 10 prism dioptres accommodative, proximal
(PD) of near deviation (ND) convergence

True divergence excess DD>10PD of ND even after 60% high AC/A ratio
patch test

Simulated divergence DD within 10 PD of ND Increased tonic fusional
excess after patch test convergence

Convergence ND>10 PD of DD
insufficiency

36 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Kushner’s classification with good stereopsis. Rarely a patient
will even have significant amblyopia.
Type Features The poor fusion in these cases is

Basic Distance and near measurements are equal associated with a predominance of the

Tenacious proximal fusion DD initially exceeds ND, but the ND increases tropia phase.

High AC/A ratio after 60 min of patch test Clinical evaluation
Proximal convergence DD exceeds ND and high AC/A ratio is present A) Assessment of control: It is done to
DD exceeds ND even after 60 min of patching, obtain a baseline evaluation as well as to
AC/A ratio is normal monitor deterioration and progression.

Low AC/A ratio ND exceeds DD. Low AC/A ratio Subjective methods: Three scoring
Fusional convergence ND exceeds DD, patients have poor fusional systems are available for assessing
insufficiency convergence amplitudes control in IXT.
Pseudo convergence ND exceeds DD, but DD increases with 60 min of
insufficiency patching 1. New Castle control scoring method
(Table 3) - Reliable method for
grading the severity of IXT. It
commonly reported. It is because bright incorporates both Home control
female preponderance for IXT light dazzles the retina so that fusion is
disrupted and the deviation becomes and Clinic control criteria in to a
Refractive errors: The distribution of manifest. Child closes one eye to avoid single scale. The total score is a sum
refractive errors in exotropes is similar diplopia. It is seen in patients who of home control and office control
to that of non strabismic population. for distance and near. A patient

Natural history: IXT is usually preceeded maintain a delicate balance between with a score of 4 or more is unlikely
by a stage of exophoria. It slowly exophoria and intermittent exotropia. to attain cure without surgery10.

deteriorates into intermittent and Sensory adaptations: In majority of 2. Mayo clinic exotropia score: (Table 4)
constant exotropia as suppression patients, during the phoric phase The score can vary from 0-10.
develops. Jampolsky considered the eyes are perfectly aligned and
suppression to be the key that unlocks the patient has bifoveal fusion with 3. Mohney Holmes control score:
fusion mechansism6. Factors that excellent stereoacuity ranging between (Table 5) It is an office control
influence progression are the decrease 40 and 50 s arc. This is because the assessment method11. The patient is
in tonic convergence with advancing eyes are well aligned in early infancy observed for a sample period of 30
age, development of suppression, when the critical binocular cortical sec and scoring is done as follows:
gradual decrease in accommodative connections are being established.
power and increasing divergence of the During the tropic phase patients will Objective methods
orbits with advancing age. Von noorden show large hemiretinal or regional
followed 51 patients for up to 3.5 years suppression of the temporal retina.8 Distance Stereoacuity: It provides an
and reported progression in 75%, objective assessment of both control
no change occurred in 9% and 16% Anomalous retinal correspondence of the deviation and deterioration of
improved without therapy7. in the tropia phase and normal retinal fusion. Normal distance stereoacuity
correspondence in the phoria phase indicates good control with little or
no suppression. Distance Randot Test
is based on new polaroid vectograph.
Symptoms and signs: Patients with IXT have been demonstrated in some It is very sensitive to disturbance of
rarely complain of any symptoms. patients9. A minority of patients with stereoacuity and control can be well
It is usually first observed by parents IXT are primary monofixators and do correlated with performance in this
as spontaneous outward drifting not develop normal bifoveal fusion

of one eye when the child is tired,
sick or daydreaming. Absence of
symptoms in children is because of Home control Clinic control
the well developed suppression that
eliminates diplopia. Older children and Deviation of eye or monocular Realignment after cover test for distance
adults on the other hand may report closure and near

Never 0 Immediate realignment after cover test 0

asthenopic symptoms like eye strain, <50% of the time for distance 1 Realignment after blinking or refixation 1
difficulties with prolonged periods of
reading, blurring of vision, headache >50% of the time for distance 2 No realignment after cover test 2
and diplopia. Diplophotophobia is >50% of the time for distance 3 Spontaneously manifest exotropia 3
and also for near

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 37

Subspeciality-Pediatric Ophthalmology

Cover test for distance and near Score disparity postoperatively and may
Never exotropic unless dissociated; recovery in <1 second 0 require bifocal glasses.
Never exotropic unless dissociated; recovery in 1-5 seconds 1
Never exotropic unless dissociated; recovery in >5 seconds 2 Angle of deviation in lateral gaze: When
Exotropia less than 50% of the time before dissociation 3 the amount of exotropia decreases
Exotropia more than 50% of the time before dissociation 4 in lateroversion as compared to the
Constant exotropia 5 primary gaze it is called lateral gaze
incomitance. A difference of 20% or
Description Control score more is considered to be significant.
Constant XT during a 30 sec observation period (before 5 Reduction of surgical dosage is needed
dissociation) when there is lateral gaze incomitance
XT > 50% of the time during a 30 sec observation period 4 in order to avoid overcorrections.
(before dissociation)
XT < 50% of the time during a 30 sec observation period 3 Treatment
No XT unless dissociated, recovery in > 5 sec 2 The treatment of intermittent exotropia
No XT unless dissociated, recovery in 1-5 sec 1 is generally surgical. However, certain
Pure phoria: <1 sec recovery after 10 sec dissociation 0 nonsurgical measures may be indicated
to create optimal sensory conditions
test12. dominant eye is occluded doesn’t effect before surgery or when surgery must be
the test results. postponed. The functional prognosis is
Near Stereoacuity: It does not correlate poor when constant exotropia occurs
well with the degree of control in IXT Far Distance Measurement: This is done early in infancy and when there is no
and performance in this test is only by having the patient fixate well past history of intermittency. In such cases
minimally affected by surgery. 20 feet distance so as to relax proximal preoperative treatment is not required.
convergence. Combining the patch
B) Measuring the Angle of Deviation: test and far distance measurement Nonsurgical treatment
can reduce the under-correction and 1. Correction of refractive errors:
Measurement by routine alternate improve overall surgical results.
cover prism test may not be sufficient Significant refractive errors
to uncover the full angle due to variable + 3.0 D Near Add Test (Lens Gradient especially astigmatism and
nature of the deviation in IXT. Prolonged Method): Helps to diagnose true anisometropia should be corrected
alternate cover testing should be done divergence excess due to high AC/A to create sharp retinal images,
to mitigate tonic fusional convergence. Ratio. It should be done in patients who which in turn increase the
have a near distance disparity of 10- stimulus to fuse. Full correction
Patch Test: This test is done to unmask 15 prism dioptres or more after patch is advisable in myopic patients to
full amount of deviation at near fixation test. After the patch test while the eyes maintain active accommodative
and thus differentiate simulated are still dissociated, the deviation is convergence. Correction of
divergence excess from true divergence remeasured at near with +3.0D lens hypermetropia should be decided
excess. Momentary disruption of add. It suspends accommodation and on case to case basis depending
fusion during the prism and alternate thus accommodative convergence. This on age of the patient, degree of
cover test is insufficient to break the will have little influence in a patient hypermetropia and AC/A ratio.
powerful fusional convergence. Hence with an exodeviation and a low AC/A 2. Over correcting minus lenses:
monocular patching for 30-45 min is ratio. On the other hand, with a high It is based on stimulating
done to disrupt the fusion and prism AC/A ratio, if the deviation is measured accommodative convergence thus
cover test is repeated. Momentary through +3.00 lenses, it will increase controlling the exodeviation. It
binocular stimulation may reinstate substantially at near fixation. If the is useful in patients with high
the mechanism by which the patient near deviation increases by 20 prism AC/A ratio. Additional minus
controls the deviation. Therefore the dioptres or more the diagnosis of high power lenses (-1D to -5D) over
fellow eye must be occluded before the AC/A Ratio true divergence excess type the cycloplegic refraction are
patch is removed and then proceeded in intermittent exotropia is made. These prescribed full time. Minimum
the usual manner with the prism cover patients continue to have near distance minus power that a child can
test. Whether the dominant or non tolerate and does not compromise
the child’s vision while providing
the best control over the deviation
are given. It is used as a temporising
measure to improve fusion so

38 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

that surgery can be safely delayed improving health related quality of results in better alignment and lower
without loss of binocularity13,14. life19. chances of recurrence of exotropia
3. Prism therapy: Base in prisms are compared with BLR, especially in
used to improve fusional control as Age at surgery: Surgery for IXT is the presence of ocular dominance22.
a temporary therapy either pre or better delayed in young visually However recent studies have shown
postoperatively. immature children in order to avoid that there is no significant difference
4. Part time occlusion therapy: By overcorrection. Consecutive esotropia between symmetrical or asymmetrical
occluding the dominant eye the in a visually immature child results surgery23. Infact more recent studies
patient is forced to use the non in loss of binocularity and amblyopia. with longer followup show that BLR has
preferred eye, thus providing anti Hence usually surgery is delayed till better long term outcome with greater
suppression therapy. Alternate 4-6 years of age. In the interim period stability24. Also symmetrical surgery
eye occlusion can be done in small binocularity can be reinforced with is preferred because large amounts
angle IXT in young children in overcorrecting minus lenses or prisms, of R&R produces lateral incomitance
order to delay the surgery15,16. suppression can be prevented by with diplopia in side gaze. The dosage
5. Orthoptics: Active antisuppression alternate occlusion.20 Surgery at an of surgery should be based on the full
exercises and diplopia awareness early age should be considered only if distance deviation after patch test.
techniques can be advised for there is rapid deterioration of fusional Augmented bilateral LR recession
patients with suppression. The aim control inspite of non surgical therapy (increasing the surgical dosage by
is to make the patient aware of the or if the deviation is constant. 1-2.5 mm for each LR or increasing the
deviation and improve control. target angle by 5 PD) and augmented
Knapps has summarised that Angle of deviation: The angle of primary R&R (increasing the dosage of only
orthoptics can’t be a substitute to exodeviations generally exceeds 20 PD, MR resection by 1 mm) improved
surgery in IXT rather a supplement small angle exodeviations are rare. If for long term results with no significant
to it. Convergence exercises functional reasons surgery is indicated difference in over correction25,26. Greater
will be helpful for patients with the deviation should atleast measure 15 preoperative deviation especially if >40
convergence insufficiency type of PD. PD is associated with poor outcomes.
IXT17. Exodeviations lying within the grey
Goals of surgery: Most clinicians agree zone which pose the dilemma of
Surgical treatment that a small surgical overcorrection whether to add an extra muscle have
Indications for surgery : Surgery is is desirable since functional results unpredictable outcomes27.
indicated for preservation or restoration will be better in terms of stimulating
of binocular vision. The need for surgery fusion and the alignment will be more True divergence excess: Surgical outcomes
is determined by the state of fusional stable. But more recent studies show in true divergence excess have been
control, the size of deviation and age of that the results of initial overcorrection found to be better than basic and BLR
the patient. Signs of progression that are variable and unpredictable21. It has been preferred over R&R for this
warrant surgery include:- should be avoided in visually immature type. Distance deviation after prolonged
children. occlusion test should be considered as
1. Gradual loss of fusional control as the target angle for surgical correction.
evidenced by increasing frequency Choice of procedure: Classic approach Patients with high AC/A ratio have
of tropia phase18 regarding the procedure of choice in significant risk of overcorrection with
IXT are as follows: consecutive esotropia for near if distance
2. Increase in the size of basic measurement is taken as target. It is
deviation 1. True divergence excess - Recession best to operate for a deviation between
of both lateral rectus muscles (BLR) near and distance measurements.
3. Development of suppression as Fadens procedure for medial rectus
evidenced by absence of diplopia 2. Basic exotropia or simulated can be added to BLR in order to prevent
during manifest phase divergence excess type of IX - postoperative overcorrection for near.
Recession of lateral rectus with Posterior pulley fixation of MR along
4. Decrease of distance stereoacuity resection of ipsilateral medial with BLRc has been described as a
5. Development of secondary rectus muscle on the non dominant newer procedure in similar cases with
eye (R&R) good outcomes28.
convergence insufficiency
An important non clinical indication 3. Convergence insufficiency - Convergence insufficiency: It is best
for surgery is to improve the cosmesis. Bilateral medial rectus resection treated by convergence exercises with
Studies have shown that strabismus (BMR) or without prisms. If orthoptic exercises
surgery has significant effect on self
esteem and confidence of the patients Basic or simulated divergence excess: Some
studies comparing unilateral R&R and
bilateral LR recession state that R&R

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 39

Subspeciality-Pediatric Ophthalmology

fail to alleviate symptoms, surgery in postoperative week will probably 10. Buck D, Hatt SR, Haggerty H, Hrisos
the form of one or both medial rectus not improve and most will require S, Strong NP, Steen NI et al. The use
resections is considered. Various other additional surgery. It is best to wait 6-8 of the Newcastle control score in the
procedures like slanted MR resection weeks before reoperating. Re recession management of intermittent exotropia.
(with greater resection of lower fibres of both lateral rectus muscles is done Br J Ophthalmol 2007;91:215-8.
for near deviation and lesser resection if the primary surgery was bilateral
of superior fibres), slanted bilateral recessions of 6.0 mm or less. If the 11. Mohney BG, Holmes JM. An office-
LR recessions, adjustable sutures are primary recessions were greater than based scale for assessing control in
described with variable success rates.29 6.0 mm, bilateral MR resections are intermittent exotropia. Strabismus.
performed. This is done cautiously 2006 Sep;14(3):147-50.
A and V patterns and oblique as over corrections are common after
overactions: Simultaneous surgery on resecting against a large recession. 12. Adams WE, Hatt SR, Haggerty H, Buck D.
the obliques if dysfunction is present, Improvement in distance stereoacuity
or vertical offsetting of the horizontal Prognosis following surgery for intermittent
muscles for A- and V-patterns is done. Surgical success depends on the period exotropia. J AAPOS 2008;12:141-4.
Significant alteration in the amount of followup with higher incidence
of horizontal surgery is not needed in of under corrections with higher 13. Rowe, F., Noonan, C., Freeman, G. et al.
such cases. Inferior oblique weakening followup30. Various factors affecting Intervention for intermittent distance
procedures are safe in patients with surgical outcomes include age of the exotropia with overcorrecting minus
bifoveal fusion and IXT but performing patient, sensory status, preoperative lenses. Eye 23, 320–325 (2009)
superior oblique tenotomies or angle of deviation, control and early
tenectomies may result in a consecutive post operative angle. 14. Chen AM, Holmes JM, Chandler DL,
superior oblique paresis with torsional Pediatric Eye Disease Investigator
diplopia. Hence alternative procedures References Group: A randomized trial evaluating
like infra placement of the lateral rectus 1. Govindan M, Mohney BG, Diehl short-term effectiveness of over-minus
muscles or the Wright superior oblique lens therapy in children 3 to 6 years
tendon expander are preferred. NN, Burke JP. Incidence and type of of age with intermittent exotropia.
childhood exotropia: a population based Ophthalmology 2016
Management of under corrections study. Ophthalmology 2005;112:104-8.
2. Von Noorden GK. Binocular Vision 15. Pediatric Eye Disease Investigator
Management of overcorrections: Small and Motility. Theory and Management Group: A randomized trial comparing
amounts of overcorrection of about of Strabismus 5th ed Mosby: St Louis part-time patching with observation
8-10 PD is desirable as there is a 1996;343. for children 3 to 10 years of age with
tendency of the eyes to drift with time. 3. Duane A: A new classification of the intermittent exotropia. Ophthalmology
Small amount of consecutive esotropia motor anomalies of the eyes based 2014; 121: 2299–2310.
may completely disappear so no upon physiological principles, together
therapy is given for the first 2 weeks. If with their symptoms, diagnosis 16. Pediatric Eye Disease Investigator
diplopia persists after 2 weeks, miotics and treatment. Ann Ophthalmol Group: A randomized trial comparing
or bifocals may be given. In visually Otolaryngol 5:969, 1896; 6:84,247, 1897. part-time patching with observation for
immature children where fusion must 4. Bielschowsky A: Divergence excess. intermittent exotropia in children 12 to
be maintained base out prisms are Arch Ophthalmol 12:157, 1934. 35 months of age. Ophthalmology 2015;
preferable. For large angle or persisting 5. Kushner BJ: Exotropic deviations: A 122: 1718–1725.
consecutive esotropia resurgery should functional classification and approach
be considered. Bimedial recessions are to treatment. Am Ortho J 1988;38:81-93. 17. Scheiman M, Mitchell GL, Cotter S,
usually the procedure of choice for a 6. Jampolsky A: Ocular deviations. Int Cooper J, Kulp M, Rouse M, Borsting E,
consecutive esotropia, especially if the Ophthalmol Clin 4:567, 1964. London R, Wensveen J. A randomized
esotropia is greater at near. 7. Noorden GK von: Some aspects clinical trial of treatments for
of exotropia. Presented at Wilmer convergence insufficiency in children.
Advancement of lateral rectus is Residents’ Association, Johns Hopkins Arch Ophthal- mol 2005;123:14–24.
indicated if there is limited adduction Hospi- tal, Baltimore, April 26, 1966.
or lateral incomitance that is consistent 8. Nawratzi I, Jampolsky A. A regional 18. Wilson ME Jr. Intermittent exotropia:
with a slipped muscle. hemiretinal difference in amblyopia. when to observe and when to treat. J
Am Ophthalmol ;46:339. AAPOS. 2011 Dec;15(6):518.
Management of under corrections: 9. BurianHM. The sensorial retinal
Patients with a residual exotropia relationship in comitant strabismus. 19. Hatt SR et al. Associations between
greater than 10 PD after the first Arch Ophthalmol 1947;337:336. health-related quality of life and
the decision to perform surgery for
childhood intermittent exotropia.
Ophthalmology. 2014 Apr;121(4):883-8.

20. Kushner BJ. Conservative management
of intermittent exotropia to defer
or avoid surgery. J AAPOS. 2019
Oct;23(5):256.e1-256.e6.

21. Pineles SL, Deitz LW, Velez FG.
Postoperative outcomes of patients
initially overcorrected for intermittent

40 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

exotropia. J AAPOS. 2011 Dec;15(6):527- Bilateral lateral rectus recession in Eye 2018;32:693–700.
31. children with intermittent exotropia. 30. Ekdawi NS, Nusz KJ, Diehl NN, et al.
Am J Ophthalmol 2016;163:11–17.
22. Jeoung JW, Lee MJ, Hwang JM. Bilateral Postoperative outcomes in children
lateral rectus recession versus unilateral 26. Kim J-S, Yang HK, Hwang J-M. Long- with intermittent exotropia from
recess-resect procedure for exotropia term outcomes of augmented unilateral a population-based cohort. J Aapos
with a dominant eye. Am J Ophthalmol recess-resect procedure in children 2009;13:4–7.
2006;141:683–8. with intermittent exotropia. Plos One
2017;12:e0184863. Corresponding Author:
23. Donahue SP, Chandler DL, Holmes JM,
et al. A randomized trial comparing 27. Chougule P, Kekunnaya R. Surgical Dr. Sandra C. Ganesh DO, DNB
Bilateral lateral rectus recession management of intermittent exotropia: Aravind Eye Hospital,
versus unilateral recess and Resect do we have an answer for all? BMJ Open Coimbatore, India
for Basic-Type intermittent exotropia. Ophthalmology 2019;4:e000243.
Ophthalmology 2018;0.
28. Choi HY, Jung JH. Bilateral lateral rectus
24. Yang X, Man TT, Tian QX, et al. Long- muscle recession with medial rectus
term postoperative outcomes of pulley fixation for divergence excess
bilateral lateral rectus recession vs intermittent exotropia with high Ac/A
unilateral recession-resection for ratio. J Aapos 2013;17:266–8.
intermittent exotropia. Int J Ophthalmol
2014;7:1043–7. 29. Farid MF, Abdelbaset EA. Surgical
outcomes of three different surgical
25. Kim H, Yang HK, Hwang JM. Long- techniques for treatment of convergence
term surgical outcomes of augmented insufficiency intermittent exotropia.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 41

Subspeciality-Pediatric Ophthalmology

Congenital Corneal Opacities

Mohamed Ibrahime Asif, Rahul Kumar Bafna, Namrata Sharma
Cornea and Refractives Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences. AIIMS, New Delhi, India.

Congenital corneal opacities could be Classification Primary corneal disease
hereditary, developmental or infectious 1. STUMPED classification1 (From
causes. It can be unilateral/ bilateral; Waring GO, Rodrigues MM. Congenital i) Corneal dystrophies
isolated/associated with ocular or and neonatal corneal abnormalities). • CHED
systemic abnormalities. Though rare, • PPCD
diagnosing them is very important Table 1 • CHSD
to predict the natural course of the • XECD
disorder, take appropriate medical and S Sclerocornea
surgical therapy as required considering T Tears in Descemet membrane ii) Corneal dermoid
the amblyopic age group, to provide iii) Peripheral sclerocornea
genetic counseling to the parents and to (congenital glaucoma, birth iv) CYP1B1 cytopathy
diagnose associated systemic disorders trauma) Secondary corneal disease
and treat them. U Ulcers (viral keratitis, bacterial
keratitis) 1. Congenital
History and Examination M Metabolic (mucopolysaccharidoses, • Kerato - irido - lenticular
A detailed history and examination mucolipidoses) dysgenesis
would be helpful in diagnosing the P Posterior corneal defect (Peters • Irido-trabecular dysgenesis
condition. anomaly, Posterior keratoconus) • Primary congenital glaucoma
Obstetric history- regarding any drug E Endothelial dystrophy (CHED, • Intracorneal cyst
intake or any gestationally acquired PPCD)
infections like rubella, varicella. History D Dermoid 2. Acquired
of any vaginal or cervical infections 2. New classification of neonatal corneal • Trauma
for the mother especially herpetic/ opacities (Nichal KK2) • Infection
gonococcal infections. Family history
of any ocular disorder in paternal/ Table 2: Differentiating features between birth trauma and congenital
maternal side/ any other previous glaucoma
delivery.
Examination could be performed at bed Birth trauma Congenital glaucoma
side as slit lamp examination would not
be possible in many cases. Handheld slit Tears in the DM are vertical/oblique- Tears in the DM are usually horizontal/
lamp/ torchlight could be used for bed due to instrumental delivery (forceps concentric to limbus (Haab striae)
side examination. However, a complete delivery)
examination is accomplished under
general anesthesia (EUA). During EUA, Corneal diameter is normal Corneal diameter could be enlarged
ultrasonography (A scan and B scan) (buphthalmos)
and ultrasound biomicroscopy (UBM)
should be performed. Corneal diameter, Intraocular pressure normal Elevated IOP
intraocular pressure, gonioscopy
(if possible) should be performed. Corneal edema appears in the Corneal edema appears few weeks after
Corneal examination with fluorescein immediate post-partum period birth
staining and cobalt blue light should be
performed. Optic nerve head is unaffected Optic nerve head cupping could be
present

Left eye more frequently affected due Either/ both eyes could be affected
to common head crowning position

Usually less incidence of photophobia Photophobia commonly present

42 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Table 3: Differentiating features between various mucopolysaccharidosis

Hurler/ Gragoylism Maroteaux- Sheie Morquio Hunter
Lamy

Hurler/ Gragoylism Maroteaux-Lamy Sheie Morquio Hunter

Inheritance AR AR AR AR XLR

Deficiency Alpha-1-iduronidase Arylsulfatase B Alpha-1- Galactosamine-6- Iduronate sulphatase
iduronidase sulphate sulphatase/
beta galactosidase

Onset Within first few years Within first few From birth Usually after 10 Doesn’t present as
years but decrease years old corneal opacity
vision by 2nd
decade

Ocular Diffuse punctate stromal Punctate corneal Thickened or Corneal opacities Corneal opacity
opacities not involving opacities almost edematous seen in few. (10%) might occur later in
epithelium and always present cornea, life in mild form
endothelium. Significant at birth, narrow prominent in
corneal clouding angle glaucoma the periphery.
Associated
glaucoma

Systemic Mental retardation, large Mild facial Claw hand Dwarfism, joint Clinically appears
head with abnormal abnormalities, deformities, laxity, valvular like Hurler but
facies, dwarfism, joint skeletal changes valvular (aortic valve) heart deafness and cardiac
contractures, hepato- like kyphosis, (aortic valve) diseases defects are common
splenomegaly, deafness, genu valgum, heart diseases.
hirsutism, cardiac and protuberant They have
CNS defects sternum, normal
hydrocephalus intelligence,
height and life
expectancy

Table 4: Ocular features of various mucolipidosis thickness appearing similar to sclera
and it is prominent in the peripheral
MLS-I These three types do not cause any severe corneal cornea than the central. The cornea
MLS-II (I cell disease) diseases and do not usually require any ocular is flat with keratometry usually less
treatment. Mild opacification seen in less than 20% in
type I, 40% in type II and almost all cases of type III than 43D. Ocular associations include
microcornea, microphthalmos,
MLS-III This type is always associated with significant glaucoma, coloboma, aniridia,
MLS-IV congenital corneal opacity. Episodic eye pain is seen blue sclera, ectopia lentis, cataract
due to accumulation of abnormal material in the
epithelium leading to surface irregularities. Other and systemic associations include
ocular findings include retinal degeneration, optic cerebellar anomalies, Dandy-Walker
atrophy, cataract, attenuated vessels. They have cyst, cryptorchidism, ear deformities,
profound psychomotor retardation without skeletal/ polydactyly, osteogenesis imperfecta
facial deformity. and various other syndromes.

• Metabolic KERA gene), usually bilateral and Histologically, the corneal stroma
Disorders asymmetric scleralization of the appears like stroma due to irregular
1. Sclerocornea (cornea plana): It is peripheral or entire cornea which may arrangement of thickened collagen
non-progressive, sporadic (can be occur alone or in association with other fibers, decrease in the diameter of
familial/ AD/ AR form- mutation in ocular anomalies. Opacification is collagen fibrils in the posterior stroma
smooth, white, vascular involving full in contrast to the normal cornea and
attenuated or absent DM.

UBM and ASOCT could be useful to

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 43

Subspeciality-Pediatric Ophthalmology

Table 5: Types of Peter anomaly 3. Ulcers
Type 1 Peter
Corneal opacity along with Type 2 Peter • Viral- all infections of herpes in
iridocorneal adhesions (lens is usually Type 1+ lens abnormalities the neonatal period should be
clear) (keratolenticular adherence, treated with systemic acyclovir
Predominantly unilateral involvement cataractous lens) 30mg/kg/day for 10 days apart from
with less dense opacity topical antivirals and cycloplegics.
Associated ocular anomalies- Predominantly bilateral with denser Topical should be given till re-
microcornea, sclerocornea, infantile opacity epithelialization but no longer than
glaucoma, vitreoretinal abnormalities 14 days.
rare Associated ocular anomalies-
Systemic associations- rare microphthalmia with PHPV, • Bacterial- rare to appear at birth.
microcornea, sclerocornea, cornea
Good visual potential plana, coloboma, aniridia, optic Neisseria gonorrhoeae can produce
atrophy serious ocular and systemic
Systemic associations- poly/ complications. They present as
syndactyly, Wilms tumor, craniofacial severe unilateral conjunctivitis
dysplasia, cardiac defects, CNS within few hours to 2-3 days
anomalies, pulmonary hypoplasia, ear with associated lid edema, severe
abnormalities chemosis, serosanguineous
discharge and pseudo membrane
Poorer compared to type 1 formation. Systemic treatment

Table 6: Differentiating features between Peter and Sclerocornea is necessary to avoid systemic
complications. Previously i.v
Peter Sclerocornea aqueous penicillin G 100000 units/

Opacity involves the central cornea Opacity more pronounced peripherally kg/day in divided doses for 7 days,
and its localized than the central cornea. Variant can however, due to resistance a single
involve the total cornea i.m dose of 125mg ceftriaxone
became the recommended
Iris strands attach to the posterior Generally absent. Could be seen if treatment. Cefotaxime 25mg/kg
corneal defect/ leukoma associated with anterior chamber i.v or i.m every 8-12 hours for 7
cleavage anomalies
days can also be given. Oral dose of
Mostly occurrence is sporadic. AR/AD sporadic (can be familial/ AD/ AR form) fluoroquinolones is also effective
have been observed. Gene involved is KERA gene but have potential disadvantage
Genes involved PITX2, FOXC1,
CYP1B1, PAX6. of inducing antibiotic resistance.
In addition to systemic treatment,
Better prognosis with PK compared to Worst prognosis than Peter8
Sclerocornea hourly irrigation of the eyes with
saline, topical fluoroquinolones are
used in the early treatment.

look for any associated structural • Sclerocornea associated with 4. Metabolic diseases
abnormalities, identification of pupil anterior chamber cleavage
and thereby facilitating surgical anomalies; • Mucopolysaccharidosis
planning. Surgery should be planned
if significant central vision of both • Total sclerocornea (most common • Mucolipidosis
eyes is affected with relatively normal form)
other ocular structures as the outcomes • Tyrosinemia- AR disorder due to
of the surgery are very poor. Usually Penetrating grafts carry very poor visual defect in soluble hepatic cytosol
penetrating grafts are required, however outcomes in these cases. tyrosine aminotransferase
the prognosis for a clear graft poorer (chromosome 16). Only type II
than Peter anomaly. 2. Tears in endothelium and Descemet (Richner-Hanhart syndrome) is
membrane associated with corneal opacity. It
Waring and Rodrigues classified is characterized by a triad of mental
sclerocornea into 4 groups 3: Left eye more frequently affected due retardation, dendriform lesions of
to common head crowning position the cornea, hyperkeratotic lesions
• Isolated peripheral sclerocornea; Either/ both eyes could be affected of palms and soles. It usually
• Sclerocornea plana; appears in first few months of age
Usually less incidence of photophobia and it is important to distinguish
Photophobia commonly present this from herpes keratitis. Bilateral

44 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Table 7: Differentiating features between types of endothelial dystrophies

Congenital Hereditary Endothelial Posterior Polymorphous Corneal Congenital Stromal Corneal Dystrophy
Dystrophy Dystrophy Corneal opacity- central with feathery
appearance. Corneal thickness is normal
Diffuse, non-bullous severe corneal Lesser corneal edema with usually Corneal changes are present at birth and
edema (thickness increased by 2-3 normal corneal thickness are stationary
times) leading to bluish-gray ground
glass appearance Autosomal dominant

Corneal clouding present at birth or Onset in first or second decade with
shortly after slow progression of corneal clouding
over a decade

No associated symptoms like epiphora/ Usually present with epiphora
photophobia and photophobia with subsequent
developing clouding of cornea

Autosomal recessive Autosomal dominant

Table 8: Differential diagnosis of dermoids

Dermoid Keloid Salzmann nodules
They are multiple, bluish-white
They are yellowish-white elevated They are chalky white solid masses superficial corneal nodules which are
nodule containing hair follicles, with glistening appearance and the usually seen in mid periphery.
sebaceous glands, sweat glands, bones, texture is usually gelatinous. They are not present at birth and are
cartilages or teeth, situated in the Can be central with often associated usually related to associated ocular
inferotemporal limbus usually. satellite lesions. inflammation like VKC, trachoma,
Definitive diagnosis made with corneal keratoconus, EBMD or corneal surgery)
biopsy

involvement, morphology (lack of They start anteriorly and in earliest and most consistent ocular
terminal bulbs and poor staining periphery and later involve the changes seen. In advanced cases,
of the lesion, consistent infero- entire cornea5, leading to irritation, fine, curvy or whorl-like superficial
central location), normal corneal pain and photophobia. corneal opacity are seen, known
sensitivity, lack of response to as cornea verticillata. They are not
anti-viral treatment (persisting Lubricating eye drops and present at birth but can occur as
longer than 6 weeks), exacerbation therapeutic bandage contact early as six months of age. Enzyme
with increased protein intake and lenses could be useful in providing replacement therapy is available for
systemic associations should rise symptomatic relief. Topical Fabry disease.
the suspicion of tyrosinemia4. cysteamine solution 0.55% • Gangliosidoses
Child should be advised tyrosine and administered every 1-2 hourly could 5. Posterior corneal defect
phenylamine restricted diet which be useful in dissolving the cystine
would resolve corneal lesions. accumulated. It is also useful post- • Peter anomaly- congenital disorder
PK to prevent re-deposition. with a central leukomatous
• Cystinosis- AR disorder caused corneal opacity with associated
by mutation in CTNS gene in • Fabry disease- XLR disorder due defect in posterior stroma, DM and
chromosome 17, leading to defect to lack of the enzyme alpha endothelium. It is usually bilateral
in the cystine transport with galactosidase A leading to (80%) and asymmetrical. There
intracellular accumulation of deposition of sphingolipids within would be associated defects in angle
free cystine, thereby resulting in lysosomes. It is characterized by development leading to increased
crystalline deposition in various angiokeratomas of skin along with incidence of glaucoma (50-80%).
tissues (eye, kidneys, bone multisystem involvement. Ocular
marrow, lymph nodes). These manifestations include corneal Peter-plus syndrome- Peter +
needle shaped crystals are seen in opacities (90%), conjunctival vessel mental retardation, short stature,
cornea (epithelium, stroma and tortuosity (60%), retinal vessel brachymorphy, ear abnormalities, cleft
endothelium) and conjunctiva. tortuosity, cataract (Fabry cataract- lip and palate.
spoke like posterior capsular
cataract).6 Corneal changes are

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 45

Subspeciality-Pediatric Ophthalmology

Krause-Kivlin syndrome- Peter + They are congenital overgrowth of 4. Charlton KH, Binder PS, Wozniak L,
developmental delay, retarded skeletal normal tissues in an abnormal location Digby DJ. Pseudodendritic keratitis and
maturity with disproportionate short (choristoma). Three grades of dermoid systemic tyrosinemia. Ophthalmology.
stature and facial abnormalities choristoma have been described based 1981 Apr 1;88(4):355-60.
on the extent of involvement (Mann
Hence, patients of Peter should be grading)10: 5. Cotran PR, Bajart AM. Congenital corneal
screened for systemic malformations opacities. International ophthalmology
especially midline body structures Grade1: most frequent type; it is single, clinics. 1992 Jan 1;32(1):93-105.
like heart and pituitary gland.7 small usually less than 5mm diameter
Definite ocular management includes in the inferotemporal limbus generally 6. Fledelius HC, Sandfeld L, Rasmussen
penetrating keratoplasty though in involving superficial structures. It is ÅK, Madsen CV, Feldt‐Rasmussen
few cases with small localized opacity present at birth and may enlarge during U. Ophthalmic experience over 10
attempt of optical iridectomy could be puberty. One-third cases could have years in an observational nationwide
done. Outcomes of PK are better in type associated syndrome complex such as Danish cohort of Fabry patients with
1 Peter than in type 2.8 Goldenhar syndrome (triad of epibulbar access to enzyme replacement. Acta
dermoid, preauricular appendages and ophthalmologica. 2015 May;93(3):258-
• Posterior keratoconus- Uncommon, pre-tragal fistulas) 64.
mostly unilateral, sporadic and
non-progressive characterized by Grade 2: larger covering a part or entire 7. Traboulsi EI, Maumenee IH.
local conical, internal protrusion cornea but does not involve DM or Peters’ anomaly and associated
of the posterior corneal curvature endothelium congenital malformations. Archives
with associated stromal thinning. of Ophthalmology. 1992 Dec
It could be mildest variant of Peter Grade 3: most severe type; rarest; 1;110(12):1739-42.
anomaly with no relationship to anterior segment is involved in this type
anterior keratoconus 8. Kim YW, Choi HJ, Kim MK, Wee WR,
Management- Grade 1 dermoid- Yu YS, Oh JY. Clinical outcome of
• Congenital anterior staphyloma- conservatively managed (except penetrating keratoplasty in patients
it is characterized by protruding, when induced irregular astigmatism, 5 years or younger: peters anomaly
ectatic congenital corneal opacity amblyopia unresponsive to versus sclerocornea. Cornea. 2013 Nov
of one or both eyes. The lesion can conservative management, progressive 1;32(11):1432-6.
be vascularized and the posterior dellen, inadequate lid closure, aesthesis).
portions of these ectatic thin corneas Surgical intervention from simple 9. Busin M, Beltz J, Scorcia V. Descemet-
are lined by pigment epithelium of excision to lamellar/ penetrating grafts stripping automated endothelial
the atrophic iris. Pathogenesis is might be required for larger dermoids. keratoplasty for congenital hereditary
unknown though it is thought to be endothelial dystrophy. Archives
secondary to intrauterine infections References of ophthalmology. 2011 Sep
or developmental abnormality. 12;129(9):1140-6.
1. Waring GO, Rodrigues MM. Congenital
6. Endothelial dystrophy and neonatal corneal abnormalities. 10. Mann I. Developmental abnormalities
Tasman W, Jaeger E. Duane’s of the eye. CUP Archive; 1957.
Management- DSAEK could be ophthalmology, CD-Rom. Lippincott
performed in cases of CHED/ PPCD if Williams & Wilkins: Philadelphia; 2002 Corresponding Author:
there is no significant stromal scarring
in the visual axis. Performing surgery 2. Nischal KK. A new approach to the Dr. Mohamed Ibrahime Asif
at early age could improve visual classification of neonatal corneal Cornea and Refractives Services,
development and potentially avoid opacities. Current opinion in Dr. Rajendra Prasad Centre for Ophthalmic
amblyopia9. If significant stromal ophthalmology. 2012 Sep 1;23(5):344-54. Sciences. AIIMS, New Delhi, India.
scarring is present in visual axis, full
thickness graft is preferred. 3. Waring 3rd GO, Rodrigues MM.
Ultrastructure and successful
7. Dermoid keratoplasty of sclerocornea in Mietens’
syndrome. American journal of
ophthalmology. 1980 Oct;90(4):469.

46 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

Management of Periocular and
Orbital Vascular Lesions in
Children

Karthika Bhaskaran, Deepshekhar Das, Prof. Mandeep S Bajaj
Oculoplasty, Orbital Diseases, Lacrimal Disorders and Ocular Tumors Services, Dr. Rajendra Prasad Centre for Ophthalmic Sciences.
AIIMS, New Delhi, India.

Abstract: Vascular lesions of the orbit are important causes of visual decline and cosmetic blemish in children. Accurate
diagnosis and prompt management are essential to prevent these complications. This article provides a brief review of infantile
hemangioma and veno-lymphatic malformations of the orbit in children.

Vascular lesions are important imaging of choice as it delineates the Figure 1: 6-month-old child with orbital
causes of proptosis, visual loss and lesion and shows a markedly enhancing capillary hemangioma before, and three
ocular motility disorders in children. irregular lobulated mass. months after starting oral propranolol
Mulliken and Glowacki simplified Systemic examination is important therapy.
their nomenclature and classified them in these children as they may have hemangioma and cardiology clearance,
into vascular tumours and vascular hemangiomas elsewhere in the body, oral propranolol may be started at a
malformations. The most common some of which may be life-threatening. dose of 0.5 mg/kg daily and gradually
orbital vascular lesions in the pediatric Also, they can have other anomalies,
population are infantile hemangioma occuring as part of the PHACES
and venous lymphatic malformation. syndrome.Mostofthetimestheselesions
involute spontaneously and require
Infantile hemangioma only observation3. However, treatment
Infantile hemangioma is the most is advocated when visual functions are
common vascular tumour in children1. compromised. Prescription of glasses
These benign endothelial cell for refractive errors, and occlusion
neoplasms usually presents shortly therapy for anisometropic amblyopia
after birth in one-third of the patients, should be started as early as possible.
rapidly enlarges (proliferative phase) Oral, intralesional and topical steroids
for 3-6 months, and then involutes have been the standard medical
spontaneously, completely resolving by treatment for ages. However, long-
5-7 years of age2. The tissues involved term use of corticosteroids has its own
may be superficial (periocular) or deep disadvantages.
(orbital) or a combination of both. Recently, oral propranolol has gained
Loss of visual function in superficial popularity as first-line treatment for
lesions is often due to anisometropic infantile hemangioma (Figure 1).
amblyopia (when the lesion indents Approved by the FDA in 20144, it has
the globe or cornea) or stimulus good efficacy (99% cases respond to
deprivation amblyopia (a large lesion treatment)5 and safety profile. After
on the lid causing mechanical ptosis). baseline investigations like blood
Orbital lesions may cause optic nerve tests, electrocardiogram, abdominal
compression, or exposure keratopathy ultrasound to rule out visceral
due to severe proptosis. Magnetic
Resonance Imaging (MRI) is the

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 47

Subspeciality-Pediatric Ophthalmology (B)
(A)

Figure 2: 9-year-old child with veno-lymphatic malformation of the orbit before (A), and after (B) aspiration and single intra-lesional
bleomycin injection.

increased to 1-3mg/kg/day given in dioxide lasers have been attempted for visual decline needs medical or surgical
two divided doses6. Children started superficial skin lesions with varying intervention.
earlier on oral propranolol showed effects. Surgical excision is difficult
better treatment response than those and is reserved for lesions refractory to Systemic steroids are useful since they
who started late7. The treatment should other modalities of treatment. inhibit lymphoid hypertrophy and
continue till the end of the proliferative decrease the size of the lesion. Sclerosing
phase, usually till 8-12 months of age, Venous lymphatic malformation agents like bleomycin, Picibanil,
to avoid relapse. In children whose Previously called lymphangioma, these doxycycline, sodium tetradecyl
treatment started late, treatment can are congenital vascular malformations sulphate, ethanol and pingyangmycin
continue till maximum improvement and may demonstrate both lymphatic cause significant regression of the
is obtained. The dose is gradually and venous differentiation. Lesions lesions8. They are injected into the cystic
tapered over two weeks before are usually noticed in childhood with spaces after aspiration of cystic fluid.
stopping the drug. Minor side effects increasing proptosis and restricted The resultant aseptic inflammation and
observed include vomiting, diarrhoea, ocular motility, during an upper scarring causes vascular obliteration,
sleep disturbances, acrocyanosis and respiratory tract infection or due to with more favourable response seen
restlessness. Major side effects, though sudden bleed into the lesion. Visual in the macrocystic type of lymphatic
rare, are bronchospasm, bradycardia, loss may occur due to exposure malformation.
hypotension, hypoglycemia and keratopathy, optic nerve compression
hyperkalemia. Oral atenolol, or anisometropic amblyopia. They Bleomycin is commonly used for
metoprolol and acebutolol have also maybe of the microcystic (cyst size < the management of lymphatic
been tried for infantile hemangiomas. 1cm) or macrocystic (cyst size > 1 cm) malformations (Figure 2). The usual
Though not FDA approved, topical type. MRI shows a non-enhancing dose for injection is 0.5 IU/kg body
beta-blocker in the form of 0.5% ill-defined, infiltrative, multi- weight (1 IU/ml not exceeding 5 ml at
timolol maleate ophthalmic solution compartmental, multi-lobulated lesion a time) with the maximum allowed
applied twice daily is useful for with internal septations and fluid-fluid cumulative dose (including repeat
superficial lesions. Skin irritation and levels in lymphatic malformations. injections) being 5 IU/kg body weight.
sleep disturbances have been reported When venous component is present, Deep intraconal lesions are injected
as side effects. Intralesional propranolol there may be varying levels of contrast under ultrasonographic guidance.
(1 mg/ml) has also been tried and found enhancement. Superficial lesions are injected by
to give results comparable to oral Asymptomatic, cosmetically acceptable multiple puncture method under direct
propranolol. It may also be combined lesions may be kept under observation. visualisation9. Oral analgesics and ice
with intralesional steroids for small and Appropriate correction of refractive packs for local application are given
localised superficial hemangioma. error and amblyopia should be done. post-operatively. Pulmonary toxicity
Pulsed dye laser, Nd-YAG and carbon Larger lesions with severe proptosis or is a rare systemic side effect specific to
bleomycin. However, it is encountered
with much higher doses than the ones

48 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times

Subspeciality-Pediatric Ophthalmology

required for orbital lesions. Intralesional surgery and sclerosants were found to 9. Raichura ND, Alam MS, Noronha VO,
Pingyangmycin was found to be as be comparable, the latter is preferred Mukherjee B. A prospective study of
effective as bleomycin, while having as the first-line of therapy for orbital the role of intralesional bleomycin
fewer complications and being more lymphatic malformation. in orbital lymphangioma. Journal of
cost-effective10. Picibanil, obtained American Association for Pediatric
from Streptococcus pyogenes caused References Ophthalmology and Strabismus. 2017
regression of lesion in 96% patients11. Apr;21(2):146–51.
Risk of hemorrhage, reactive 1. Günalp I, Gündüz K. Vascular
inflammation and infection post- tumors of the orbit. Doc Ophthalmol. 10. Lam SC, Yuen HKL. Medical and
sclerosant injection should be explained 1995;89(4):337–45. sclerosing agents in the treatment
to the parents. Increase in the orbital of orbital lymphatic malformations:
compartment pressure due to injection 2. Bilaniuk LT. Vascular Lesions of the what’s new? Current Opinion in
of excess agent can cause optic nerve Orbit in Children. Neuroimaging Clinics Ophthalmology. 2019 Sep;30(5):380–5.
compression and permanent visual of North America. 2005 Feb;15(1):107–
loss12. 20. 11. Giguère CM, Bauman NM, Sato Y,
Bevacizumab, a recombinant Burke DK, Greinwald JH, Pransky S, et
humanized monoclonal antibody 3. Al-Haddad C, El Salloukh NA, El al. Treatment of Lymphangiomas With
against VEGF-A has also been tried Moussawi Z. blockers in the treatment OK-432 (Picibanil) Sclerotherapy: A
intralesionally in a few studies in of periocular infantile hemangioma. Prospective Multi-institutional Trial.
combination with bleomycin, and the Current Opinion in Ophthalmology. Arch Otolaryngol Head Neck Surg. 2002
outcome was favourable13. 2019 Sep;30(5):319–25. Oct 1;128(10):1137.
Low-dose oral Sildenafil in divided
doses, starting with 1 mg/kg/day and 4. Mehta A, Bajaj MS, Pushker N, Chawla 12. Patel SR, Rosenberg JB, Barmettler A.
gradual increase to 3 mg/kg/day have B, Pujari A, Grewal SS, et al. To compare Interventions for orbital lymphangioma.
been found to be a safe and effective intralesional and oral propranolol for Cochrane Eyes and Vision Group, editor.
method to reduce the volume of orbital treating periorbital and eyelid capillary Cochrane Database of Systematic
lymphangioma. Sirolimus given orally hemangiomas. Indian Journal of Reviews [Internet]. 2019 May 15 [cited
at a dose of 0.8 mg/m2 per dose and Ophthalmology. 2019 Dec 1;67(12):1974. 2020 Jul 30]; Available from: http://.
topically as 0.1% gel twice daily have
been used successfully in superficial 5. Spiteri Cornish K, Reddy AR. The use 13. Abdelaziz O, Hassan F, Elessawy K,
lymphatic lesions. Side effects include of propranolol in the management of Emad-Eldin S, Essawy RE. Image-
anaemia, hypertrigly ceridemia and periocular capillary haemangioma-a Guided Percutaneous Bleomycin and
secondary infections. systematic review. Eye (Lond). 2011 Bevacizumab Sclerotherapy of Orbital
Surgical excision, the traditional Oct;25(10):1277–83. Lymphatic Malformations in Children.
mode of treatment is often incomplete Cardiovasc Intervent Radiol. 2019
owing to the infiltrative nature of the 6. Hutchinson AK, Kraker RT, Pineles SL, Mar;42(3):433–40.
lesion, and recurrences are common. VanderVeen DK, Wilson LB, Galvin
It can be combined with intralesional JA, et al. The Use of -Blockers for the Corresponding Author:
sclerotherapy or fibrin glue, which helps Treatment of Periocular Hemangiomas
in easy mobilisation and excision of the in Infants. Ophthalmology. 2019 Dr. Mandeep S. Bajaj
mass. Since the treatment outcomes of Jan;126(1):146–55. Oculoplasty, Orbital Diseases, Lacrimal
Disorders and Ocular Tumors Services, Dr.
7. Al Dhaybi R, Superstein R, Milet A, Rajendra Prasad Centre for Ophthalmic
Powell J, Dubois J, McCuaig C, et al. Sciences. AIIMS, New Delhi, India.
Treatment of Periocular Infantile
Hemangiomas with Propranolol: Case
Series of 18 Children. Ophthalmology.
2011 Jun;118(6):1184–8.

8. Gandhi NG, Lin LK, O’Hara M. Sildenafil
for Pediatric Orbital Lymphangioma.
JAMA Ophthalmol. 2013 Sep
1;131(9):1228.

www.dosonline.org/dos-times DOS Times - Volume 26, Number 1, July-August 2020 49

Subspeciality-Pediatric Ophthalmology

“When all else fails” - Secondary
Episcleral Plaque Brachytherapy in
Retinoblastoma

Harika Regani, Santosh Honavar
Centre for Sight, Banjara Hills, Hyderabad, India

Retinoblastoma is the most common thickness, <16mm base. it with Co60. Subsequently, various
primary malignant intraocular tumor 3. Residual/recurrent irrespective of radioisotopes were used in the
in children. Trends in the management treatment of retinoblastoma, and the
of retinoblastoma currently focus location, >3mm thickness which advantages and the disadvantages of
on eye and vision salvage. Mortality are not amenable to other focal which are discussed in Table 15. Modern
rate is reduced to 2-5% with earlier treatments. plaques currently include assemblies
detection and improved treatment. 4. Vitreous seeding confined to <2mm of gold shells with low energy photon
The management is individualized, of tumor surface. s(Reeud1s06(Io12r5, SPr9d010)3,plCasq1u31e)s.oCr osmolpidarabtievtae
considering the age, laterality, number, dosimetry revealed that the lower
size, location and associated vitreous Contraindications weneerregmy oprheortaopnisdlfyroambsoPrdb1e0d3 irradiation
seeds. Intraarterial or intravenous 1. Anterior segment involvement. within the
chemotherapy along with appropriate 2. Diffuse vitreous seeds. target volume with less irradiation to
focal therapy is the current standard normal ocular structures.
of care. Although retinoblastoma is Methods of tumor localization
highly radiosensitive, external beam 1. Direct view using an indirect The radiation dose to the tumor apex
radiotherapy is not currently used for is important in terms of regression
primary or secondary management of ophthalmoscope. and has been evolving over the years
intraocular retinoblastoma because of 2. Posterior point source illumination after noticing poor response and
several complications associated with it, recurrences due to suboptimal doses
including second malignant neoplasm1. - Fiber optic or He-Ne light sources to the tumor apex6. Currently, a dose of
In patients with tumors refractory to or scleral depression combined approximately 4500-5000 cGy is usually
chemotherapy, residual tumors and with indirect ophthalmoscopy. followed.
recurrences, plaque brachytherapy has 3. Intraoperative ultrasonography.
emerged as a reasonable management 4. Morphometric (Ultrasonography Plaque design
option. combined with fundus photo). The radioisotopes are loaded on an
5. Plaque simulator software-guided. applicator (gold or silver). Ru106 is
Episcleral brachytherapy involves commonly used by the ophthalmic
placement of the radiation source in the Types of plaques surgeons in India due to its ergonomic
form of a plaque adjacent to the tumor, The various plaques used in the design. It is extremely easy to handle
and the radiation is delivered through treatment of retinoblastoma can be with a thickness of only 1mm. The
the sclera, thus reducing the damage to broadly classified as: radioactive core of the Ru106 eye
the surrounding ocular structures2. It applicator consists of a foil coated
has been used both as a primary and a 1. Photon emitters: I125, Pd103, Cs131 with Ru106 (0.2mm). This core is safely
secondary treatment modality. 2. Beta emitters: Ru106, Sr90 encapsulated within pure silver sheets
HB Stallard pioneered in the first (A silver window of 0.1mm and a silver
Indications3,4 with <8mm interstitial procedure for treatment backing of 0.7mm). The silver backing
1. Unilateral cases. of retinoblastoma in 1929, and later absorbs almost 95% of the beta radiation
2. Unifocal tumors developed the first radioactive plaque and acts as an effective radiation shield7.
applicator. He used Radium in his
first ten patients but later replaced

50 DOS Times - Volume 26, Number 1, July-August 2020 www.dosonline.org/dos-times