March-April'19 DOS Times

Editor-in-chief Subhash C. Dadeya, Editor-in-chief Radhika Tandon Volume 24 No. 5, March - April, 2019
Subhash C. Dadeya Editor

Patrons Savleen Kaur Shibal Bhartiya
A.K. Gupta G. Mukherjee Executive Editor Executive Editor
Gurbax Singh L.D. Sota
Madan Mohan M.S. Boparai, P.K. Khosla APasslliasvtai nDtoEkdaintoiar MAsosnisictaanLtoEhdcihtoabr ARsistiikstaaMntuEkdhiitjoar

Chief Advisory Board Editorial Recent Trends and Advances
Atul Kumar, Cyrus Shroff Harbansh Lal, Lalit Verma 5 Keeping upto date 64 Medicine Update for
Mahipal Sachdev Radhika Tandon Ophthalmologists
Rajendra Khanna, Rishi Mohan, Ritu Arora , Featuring Sections 70 Astigmatism and Cataract
R.V. Azad, S. Bharti, Sudarshan Khokhar, Surgery: Current Concepts
Sushil Kumar Y.R. Sharma
Expert Corner Case Reports
Editors 7 Refractive Surgery 73 An Unusual Case of Bilateral
Radhika Tandon Savleen Kaur, Shibal Bhartiya
Review Articles Cataract with Anabolic Steroids
Assistant Editors 38 Zepto-Assisted Cataract Surgery: 75 Ocular Surface Squamous
Monica Lohchab Pallavi Dokania An Interesting Technology Neoplasia with Superficial
Ritika Mukhija 41 Cataract Surgery in Operated Fungal Colonization
Trabeculectomy Patients: Pearls 76 A Case of Pressure Induced
International Advisory Board and Pitfalls Stromal Keratitis
Arvind Chandna Derek Sprunger, Frank Martin
J. Panarelli, Larson Scott Saurabh Jain, Seyhan Obzkon 45 IOL Power Calculation Formulas: News Watch
Sonal Ferzavandi Surabhi Shalini A Major Review 78 DOS Times Quiz
50 Cataract Surgery-Evolution 80 DOS Crossword
National Advisory Board through Ages 81 Author Guidelines
A.K. Khurana, B.N. Gupta B.S. Goel, Barun Nayak
Chaitra Jaidev, Chand Singh Dhull Deepak Mishra, D. Ramamurthy Perspectives Tear Sheet
Dharmender Nath Gursatinder Singh 54 Keeping the Hope Alive - Building 83 IOLs for Presbyopia
Hemalini Samant, Jagat Ram Jai Kelkar, Kamaljeet Singh
Krishna Prasad Kundlu Manisha Rathi, Mangat Dogra A Tertiary Eye Centre
R.K. Bansal, Ragini Parekh Rakesh Porwal
S.P. Singh, Sandeep Saxena Sanjeev Nainiwal 57 Capsulotomy for Cataract
Sudesh Arya, Santhan Gopal Santosh Honavar
Shreya Shah, Sudhir Kumar Swapan Samantha, T.S. Surendran Surgery- Evolution of A Journey
V. Saharanamam Vandana Jain, Vinita Singh
Virendra Agarwal Yogesh Shukla 61 Refractive Surgery for

Delhi Advisory Board Occupational Reasons: The
A.K. Grover, Abhinandan Jain Ajay Aurora, Ajay Sharma
Alkesh Chaudhary Amit Chopra, Amit Khosla Ophthalmologist’s Role
Anju Rastogi Anuj Mehta, Anup Goswami
Arun Baweja, Arun Sangal Ashwini Ghai, Ashu Agarwal,
B.P. Guliani, Bhavna Chawla Dinesh Talwar
D.K. Mehta, G.K. Das H. Gandhi, H.S. Sethi, H.S. Trehan
J.K.S. Parihar, J.S. Titiyal Jatinder Bali, J.L. Goyal
J olly Rohatgi, Kamlesh, K.P.S. Malik K.R. Kuldeep, Kamal Kapoor
K irti Singh, Lopa Sarkar, M. Vanathi M.C. Agarwal, M.L. Bharti
Mahesh Chandra Manisha Agarwal
Meenakshi Thakkar Mohita Sharma
Mukesh Sharma N.Z. Farooqui, Nabin Pattnaik
Namrata Sharma, Neeraj Sanduja, Noshir Shroff
Om Prakash O.P. Anand
P.K. Pandey, P.K. Sahu, P.N. Seth Pawan Goyal, Piyush Kapur
Poonam Jain, Pradeep Sharma Praveen Malik, Punita K. Sodhi
Rajendra Prasad, Rajesh Sinha Rajiv Bajaj, Rajiv Garg,
Rajiv Mohan, Rajiv Sudan Rajpal, Rakesh Bhardwaj
R.B. Jain, Ramanjit Sihota Rakesh Mahajan, Rohit Saxena
Sagarika Patyal Sandhya Makhija
Sanjay Chaudhary Sangeeta Abrol, Sarita Beri
Sarika Jindal, Satish Mehta Shashi Vashisht
Sunil Chakravarty, S.N. Jha Suma Ganesh, S.M. Betharia
Sushil Kumar, Tanuj Dada Taru Dewan, Tushar Agarwal
Tinku Bali, Umang Mathur Usha K. Raina, V.K. Dada
V.P. Gupta, V. Rajsekhar V.S. Gupta, Vinay Garodia
Viney Gupta, Vipul Nayar Yogesh Gupta

Section Editors
Strabismus & Oculoplasty
Paediatric Hardeep Singh
Ophthalmology Mridula Mehta
Abhishek Sharma Rachna Meel
Annu Joon, Anirudh Singh Seema Das
Deepali Mathur Sumita Sethi

Geetha Srinivasan Neuro-ophthalmology
Rasheena Bansal Promita Dutta, Satya Karna
Renu Grover, Sumit Monga Swati Phuljhele, V. Krishna

Glaucoma Retina
Deven Tuli, J.S. Bhalla Bhumika Sharma
Mainak Bhattacharya Bhuvan Chanana
Manavdeep Singh Darius Shroff
Reena Chaudhary Deependra Vikram Singh

Cataract & Refractive Devesh Kumawat
Abhishek Dagar Koushik Tripathy
Charu Khurana Naginder Vashisht
Reena Sethi Raghav Ravani
Ritika Sachdev R.P. Singh, Ritesh Narula
Sanjiv Mohan Vinod Kumar Agarwal

DOS Correspondents Cornea & Oular Surface
Divya Kishore Manisha Acharya
Manisha Mishra Noopur Gupta
Mohit Chhabara Parul Jain, Pranita Sahay
Prateeksha Sharma Rajat Jain
Richa Agarwal, Shweta Dhiman Uma Sridhar
Sumit Grover, Yashpal Goel Vikas Veerwal

DOS TIMES
Editorial Assistance & Layout: Sunil Kumar

Cover Design: Aman Dua
DOS Times will hitherto be published once every two months by Dr. Subhash C.
Dadeya, on behalf of Delhi Ophthalmological Society, DOS Secretariat, Guru Nanak
Eye Centre, New Delhi. Printed by Pushpak Press Pvt. Ltd. (Registration No. F-1P-1
Press CCS, 2011). All solicited & unsolicited manuscripts submitted to Dos Times
are subject to editorial review before acceptance. DOS Times is not responsible for
the statements made by the contributors. All advertising material is expected to
conform to ethical standards and acceptance does not imply endorsement by DOS
Times. ISSN 0972-0723.

www. dos-times.org 3

DOS EXECUTIVE MEMBERS

Executive Committee: DOS 2017-2019

DOS Office Bearers

Dr. Sudarshan Kumar Khokhar Dr. Subhash C. Dadeya
President Secretary

Dr. Rakesh Mahajan Dr. Arun Baweja Dr. Manav Deep Singh Dr. Bhavna Chawla Dr. Jatinder Singh Bhalla
Vice President Treasurer Joint Secretary Editor Library Officer

Executive Members DOS Representative to AIOS

Dr. Radhika Tandon Dr. Hardeep Singh Dr. Alkesh Chaudhary Dr. Naginder Vashisht Dr. Rohit Saxena

Dr. Vinod Kumar Dr. Sandhya Makhija Dr. Pawan Goyal Dr. M.C. Agarwal Dr. Ashu Agarwal

Ex-Officio Members

Prof. Kamlesh Dr. M. Vanathi Dr. Vipul Nayar
Ex-President Ex-Secretary Ex-Treasurer

DOS Hall of Fame Satish Sabharwal J.C. Das Dos General Secretaries
DOS Presidents N.C. Singhal Gurbax Singh
Madan Mohan Noshir M. Shroff Hari Mohan R.V. Azad
S.N. Mitter A.C. Chadha Pratap Narain Mahipal S. Sachdev R.S. Garkal B. Ghosh
H.S. Trehan M.S. Boparai (Brig.) R.C. Sharma Lalit Verma S.R.K. Malik Mahipal Sachdev
Tej Pal Saini N.N. Sood B.N. Khanna S. Bharti Madan Mohan Atul Kumar
L.P. Agarwal P.K. Jain R.N. Sabharwal Sharad Lakhotia J.C. Bhutani Lalit Verma
D.C. Bhutani L.D. Sota N.L. Bajaj P.V. Chadha S.C. Sabharwal Dinesh Talwar
R.C. Aggarwal L.D. Sota Mathew M. Krishna B.P. Guliani A.C. Chadha Harsh Kumar
S.N. Kaul S.K. Angra Prem Prakash Harbansh Lal Pratap Narain J S. Titiyal
S.N. Kaul D.K. Mehta D.K. Sen J S. Titiyal S.K. Angra Harbansh Lal
H.S. Trehan Y. Dayal P.K. Khosla Rajendra Khanna G. Mukherjee Namrata Sharma
Hari Mohan K.P.S. Malik K. Lall Cyrus Shroff H.K. Tewari Amit Khosla
R.S. Garkal R.B. Jain A.K. Gupta Rishi Mohan R. Kalsi Rohit Saxena
J.C. Bhutani G. Mukherjee B. Pattnaik Kamlesh D.K. Mehta Rajesh Sinha
S.R.K. Malik R.V. Azad A.K. Grover P.C. Bhatia M. Vanathi
Tejpal Saini Satinder Sabharwal K.P.S. Malik Subhash Dadeya
Arun Sangal

Sincere thanks to all DOS Office Staff : Office Secretary: Parveen Kumar w DOS Accountant: Sandeep Kumar w DOS Times Assistant: Sunil Kumar
Library Attendant: Niyaj Ahmad w Office Attendant: Harshpal

5 DOS Times - March-April 2019

Editorial

Keeping upto date

Dear colleagues and friends!!

Major changes in cataract and refractive surgery today requires Dr. (Prof.) Subhash C. Dadeya
ophthalmologists to continuously keep updated in new diagnostic modalities
and new treatment methods. Cataract surgery has been the gold standard
for decades now and yet it is the subspeciality that has seen the maximum
evolution. From couching to operating under the microscope, we have evolved
to the premium intraocular lenses. The revolution in this area is so exploratory
that before we master one technique, another is at our doorstep leaving us
awed. Refractive surgery is one of the fastest evolving specialties in Ophthalmology

with a sharp rise in the number of cases seen over the past one decade. A plethora

of options is now available to both the surgeon and the patient, thereby making a
wide variety of patients suitable for refractive correction. This new issue of the
DOS times will give us an opportunity to discuss latest hot topics with our
friends and colleagues. We have put together an exciting issue with focus on
refractive surgeries and viral topics like IOL power calculation in children. We
also present an article on medicine for ophthalmologists which we have all
read somewhere but need to remember always.

We are also pleased to announce that the annual conference was a huge success with a whole-hearted participation
from ophthalmologists nationwide. The previous issues were well received, and I would like to thank the readers,
contributors and the DOS times team for believing in the journal.

Thanks

Dr. (Prof.) Subhash C. Dadeya
Secretary - Delhi Ophthalmological Society
Room No 114, 1st Floor, OPD Block,
Guru Nanak Eye Centre, Maharaja Ranjit Singh Marg,
New Delhi - 110002
Email: [email protected], [email protected]
Mobile: 9968604336, 9810575899
WhatsApp: 8448871622

www. dos-times.org 7

Expert Corner

Refractive Surgery

Prof. (Dr.) Sudarshan Kumar Khokhar Prof. (Dr.) Jagat Ram Prof. (Dr.) Mahipal S. Sachdev

Prof. (Dr.) Radhika Tandon Dr. O.P. Anand

Refractive surgery is one of the fastest evolving specialties in Ophthalmology with a sharp rise in the number of cases seen over

the past one decade. A plethora of options is now available to both the surgeon and the patient, thereby making a wide variety of

patients suitable for refractive correction.

We therefore asked a panel of renowned refractive surgeons from all over the country to discuss about their views on the

various aspects of management in these cases and to shine light on certain grey areas in refractive surgery. The questions have
been prepared by Dr. Ritika Mukhija (RM) Senior Resident Cornea, Cataract & Refractive Surgery Services, from R.P. Centre for
Ophthalmic Sciences, All India Institute for Medical Sciences, Ansari Nagar, New Delhi, India

(SK) Prof. (Dr.) Sudarshan Kumar Khokhar: He is currently working as Professor of Ophthalmology at Rajendra Prasad Centre
Ophthalmic Sciences, All India Institute of Medical Sciences New Delhi, India.

(JR) Prof. (Dr.) Jagat Ram: He is currently working as Professor at Advanced Eye Centre and Director, PGIMER, Chandigarh,
India.

(MS): Prof. (Dr.) Mahipal S. Sachdev: He is Chairman, Medical Director & Senior Consultant Ophthalmology at Centre For Sight
Group of Hospitals.

(RT) Prof. (Dr.) Radhika Tandon: She is currently working as Professor of Ophthalmology at Dr Rajendra Prasad Centre for
Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi.

(OPA) Dr. O.P. Anand: He is currently working as Chief Eye Surgeon at Northern Railway Division Hospital, S.P. Mukherjee Marg,
Delhi, India.

www. dos-times.org 9

Expert Corner at any place which offers good fellowship under
experienced surgeon.
RM: Since when have you been performing Refractive JR: I learnt the procedure during my short stint in
Surgery? How many years so far? the USA. I feel PGI, Chandigarh now has the latest
expertise, infrastructure and technology to train
SK: More than15 years. anyone who wants to acquire that skill. Additionally,
JR: I have been performing refractive surgery for the a skills transfer course could be helpful for surgeons
wanting to learn the new technical skills and
past 10 years. nuances of corneal refractive surgery.
MS: I have been performing Refractive Surgery for MS: I received my postgraduate training at the Dr.
RP Centre for Ophthalmic Sciences, AIIMS and
over three decades now. Refractive surgery has subsequently went on to pursue my fellowship at
witnessed various advancements including Georgetown University, Washington DC.
the advent of femtosecond laser, Small Incision RT: I learnt the procedure at the Dr Rajendra Prasad
Lenticule Extraction and posterior chamber phakic Centre for Ophthalmic Sciences, AIIMS. The best
intraocular lenses, making it a rapidly developing places or platforms would be centres with state of
field. the art facilities, well trained surgeons with good
RT: Nearly 2 decades. 20 years. track record and adequate experience who are
OPA: Since 6 years I am performing refractive surgery. committed and passionate about teaching.
OPA: Best place or platform to learn right technique;
RM: What motivated you to take up this field? you should overcome your limitations and machine
What was the prime driving force behind your limitations, which is safest & best technique in
decision to start practising Refractive Surgery? your hand. Any institution with long followup of
refractive patient.
SK: According to reports in journals, there is increased
incidence of myopia due to lifestyle changes, RM: What differences have you noticed in the patient
increased expectancy, obesity, diabetes, ROP etc demographics seen in India compared to other
and need for refractive surgeons has increased 200 countries?
folds. That was quite motivating.
SK: Ocular parameters are different in our population.
JR: My motivation for pursuing refractive surgery as We have mean lower corneal thickness, White to
a subspecialty was primarily fuelled by patient’s white and anterior chamber depths.
enthusiasm and a relatively high overall degree of
patient satisfaction. Corneal refractive surgery is JR: No Answer.
proven to deliver high quality uncorrected vision, MS: The patients presenting for refractive surgery
with a very low side effect profile.
comprise a younger age group as compared to the
MS: I was interested in Cornea as a speciality since my western population. A significant proportion of
postgraduate days, and pursued a fellowship for the demography presenting for correction include
the same at Georgetown University, Washington. female patients in search of matrimonial aspects.
I am additionally passionate about acquiring the RT: In our scenario the majority of patients are in
latest technology to deliver best patient outcomes. 20-30 age group, predominantly wanting to get
Refractive surgery combines my two passions and rid of spectacle dependence for improving their
was thereby a clear choice for me. quality of life including resolving issues pertaining
to marriage or hobbies such as active sports for
RT: Motivation was to provide an unmet patient example swimming and mountaineering. A sizeable
need. The prime driving force was to bring this proportion is seeking surgery for professional
technological advance within reach of our patients. reasons for recruitment to the armed forces,
I started practising refractive surgery as I perceived police, railways and professional sports. So far,
an opportunity to provide a life changing sight the number of patients approaching for refractive
restoration procedure to those who could benefit. surgical correction is less in middle age 40-50, but I
Also, it is important to be able to train surgeons expect that will change as the results of presbyopia
to provide the service in a safe and dependable corrective procedures improve and become more
manner. As a surgeon and teacher, I take it as a part widely accepted. Cataract surgery is now viewed
of my responsibility to acquire the requisite skills as a refractive surgical procedure and patients
and impart the knowledge. It is very rewarding to with cataract form a different segment. We see
have excellent results in terms of patient outcomes very few patients seeking options for spectacle
and trainee performance. independence (apart from removal of cataract) in
the older ages, while it is fairly common to have
OPA: Main motivation is to achieve perfect vision for the refractive surgical procedures undertaken for the
patient , without any glasses or contact lenses. elderly in other countries.
OPA: Every patient has different biological behaviour
RM: Where did you learn the procedure? What would and can behave differently or adversely to the same
you suggest as the best places or platforms to
learn for those who want to acquire this skill?

SK: I learnt it at my alma mater; Dr R P centre for
Ophthalmic Sciences, AIIMS where we have
exposure to latest technology. You can learn it

10 DOS Times - March-April 2019

Expert Corner

treatment protocol for a similar eye disease. complications.
RT: I do believe that it is a highly specialized procedure
RM: Nowadays, cataract surgery is also included as
a form of Refractive surgery. Do you agree with and the full package includes a proper understanding
that? Please explain your point of view? of the optics, the options, the correct interpretation
of investigations, the pre-screening for risk factors
SK: Refractive lens exchange is a part of refractive that could lead to serious complications, the
surgery. Early cataract surgery can be considered in discussion about limitations and proper choice of
patients >40years with demand to get rid of glasses procedure, the ability to pre-empt and promptly
especially high myopia. Multifocal IOLs also can take care of potential and real complications and
reduce spectacle dependence. have the experience to properly interpret the
investigations and titrate the treatment and post op
JR: Yes, I absolutely agree with that. With the increasing management according to the needs.
popularity of refractive cataract surgery, patient OPA: I will say any ophthalmologist. I think it’s a surgeon
expectations run high. Sometimes even with good decision to choose method which is best suited in
surgical planning and newly available technologies, their hand.
patients don’t end up on refractive target, so laser
vision correction is a handy tool in such scenarios. RM: What are the major advances in Refractive
surgery practice that have revolutionised the
MS: Laser Refractive Cataract Surgery allows precision field?
in surgical outcomes to achieve the result of
emmetropia. The construct of a precise capsulotomy SK: Investigative modalities such as scheimpflug
allows an optimal effective lens position. imaging has made a difference in corneal topography
Additionally the construct of arcuate keratotomies and tomography assessment. Aberrometers to
allows treatment of low corneal astigmatism. check HOAs have also helped a great deal.
With the advent of premium intraocular lenses JR: Surgically, laser machines including excimer and
including toric and multifocal implants, optimal MS: femtosecond lasers have revolutionised refractive
visual outcomes without glasses are now possible surgery. We have faster laser machines with better
following cataract extraction. eye tracking. SMILE is also showing promising
results.
RT: I certainly do. It is indeed important to treat every In ICLs, because of V4c model now, PI is not
case as such and make every effort to fine tune needed. They are kept in BSS instead of saline and
all steps to provide the possibility of spectacle vaulting does not change much after immediate
independence. Practically, there may sometimes be postoperative period. Intraoperative aberrometry
limitation in truly reaching this goal, but it is good such as ORA, has a potential to improve IOL power
to have a discussion with the patient and relatives calculation especially post refractive surgery eyes
about the options and understand their visual and rotation of toric IOLs. CALLISTO and Verion can
needs and communicate the best case scenario. also be used for Toric IOL planning and eliminating
the need for manual marking.
OPA: Yes, why not, Corneal astigmatism and other In the past, refractive surgery was limited to
existing refractive errors including presbiopia can procedures like LASIK and PRK, but now it
be managed during cataract surgery with available encompasses additional procedures like small
advance lenses. incision lenticule extraction (SMILE, Carl Zeiss
Meditec, Jena, Germany), crosslinking, and phakic
RM: Do you feel Refractive Surgery should be IOL implantation and Femtosecond Laser Assisted
done only by persons with a comprehensive Cataract Surgery.
Refractive surgery practice? Please explain your The advent of Small Incision Lenticule Extraction
point of view? allows refractive correction using a flapless
bladeless technique. It is one of the major advances
SK: Absolutely. Contrary to the common belief, that we have witnessed in the past decade with
refractive surgery is a specialized branch where superior biomechanics, lower incidence of
we are treating healthy individuals with refractive postoperative dry eye and greater preservation of
error. Tolerance of inadvertent complications is very corneal asphericity vis-à-vis its predecessors.
low. Hence, complete understanding of principles There is a whole host of amazing inventions and
and procedure of refractive surgery is necessary. innovations and one is emboldened to proceed on
the strength of the wealth of armamentarium and
JR: No, I feel it should be done even by comprehensive plethora of knowledge available to us today. I would
ophthalmologists. Cataract surgeons should also acknowledge the first idea that a surgical procedure
have a skill set and option to help correct surprises could be offered to optically correct a refractive
from refractive errors after cataract surgery. error was the first step. The procedure became
more acceptable to me personally (as I was not truly
MS: I strongly believe Refractive Surgery should be enamoured by RK) with the invention of the Excimer
practiced by ophthalmologists trained in the
speciality. Ideal treatment entails not only a well
executed surgical procedure, but a thorough
understanding of preoperative patient screening
and competent management of associated

www. dos-times.org 11

Expert Corner technically easier to perform.
MS: Not at all. On the contrary I believe the field is fast
Laser which is of course a major improvement,
supported by the Femtosecond Laser for precise evolving. Advancements in technology and greater
blade free creation of a flap. Better realization of the understanding of the corneal biomechanics will
importance of residual bed thickness, limitations of allow safer and superior visual outcomes in the
corneal refractive procedures beyond safe limits, future.
programmes with flying spot lasers, tissue sparing RT: Of course, there are still limitations in recovery;
protocols, real time in vivo tracking and aspheric there is scope for better technologies. There are
ablation are other significant developments. I must borderline scenarios where one is unsure of the best
mention the tremendous benefit of having access option to choose. Complications are a big bug bear
to better modern instrumentation particularly particularly the dreaded ones of infection, scarring,
Scheimpflug Tomography for better imaging of the post LASIK ectasia, and retinal detachment. Despite
cornea to screen out patients with Forme Fruste best efforts and all precautions, one is still limited
Keratoconus, or those at risk for post LASIK ectasia. by biological factors and individual variations which
ICL expanded the range of patients whom we could can still lead to undesired side effects to a greater or
help and again, personally I did not personally lesser degree such as trouble with halos, glare, night
use the iris supported lenses or the older models driving problems, persisting dry eye, regression etc.
requiring iridotomy and was comfortable with Undoubtedly, with far better understanding of the
offering phakic IOL in the range of services only etiopathogenesis of these problems, we have moved
after the newer designs with soft collamer material far ahead from the past and the unhappy patient is
and the aquaport for aqueous drainage became rare but never to be ignored or forgotten.
available. I also feel the SMILE technique is great OPA: Shortcoming in the field :- to get rid of complication
and am happy with the results. Another wonderful which are widely due to machine/consumable/
advance is the concept of the Belin Ambrosio Error /Selection of Cases.
(Enhanced Ectasia) Display or BAD for further Intraoperative Complications:-Microkeratome-
screening out patients of keratoconus and the related flap complications;Flap Buttonhole;
benefit of using the calculation of percentage tissue Free Cap; Incomplete, short, or irregular flaps;
altered (Ablation depth plus flap thickness divided Corneal perforation; Vertical gas breakthrough;
by corneal thickness) and ensuring it is kept below Anterior chamber gas bubbles;Corneal Epithelial
40%. The list is in fact endless. Defect; Limbal Bleeding; Interface Debris;
OPA: Major advances in refractive Surgery major Postoperative Complications:- Overcorrection
innovations and breakthroughs have helped to and Undercorrection; Flap Fold or Striae;
make refractive surgery safe, precise, predictable Macrostriae;Microstriae; Flap Dislocation; Dry
and stable and improved not only the vision but Eye and Corneal Sensation;. Diffuse Lamellar
the quality of life of millions of patients who have Keratitis (DLK); Pressure-induced Stromal Keratitis
benefited from it. At the same time complications (PISK); Central Toxic Keratitis (CTK); Infectious
remind us to be extremely cautious and careful Kertatitis;Epithelial Ingrowth; Ectasia.
before we advise any refractive procedure and
to be meticulous and methodical at every step of RM: Do you have any experience with performing
examination, surgery and follow up. Refractive surgery in children?

RM: Do you have any concerns about any SK: Multifocal IOLs are used in paediatric cataract
shortcomings in the field? surgery in children > 5yrs of age.

SK: Despite taking all the precautions and checking No experience with corneal refractive surgery in
corneal parameters, there is always a chance of children as such.
ectasia post corneal refractive surgery. Factors
causing ectasia have not be completely understood. JR: We have successfully done FLACS in children with
Dry eye still remains a common complication, we subluxated lenses.
haven’t found a way to completely avoid it. There is
no perfect way of measuring corneal hysteresis. MS: Refractive surgery in children is rarely performed
as the refractive status has yet to gain stability. The
In ICL, we haven’t completely eliminated risk of only indication for refractive correction is high
cataract and glaucoma. They have to be removed anisometropia inducing amblyopia, wherein contact
eventually. lenses and glasses are not suitable treatment
modalities. It is imperative to counsel the parents
JR: Though there are no major shortcomings about the possibility of increase in refractive error
in refractive surgery procedures, our job as with advancing axial length, and the need for a
ophthalmologists is to discuss the risks, benefits, secondary intervention at a later date.
and alternatives of every refractive surgery option
with the patients. PRK and LASIK are two options RT: No.
for procedures that refractive surgeons use. When OPA: Corneal refractive surgeries - NO
it comes to choosing between PRK and LASIK, Lens based refrective surgeries can be considered
PRK has less of a chance for ectasia and it is also
in case of anisometropia cases to prevent amblyopia
12 DOS Times - March-April 2019 and diplopia.

RM: Do you have any personal views on the limited Expert Corner
recommendations of Refractive surgical
procedures for children reported worldwide? present, should be treated before performing any
cornea based refractive surgery.
SK: Only few studies have been conducted in children For ICL surgery, Endothelial anterior chamber
between 5-15 years for ICL implantation. It is depth should >2.8 mm in myopia and > 3mm in
useful especially in cases with anisometropia. Few hyperopia and specular count should be> 2300.
challenges are there. The rapid change in power of Corneal biomechanics is a non invasive tool for in-
glasses and lower anterior chamber depth cause vivo detection of structural properties of cornea
difficulty. Need for general anaesthesia is also a and can help in detecting keratoconus and better
concern. Corneal surgery in children has risks due planning of refractive surgery. Ocular response
corneal moulding and lack of long term follow-up in analyser has been in use for sometime now. Corvis
previous studies warrant caution. ST is the newer modality which generates Corvis
Biomechanical Index (CBI) that helps in detecting
JR: Most children with refractive errors can be treated early keratoconus.
successfully with glasses or even contact lenses. JR: Essential screening tools used by me include
Refractive surgery can be a reasonable option for corneal topography, corneal thickness, Percentage
children with anisometropic amblyopia, bilateral tissue ablation and residual stromal bed thickness.
high ametropia or refractive accommodative Percent tissue altered greater than 40% at the
esotropia that does not respond to standard time of LASIK is significantly associated with
conventional treatment and for improving quality the development of ectasia in eyes with normal
of life for children who have behavioural or preoperative topography.
developmental problems that make it difficult to Elevation data, especially from the posterior
wear glasses or contact lenses. 10 years of age is cornea, is key to increasing your odds of catching
often cited as the upper age limit for performing an abnormal cornea before you operate. In almost
refractive surgery on a child with anisometropic every keratoconus patient I have encountered,
amblyopia and PRK is the most commonly the changes on the posterior surface are more
performed refractive procedure in children due prominent and sometimes occur in the absence of
to its better safety profile and no flap related any changes on the anterior surface any changes on
complications. the anterior surface
In study by Randleman et al, more ectasia cases
MS: Again refractive surgery should be considered had abnormal preoperative topographies (35.7%
as a treatment modality only in cases to prevent vs. 0%; P<1.0×10−15), were significantly younger
amblyopia wherein contact lenses are not a feasible (34.4 vs. 40.0 years; P<1.0×10−7), were more
modality and full spectacle correction induces myopic (−8.53 vs. −5.09 diopters; P<1.0×10−7), had
significant aniseikonia. thinner corneas before surgery (521.0 vs. 546.5 μm;
P<1.0×10−7), and had less RSB thickness (256.3 vs.
RT: It is a grey area and must be taken with reference 317.3 μm; P<1.0×10−10).
to individual context and patient needs keeping in MS: The most important tool in the armamentarium
view the clinical scenario. of preoperative screening is corneal tomography.
Devices which truly measure the posterior corneal
OPA: Each individual ophthalmologist/Surgeon may surface are preferred over ones wherein the
have a preference for a particular procedure based posterior data is extrapolated. A healthy ocular
on economic reasons, availability factor, or his surface with a stable tear film is essential for ideal
own personal satisfaction with the end results of a outcomes and should be assessed preoperatively.
particular procedure. The role of corneal biomechanics in screening
for refractive surgery is evolving. However, at the
RM: What are the essential screening tools used by current stage of development various shortcomings
you for the screening of patients for refractive including lack of repeatability limit its true
surgery and what are the critical parameters potential. The advent of Brillouin microscopy
for the same? Do you feel corneal biomechanics with the ability to perform vivo biomechanical
has any role in screening patients for refractive assessment of the various corneal layers will be an
surgery? important landmark in the screening process.
RT: Careful history paying particular attention to
SK: Corneal topography is essential screening tool to evolution of the refractive error, family history,
minimize the risk of ectasia. Critical parameters past treatment records, contact lens usage, visual
vary according to the instrument eg posterior needs, patient’s motivation and expectations,
elevation cut off for suspicious and abnormal life style pattern and hobbies. A comprehensive
reading is >15 and >20u for Pentacam HR while the eye examination including cycloplegic refraction
same for Orbscan is >30 and >40u respectively. CCT and screening of retinal periphery by indirect
should be >470u, RSBT should be >250u ideally ophthalmoscopy. Pentacam with BAD in addition
(>300u), PTA <40%, Post Km between 34-49D and to the standard mapping. An orthoptic check up,
BAD should be normal. optical biometry, color vision(only those applying

Corneal surface needs to healthy. TBUT and www. dos-times.org 13
Schirmer’s test should be performed. Dry eye, if

Expert Corner changes are either greater on the posterior surface
or only present on the posterior surface so the
for army/polic/railways), glare and contrast posterior surface is a much more sensitive indicator
sensitivity, wavefront analysis and estimation than the anterior surface. One can plan for refractive
of corneal biomechanics (only when specifically surgery after proper screening.
indicated) are also done.
OPA: Three dimensional topography; slit scanning RM: What is your experience in cases with mild
(Orbscan); scheimpflug imaging (Pentacam); superficial paracentral corneal opacities
high speed anterior segment optical coherence with best corrected vision 6/6 and normal
tomography; pachymetry requesting refractive correction?
Corneal Biomechanics have equal role in screening What procedure would you prefer?
patients for refractive surgeries. It provides the
enhanced screening approach, so that we can SK: Superficial mild paracentral opacities generally
identify ectasia susceptibility, and this is what are insignificant and both LASIK and SMILE can
is relevant to refractive surgeons when they are be performed. Visual outcomes are good. We do an
assessing a patient’s suitability for surface ablation ASOCT in all patients with opacity to look at depth
or LASIK. of opacities. In slightly deeper and more dense
opacities FS-LASIK and SMILE should be avoided.
RM: When the keratometry and pachymetry are Microkeratome assisted LASIK or PRK can be
within normal range, but the BAD is abnormal considered.
with only front difference and a normal back
difference (on Pentacam), what would be your JR: We prefer PRK in such cases as we can encounter
approach in managing these cases? difficulties during flap lifting.

SK: Abnormality of the front map warrants treatment MS: The choice of procedure would depend on the depth
for the tear film when all the other parameters are and the position of the corneal opacity. The anterior
normal. In most cases of keratoconus, changes in segment OCT is a useful tool to detect the depth of
the back surface are more pronounced. Only front the opacity. Femtosecond assisted procedures like
difference generally suggests tear film abnormality LASIK and SMILE may be associated with the risk
hence, frequent lubrication, discontinuation of of a vertical gas breakthrough in deeper opacities
contact lens and MGD treatment is advisable. After and should be avoided. Surface ablation would
resolution, repeat pentacam needs to be performed. be my preferred option in these cases as it would
If the abnormality disappears, refractive surgery additionally allow to debulk the opaque tissue akin
can be considered. If not so, we should withhold to phototherapeutic keratectomy. For peripheral
surgery till problem resolution and watching out superficial opacities (less than 90 microns), deeper
for progression. flaps can be fashioned and one can proceed with
femtosecond LASIK or SMILE.
JR: Patients with front elevation are told to avoid
wearing contact lenses for a month to prevent RT: I counsel the patient and elect for surface ablation
corneal warpage and then repeat topography. (PRK).

MS: One should rule out contact lens warpage by OPA: Is it really necessary to go for refractive procedure??
obtaining history of contact lens usage. I prefer Any other visual discomfort experienced by patient
a discontinuation of soft and rigid contact lenses to be examined any viral pathology resulting
for a duration of one and three weeks prior to corneal opacity may be examined.
corneal tomography imaging respectively. The
corneal surface should be examined for any subtle RM: What is your experience with “Contoura LASIK”
corneal opacities. Front difference elevation is also and in which cases would you prefer this?
commonly associated with steep corneas and is not
a contraindication for refractive surgery. SK: We have been using contoura LASIK since
3-4 years. In our experience, there is minimal
RT: I recheck for any chance of contact lens warpage, difference between wavefront optimized LASIK and
look carefully for ocular surface disease and use topoguided LASIK. If RMS is more or more HOAs on
the iTrace to look for corneal aberrations, corneal anterior corneal surface, then contoura is useful.
biomechanics and epithelial mapping platforms to
look for abnormal corneas such as FFKC. I counsel Limitation is the inability of machine to capture
the patient and treat any identified modifiable risk satisfactory quality of images in all patients
factors. Investigations are repeated again after 3 preoperatively.
months and look for worsening. Monthly follow
up continues for a year and if values normalize, I JR: In addition to correcting the refractive error,
proceed with surgery. If refractive error remains Contoura Lasik also corrects the patient’s corneal
stable but cornea is still abnormal, I consider irregularities while working on the visual axis,
patient for ICL. thereby providing much sharper visual outcomes.
It has a special Topolyser which is able to map and
OPA: Belin/Ambrósio Enhanced Ectasia Display (BAD) remove corneal irregularities by marking 22,000
software can detect early keratoconus with a unique elevation points on the cornea. I would
sensitivity and specificity of 98%. As we know prefer it for topography guided LASIK treatments

14 DOS Times - March-April 2019

for the reduction or elimination of up to –8.00 D of Expert Corner
myopia and up to 3.00 D of astigmatism.
MS: Contoura LASIK allows a topoguided treatment of the patient as well as understanding of realistic
wherein a wavefront optimised approach is expectations. In fact, depending on age and amount
combined with treatment of preoperative corneal of accommodation in patients >40 years, presbyopia
higher order aberrations (coma and trefoil). correction can be considered, where dominant eye
Although useful in highly aberrated corneas such is treated for distance and non dominant eye is
as keratoconic eyes, the advantages in normal eyes treated for near after checking for dominance and
with lesser HOAs is limited. I still prefer SMILE as tolerance.
a treatment modality as it better preserves corneal JR: In patients above 35 years of age, we inform the
asphericity and biomechanics. patients about the onset of presbyopia after the age
RT: I am happy with the procedure. It is my LASIK of 40 years with the possibility of requiring near
procedure of choice. I do counsel the patients that as vision glasses. We have operated only those patients
it is a topography guided procedure and sometimes over 60 years of age, who have had any inadvertent
the topography image does not get captured due to refractive surprise after cataract surgery.
various reasons, in which case standard aspheric MS: In patients presenting for LASIK over the age of
excimer laser ablation protocol will be used. 35 years, I counsel them regarding monovision
OPA: Topography-guided LASIK is better than traditional treatment. Here the dominant eye is corrected for
lasik; A WaveLight topography-guided laser distance leaving the fellow eye slightly myopic for
treatment plan for an eye with Abnormal cornea or near. I prefer femtosecond LASIK as the modality
keratoconus. Such treatments may involve a blend of treatment as it affords easier retreatment with
of myopic and hyperopic ablations in different flap lift in cases wherein the patients prefer full
areas of the cornea in order to normalize it overall. correction subsequently. For patients greater than
60 years, multiple laser vision corrections for
RM: What is your experience in asymmetrical presbyopia provide promising results, provided the
refractive surgery? In which cases would you crystalline lens is clear. For eyes with cataractous
prefer corneal refractive surgery in one eye and changes I prefer a cataract extraction with
ICL in the other eye? multifocal intraocular lens implantation.
RT: I have had very few patients seeking surgical
SK: We have done surgery for a lot of patients where correction for refractive error in this age group. I
suitablity for surgery is different for each eye. counsel patients over the age of 35 about presbyopia
Commonest is anisometropia where corneal and the requirement for near vision correction after
refractive surgery suffices in one eye but not the crossing the age of 40yrs. Depending on the amount
other. Both LASIK and SMILE can be done in the of refractive error, I also explain the likelihood of
fellow eye with ICL. their requiring glasses and the number of years they
would expect to enjoy spectacle free near vision.
JR: We have done asymmetric refractive surgery in The options of slight distance undercorrection,
many cases. We would prefer corneal refractive asymmetrical binocular correction with monovision
surgery in one eye and ICL in patients with benefit, ICL, refractive lens exchange, and modern
asymmetric refractive errors. ICL will be used in techniques for presbyopic correction. So far, only
patients with thin corneas and high refractive error two patients opted for refractive lens exchange, few
(myopia and myopic astigmatism) beyond the for LASIK with distance undercorrection and few
range of laser vision correction procedures. It can for monovision and others elected to wait for better
also be used in patients with stable keratoconus or technology.
patients with prior crosslinked corneas having high OPA: Presbyopia correction or Mono vision by making
refractive error. under correction in myopic patients along with
correction of existing refractive error.
MS: I would prefer phakic intraocular lens in one eye
and laser vision correction in the fellow eye in cases RM: What is your opinion regarding LASIK in
of high anisometropia, wherein deep ablations patients with hyperopia more than +6D?
of the cornea would create a significant impact
on the corneal biomechanics or curvature with SK: The problem with LASIK in high hyperopia is
subsequently suboptimal quality of vision. higher chances of regression. Also, postoperative
keratometry is to be kept in mind (<49D). There
RT: I have not had the occasion to offer this option. are a lot of studies being performed on SMILE use
OPA: Need to analyze other factors too like Glaucoma. in hyperopia by Reinstein et al though it is not yet
FDA approved. We are waiting for long term results
RM: How do you approach patients requesting of this for hyperopia.
LASIK over the age of 35 years? What is your
experience of LASIK in patients over 60 years of JR: Lasik in patients with hyperopia more than +6D
age? can leave residual refractive error and patients
need to be counselled about it beforehand. LASIK
SK: LASIK can be considered in patients over 35 years is moderately effective for the correction of low
especially hypermetropia. Depends on the demand degrees of hyperopia. In the study by Jaycock et al,

www. dos-times.org 15

Expert Corner

there was regression throughout the 5-year follow- RM: There are situations when the RSBT and PTA
up in patients undergoing hyperopic lasik that was are normal but the pachymetry is less than
greater than would be expected as a result of aging. 500. What is your approach to such cases? And
MS: In eyes with hyperopia greater than 6D, the risk what is your preferred cut off for pachymetry to
of regression is high. I prefer combination with perform LASIK in such scenarios?
half fluence crosslinking in such cases, to reduce
the incidence of regression. Phakic intraocular SK: When all the other parameters are normal, we
lenses would be a preferred modality of treatment take cut off as 470u for corneal refractive surgery
in these eyes, provided the anterior chamber although PRK is preferred in such cases.
depth is adequate in these highly hyperopic eyes.
Another important caveat to remember is that the JR: We prefer PRK in such cases. However, our cut off
final keratometry should not exceed 49 dioptres for residual bed thickness remains as 300 microns.
(D) following hyperopic ablation profile, wherein
1D of hyperopic ablation produces roughly 1D of MS: My choice of treatment would depend on factors
keratometric steepening. including patient age and sex, history of eye rubbing
RT: Not advisable. and the refractive error to be corrected. My cut off
OPA: Lasik to be avoided in the cases of Hyperopia for minimal preoperative pachymetry for SMILE is
beyond +6 diopter lens exchange is better option 490 microns. For eyes with pachymetry between
for such cases. 475 and 490 microns I prefer surface ablation.

RM: What is your personal experience of SMILE and RT: The concept of percentage tissue altered and the
LASIK? Which procedure do you prefer more BAD are two tools that help give some clarity on
and why? In which scenarios would you prefer managing this group. If the BAD shows a normal
one over the other? cornea and % tissue altered is less than 40% and
the RBT is 300microns, and the patient has a stable
SK: Based on our experience and available data refractive error on follow up for a year, LASIK can
SMILE has an edge over LASIK due to better patient be performed. The risk factor of age < 30 remains a
matter of concern which is explained to the patient
comfort and reduced dry eye, may have lesser to help make an informed choice.
tensile strength reduction, so may reduce incidence
of ectasia, lower HOA and spherical aberration, OPA: It is recommend that preoperative screening for
better contrast sensitivity and lower dependence keratoconus and forme fruste keratoconus should
on environmental factors be performed carefully, and then PSBT should be at
LASIK is better over SMILE in a different way. least 50%.
It has been tried and tested over years. Greater
range of refractive correction especially astigmatic 20. Do you perform LASIK Xtra? What are the
correction, hyperopia, treatment of hyperopia, indications? What is your preferred protocol?
wavefront and topography guided treatment
available, lesser learning curve and faster visual RT: I do not perform LASIK Xtra as the procedure
recovery are advantages over SMILE. does rely on several assumptions and the cornea
JR: I have no personal experience of SMILE. We are is biologically unpredictable, not a mathematical
going to acquire it in PGI, Chandigarh very soon. entity. Patients do quite well with spectacles or
MS: Small Incision Lenticule Extraction is definitely my contact lenses as safer options to meet their visual
procedure of choice. The advantages of superior needs rather than add an element of further risk or
biomechanical profile, lower incidence of dry eye uncertainty.
and better preservation of corneal asphericity are
well established. LASIK is preferred in eyes with OPA: I normally avoid lasik xtra due to compromised
hyperopia, mixed astigmatism and plain astigmatic cornea and long term changes are unpredictable in
corrections for which SMILE is not commercially such cases.
available currently.
RT: My personal experience is that I like both Compiled by:
procedures. There is a factor of price differential Dr. Ritika Mukhija
which does affect patient’s choice. In theory, SMILE R.P. Centre for Ophthalmic Sciences,
is a better procedure, but in practice the literature All India Institute for Medical Sciences,
is still not fully supportive of any proven marked Ansari Nagar, New Delhi, India.
objective benefit.
OPA: Incidence of inflammation are quite less in case of
smile.
Recovery is faster in cases of smile than lasik.

16 DOS Times - March-April 2019

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Review Article

Zepto-Assisted Cataract Surgery: An Interesting
Technology

Dr. Gunjan Budhiraja MBBS, DNB, DO, FICO (II), Dr. Vinay Garodia MBBS, MD(AIIMS), DNB, FRCS(Ed.)

Synergy Visitech Eye Centre, South Extension-2 , New Delhi, India.

Cataract has been documented to be the most How does it work?
significant cause of bilateral blindness and
contributes 50-80% for that in India1,2. Number of A rapid series of electrical pulses totaling 4 ms in duration
cataract surgeries have increased to 3.9 million per is used to create the capsulotomy.
year in 2003 as compared to 1.2 million in 1980s,
which will further increase to around 32 million Phase transition of water molecules trapped between the
by the year 2020 as estimated by World Health Organisation capsule and nitinol edge causes mechanical cleavage of the
(WHO)3,4. stretched capsular membrane circumferentially all at once.
Phacoemulsification has become the Modern day surgery
of choice for cataracts,for most of the surgeons. Unlike the sequential circular path of a manual
The most critical step in cataract surgery is capsulorhexis, capsulorhexis or Femtosecond laser capsulotomy (FSLC),
or continuous curvilinear capsulotomy which is required for the PPC technology mechanically and simultaneously cuts all
lens removal and also to get a route for placement of IOL in the 360° of the apposed capsule without cauterizing it, creating
bag. Continuous curvilinear capsulorhexis of 5.2 mm size6.
Proper size, shape and centration of capsulorhexis helps
in the proper hydrodissection of lens, its removal, cleaning of Theoretically, a smaller diameter capsulotomy would have
cortical matter, IOL centration and also inhibit post capsular a thinner and weaker edge compared with one with a larger
opacification. 5- to 5.5-mm diameter. This relationship between capsulotomy
In the era of multifocals, toric and extended depth IOLs, diameter and edge strength has been experimentally confirmed
perfect capsulorhexis has become a necessity for better in porcine eyes for capsulotomy diameters between 4 and 5.5
placement and stability of IOL in the bag.
Several techniques are used to make a capsulorhexis in
cataract surgery as needle cystotome, Utrata capsulorhexis
forceps, microincision capsulorhexis forceps, femtosecond
Laser, etc.5

What is Zepto technology? Figure 1: Showing Zepto Console.

Zepto precision nano-pulse capsulotomy device (Mynosys
Cellular Devices; Fremont, CA, USA) is Food and Drug
Administration approved, a disposable capsulotomy device that
uses low-energy pulses to create a precise central capsulorhexis,
independent of pupil size, corneal clarity, or lens density.

The PPC device name was chosen because, in the metric
scale, Zepto is 1 million times smaller than femto. Both the
small size of the instrument and the several millisecond speed
of capsulotomy creation inspired this name.

What is the actual design of the device? Figure 2: Showing (i) handpiece (ii) Vacuum Syringe and (iii) Connector
(order of top to bottom).
A disposable handpiece and nanoengineered capsulotomy
tip are powered by a small console to automatically and
instantaneously create a perfectly circular capsulotomy of a
precise predesigned diameter (Figure 3).

The tip consists of a circular nitinol ring covered by a thin
soft, clear silicone suction cup (SC)‐shaped like a miniature
inverted frying pan. Nitinol is a superelastic shape memory
alloy which means that a nitinol ring for a 5–5.5 mm diameter
capsulotomy can be can be made to fit through a small clear
corneal incision (Figure 4).

40 DOS Times - March-April 2019 Budhiraja G. et al. Zepto-Assisted Cataract Surgery: An Interesting Technology

Review Article

Figure 3: Showing Zepto handpiece.

mm.7 (Figure 5).

INDICATIONS OF ZEPTO Figure 4: Image showing the Zepto Device inserted into the eye from a small corneal incision.
CAPSULOTOMY:
Comparison of Femto vs Zepto
Precision nano-pulse capsulotomy
device is a relatively inexpensive and FEMTO ZEPTO
disposable capsulotomy device that uses
low-energy pulses to create a precise 1. Size of machine Large machine , requires Compact machine , less
central capsulorhexis, independent of
pupil size, corneal clarity, or lens density. more space space needed

Zepto capsulotomy device can be 2. Surgeon’s convenience Eye docking required, Same sitting and same
very helpful in:-
1. White cataract cases creates surgical challenges incision works
2. Small pupils
3. Subluxated cataract cases 3. Capsulotomy edge strength Weaker5 Stronger
4. Infantile cataracts
5. Large central corneal opacity 4. Anterior capsular tears Higher in number7 Lesser

involving visual axis. 5. Cost effectiveness High cost per case Relatively cheaper
6. Morgagnian cataracts
7. Toric IOL placement. 6. Additional Pupil expansion Difficult to use in same Can be combined in
8. Other cases where a successful devices surgery same sur-gery

capsulorhexis is difficult. 7. Learning curve Longer5 Shorter

Advantages of Zepto: 4. Krasnov MM. Laser-phakopuncture in the

The higher strength of the PPC treatment of soft cataracts. Br J Ophthalmol
capsulotomy edge is likely due to its
unique morphology that is very different 1975;59:96-8.
from the edges produced by manual
CCC and FSLC. On Scanning electron 5. Thompson VM, Berdahl JP, Solano JM, Chang
microscopy (SEM) of human cadaver
capsules, the PPC capsulotomy edge DF. Comparison of manual, femtosecond
appears to be microscopically everted to
present the underside of the capsule as laser, and precision pulse capsulotomy edge
a smooth, rounded functional edge that
circumferen-tially lines the capsulotomy tear strength in paired human cadaver eyes.
opening during surgery.
Ophthalmology 2016;123:265-74.
Complications of Zepto
6. Chang DF, Mamalis N, Werner L
Although Zepto is a very simple
technique with virtually no side-effects Precision Pulse Capsulotomy: Preclinical
or complications, sometimes one may
encounter a few difficulties with this Safety and Performance of a New
technique like:
1. Difficult entry into shallow anterior Capsulotomy Technology. Ophthalmology.

chamber. 2016 Feb; 123:255-64.
2. Incomplete rhexis.
3. Anterior capsular tears. 7. Packer M, Teuma EV, Glasser A, Bott S.
4. Zonular damage. Defining the ideal femtosecond laser
5. Risk of capsulotomy decentration.
Figure 5: Image showing well centered stable capsulotomy. Br J Ophthalmol 2015;99:
Conclusion rhexis margin of size 5.25 mm, without the use
of trypan blue. 1137–42.
The Zepto PPC technology creates
a precise circular anterior capsulotomy with intumescent or brunescent lenses, 8. Abell RG, Davies PE, Phelan D, Goemann
used as part of the normal surgical zonulopathy, or small pupils.
sequence. The technique holds promise K, McPherson ZE, Vote BJ, et al. Anterior
for complicated eyes such as those
capsulot-omy integrity after femtosecond

laser-assisted cataract surgery.

Ophthalmology 2014;121:17-24.

REFERENCES Correspondence to:
Dr. Gunjan Budhiraja
1. Mohan M. National Survey of Blindness-India. Synergy Visitech Eye Centre,
NPCB-WHO Report. New Delhi: Ministry of South Extension-2,
Health and Family Welfare, Government of New Delhi, India
India; 1989.

2. Mohan M. Collaborative Study on Blindness
(1971-1974): A report. New Delhi, India:
Indian Council of Medical Research;1987.
pp.1–65.

3. Jose R, Bachani D. Performance of cataract
surgery between April 2002 and March
2003. NPCB-India. 2003;2:2.

Budhiraja G. et al. Zepto-Assisted Cataract Surgery: An Interesting Technology www. dosonline.org 41

Review Article

Cataract Surgery in Operated Trabeculectomy
Patients: Pearls and Pitfalls

Dr. Vinita Ramnani MS
H.o.d. Eye Departement, Bansal Hospital, Shahpura, Bhopal, Madhya Pradesh, India.

Cataract surgery in operated trabeculectomy is Corneal topography can be done to plan placement of incision
required in many instances like as a part of two to minimize postoperative astigmatism. It is very common to
staged surgery, first trabeculectomy then cataract see shallow anterior chamber and poorly dilating pupils with
surgery or Cataract surgery needed in immediate posterior synechia. The type and density of cataract need
postoperative period following trabeculectomy to be kept in mind when operating on eyes with previous
due to lens touch and cataract development or trabeculectomy. Pseudoexfoliation, weak zonules and mobile
cataract surgery required for senile cataract as normal aging bag require extra care during the manipulation of the lens and
process after long time.The Advanced Glaucoma Intervention the need of an endocapsular ring. Detailed fundus examination
Study 1 reported increase in risk of any type of cataract is a must, but sometimes due to a dense cataract the view is
following trabeculectomy as high as 78%. The major risk hampered and a B-scan ultrasound is needed to note the gross
factors for cataract formation are complications following retinal abnormalities and cupping. Biometry for such patients
trabeculectomy of flat anterior chamber and postoperative is difficult and unreliable due to shallow anterior chamber
inflammation both can increase the risk of cataract formation and over hanging blebs with high cylinders. It is mandatory
by 14%. Cataract surgery in operated trabeculectomy is to do a glaucoma evaluation in depth with IOP measurement
challenging because surgery can lead to several complications preferably by applanation, diurnal variation whenever possible,
in the already compromised eye. The main objective of the look for hypotony, gonioscopy to check for trabeculectomy
cataract surgery is to restore optimal visual function without window, fundus photo to document glaucomatous changes and
compromising bleb function. Outcome of phacoemulsification preoperative perimetery with 10-2 and macular program for
in eyes with a filtering bleb depends on multiple factors. The advanced cases.This preoperative details help in anticipating
status of previous surgery has a direct effect on the success or intraoperative difficulties and in planning the case to enhance
complexity of phacoemulsification and its overall benefit to the postoperative results.
patient. Therefore justify the decision of cataract surgery and
always look for risks and benefits of doing cataract surgery INTRAOPERATIVE MEASURES
for such patients. It is important to have proper preoperative
counseling, explain prognosis to such patients especially the The ideal anaesthesia for such patients is topical and
risk of wipe out in advanced glaucoma patients and do a detailed a retrobulbar anaesthesia should not be given. Whenever
glaucoma evaluation. But sometimes it is difficult to visualize needed a peribulbar block can be given with caution and a
glaucoma progression due to the presence of cataract. Cataract super pinky should be avoided. IOP control before surgery
surgery in operated trabeculectomy patients is considered to helps in reducing positive pressure during surgery. Due care
have an adverse effect on long-term survival of bleb and special is taken during surgery to avoid bleb handling and the main
modifications are required to maintain the IOP. According to or side port incisions should be made away from the bleb.
literature 10–61% of trabeculectomies fail by 12–36 months. There is no statistically significant difference found between
A gap of minimum six months between two surgeries increases temporal clear corneal or temporal scleral tunnel incisions. The
the chances of bleb survival. site of the filtering bleb is usually superior hence a temporal
or slightly inferotemporal clear corneal incision is preferred.
PREOPERATIVE CONSIDERATIONS Extra caution must be taken during paracentesis as there is
a risk of damage to iris or anterior capsule due to a shallow
Preoperative evaluation should include a thorough clinical anterior chamber. Compromised corneal endothelium should
examination and investigations. Important aspects of the be protected with dispersive viscoelastics, chilled balanced salt
evaluation include: a detailed history that includes type and solution plus and use of Simmons soft shell technique. Trypan
date of glaucoma surgery and drug intake, best corrected visual blue staining not only facilitates capsulorhexis but stains the
acuity after trabeculectomy and following development of filtering bleb to provide an intraoperative assessment of the
cataract. A special mention of details of the filtering bleb like site, bleb function which helps in deciding if a simultaneous internal
size, thickness and functioning of bleb by slit-lamp examination revision of bleb is required. Copious use of high molecular
and anterior segment optical coherence tomography (ASOCT) weight viscoelastics and minimal and gentle anterior chamber
or ultrasound bimicroscopy (UBM) is important and helps in manipulations can prevent any inadvertent trauma to the
planning incision site and size. Corneal status must be noted bleb; minimize inflammation by increasing the chances of bleb
as previous surgery can give rise to low corneal endothelial survival. Such patients can have a floppy iris, pupillary miosis
cell count which is measured by specular biomicroscopy. and a risk of iris prolapse due to positive pressure so careful

Ramnani V. Cataract Surgery in Operated Trabeculectomy Patients: Pearls and Pitfalls www. dosonline.org 43

Review Article

iris manipulation is needed to reduce failure like imminent scar formation, 1. Delay cataract surgery at least 6
inflammation and enhance the bleb months till the bleb gets matured.
survival. Use of iris hooks, pupil expansion corkscrew vessels and encapsulation
rings or other mechanical means 2. Assess bleb function and pupillary
like stretch pupilloplasty or multiple and if needed 5 mg of subconjunctival dilatation before surgery.
small sphincterotomies, injection of
high molecular weight viscoelastics, 5-FU injections can be given. Look for 3. Minimize surgical trauma and
synechiolysis, or stripping of pupillary wound leak with a flat or shallow anterior conjuctival, iris and bleb handling.
membranes may be performed when chamber, hypotony and choroidal
required. These eyes tend to have a 4. Use small clear corneal temporal
shallow anterior chamber so the vacuum effusion. Such patients are also at a risk incision away from the bleb.
setting should be kept on the lower sides of postoperative inflammation, uveitis
and the height of the infusion bottle should and subsequent bleb failure; therefore 5. Reassess bleb function again on
be increased to prevent collapse of the completion of the cataract surgery
anterior chamber. Phacoemulsification vigorous use of topical steroids is indicated and revise if needed.
should be performed in the capsular bag to reduce postoperative inflammation
by standard stop and chop method. A with caution as topical steroids may 6. Look for IOP spikes and postoperative
thorough cortical clean-up is mandatory inflammation and treat aggressively.
because retained cortical matter can result in IOP spikes, especially in steroid
excite inflammation and can jeopardise 7. Observe for early signs of bleb failure
the health of the bleb. Be aware of responders. Topical NSAIDS may be and intervene in time.
pre-existing zonular weakness and considered to minimize inflammation for
extra caution must be taken to prevent long term use and in steroid responders. CONCLUSION
posterior capsule rupture and vitreous There is a risk of visual fields progression
loss otherwise the whole purpose of therefore generate new base line fields Phacoemulsification in operated
doing the surgery will be defeated. following cataract surgery. There are trabeculectomy patients requires due
care at all steps from preoperative
In case of posterior capsular chances of high cylindrical power and evaluation to intraopreative caution and
rupture, sulcus fixation of a hydrophobic good postoperative care to avoid any
acrylic multipiece (3 pieces) IOL can be refractive surprises following cataract potential complications and to enhance
used, but make sure that the anterior the visual outcome. All the key points
chamber is completely free of vitreous surgery and it can take slightly longer for given above will definitely help to achieve
strands. Avoid use of PAMA lens and final postoperative glasses prescription a long term successful outcome with
In-the-bag implantation of a square due to delayed healing. Always look for regular followups.
edge, single piece foldable, aspheric,
hydroacrylic intraocular lens are best the nightmare complications of blebitis REFERENCES
suited for these patients. Multifocal IOLs
are contraindicated in glaucoma patients and endophthalmitis. 1. Dada T, Bhartiya S, Baig NB , Cataract
with significant visual field and contrast Surgery in Eyes with Previous
sensitivity loss. To prevent early IOP Bleb failure is the main area of Glaucoma Surgery: Pearls and Pitfalls J
spikes thorough viscoelastic removal is Curr Glaucoma Pract. 2013; 7: 99–105.
mandatory especially from beneath the concern in a case of cataract surgery
IOL. At the end of the surgery inject BSS 2. Husain R, Liang S, Foster P J, et al
into the anterior chamber to asses bleb in operated trabeculectomy, most bleb Cataract Surgery after Trabeculectomy,
function and If the bleb is not raised an The Effect on Trabeculectomy Function,
internal revision may be performed by failure occurs soon after cataract surgery. Arch Ophthalmol. 2012; 130:165-170.
passing a cyclodialysis spatula to the
subtenon space through the wound or Several factors are associated with an 3. AGIS (Advanced Glaucoma Intervention
paracentesis port to the sclerostomy Study) Investigators. The Advanced
fistula and by gentle movements below increased risk of loss of IOP control like Glaucoma Intervention Study (AGIS):
the scleral flap to re-establish bleb 8. Risk of cataract formation after
function. patients under 50 years of age are more trabeculectomy. Arch Ophthalmol
2001;119:1771-1779.
POSTOPERATIVE CARE likely to undergo a trabeculectomy fail
due to a more active fibrotic tendency, a 4. Dada T, Muralidhar R, Sethi HS.
Such patients needs more regular preoperative IOP greater than 10 mmHg Staining of filtering bleb with trypan
follow ups and care in comparison blue during phacoemulsification. Eye
to routine cataract cases to check for or early IOP spikes of more than 25 mm (Lond) 2006;20:858-859.
postoperative IOP fluctuations and
bleb failure. Early bleb failure and Hg. If cataract surgery is performed in less 5. Musch DC, Gillespie BW, Niziol LM, Janz
postoperative IOP spikes can be managed NK, Wren PA, Rockwood EJ, Lichter
by digital massage and using appropriate than 6 months after trabeculectomy, the PR; Collaborative Initial Glaucoma
antiglaucoma medication. Careful bleb is more susceptible to inflammation Treatment Study Group. Cataract
attention is given to signs of early bleb and chances of bleb failure are high, extraction in the collaborative initial
glaucoma treatment study: incidence,
excessive iris manipulation can cause risk factors, and the effect of cataract
progression and extraction on clinical
breakdown of the blood-aqueous barrier and quality-oflife outcomes. Arch
and increase inflammation, previous Ophthalmol 2006;124:1694-1700.
use of topical medications, race, etc. The
6. Sharma TK, Arora S, Corridan PG.
use of MMC in the trabeculectomy prior Phacoemulsification in patients
with previous trabeculectomy:
to cataract surgery was not found to be role of 5-fluorouracil. Eye (Lond)
2007;21:780-783.
associated with an increased chance
of bleb success. Phacoemulsification 7. Singh M, Chew PT, Friedman DS, Nolan
provides better long-term IOP control WP, See JL, Smith SD, Zheng C, Foster
PJ, Aung T. Imaging of trabeculectomy
than ECCE. Literature shows variability blebs using anterior segment optical
coherence tomography. Ophthalmology
in short-term and long-term effects of 2007;114:47-53.
phacoemulsification on a functioning
bleb. Various studies proved that after

cataract surgery the IOP in patients with

a functioning trabeculectomy is generally

increased up to 3.1 mmHg. Duration of

steroid use following cataract surgery can

be an important variable as well.

Cataract surgery in Eyes with

Previous trabeculectomy: Pearls and

Pitfalls

44 DOS Times - March-April 2019 Ramnani V. Cataract Surgery in Operated Trabeculectomy Patients: Pearls and Pitfalls

Review Article

8. Park HJ, Kwon YH, Weitzman trabeculectomy. J Cataract Refract Surg 17. Swamynathan K, Capistrano AP, Cantor
LB, WuDunn D. Effect of temporal
M, Caprioli J. Temporal corneal 2002;28:425-430. corneal phacoemulsification on
phacoemulsification in patients with intraocular pressure in eyes with prior
filtered glaucoma. Arch Ophthalmol 13. Casson RJ, Riddell CE, Rahman R, Byles trabeculectomy with an antimetabolite.
1997;115:1375-1380. Ophthalmology 2004;111:674-678.
D, Salmon JF. Longterm effect of cataract
9. Chen PP, Weaver YK, Budenz DL, Feuer 18. Sałaga-Pylak M, Kowal M, Żarnowski
surgery on intraocular pressure T. Deterioration of filtering bleb
WJ, Parrish RK 2nd. Trabeculectomy morphology and function after
after trabeculectomy: extracapsular phacoemulsification. BMC Ophthalmol
function after cataract extraction. extraction versus phacoemulsification. 2013;23:13-17.
J Cataract Refract Surg 2002;28:2159-
Ophthalmology 1998;105:1928-1935. Correspondence to:
2164. Dr. Vinita Ramnani
10. Manoj B, Chako D, Khan MY. Effect H.o.d. Eye Departement,
14. Casson R, Rahman R, Salmon JF. Bansal Hospital, Shahpura, Bhopal,
of extracapsular cataract ex-traction Phacoemulsification with intraocular Madhya Pradesh, India
and phacoemulsification performed lens implantation after trabeculectomy.
after trabeculectomy on intraocular
J Glaucoma 2002;11:429-433.
pressure. J Cataract Refract Surg
15. Shingleton BJ, O’Donoghue MW, Hall
2000;26:75-78. PE. Results of phacoemulsification in
eyes with preexisting glaucoma filters.
11. Rebolleda G, Muñoz-Negrete FJ. J Cataract Refract Surg 2003;29:1093-
Phacoemulsification in eyes with
functioning filtering blebs: a 1096.
prospective study. Ophthalmology 16. Liu Y, Ge J, Cheng B. Phacoemulsification

2002;109:2248-2255. with silicone foldable intraocular lens

12. Derbolav A, Vass C, Menapace R, implantation through a small incision
in glaucomatous eyes after filtering
Schmetterer K, Wedrich A. Long- surgery. Zhonghua Yan Ke Za Zhi
term effect of phacoemulsification
on intraocular pressure after 2000;36:435-437. (Chin).

Ramnani V. Cataract Surgery in Operated Trabeculectomy Patients: Pearls and Pitfalls www. dosonline.org 45

Review Article

IOL Power Calculation Formulas: A Major Review

Dr. Sandhya Makhija, Dr. Rukhsana
Department of Ophthalmology, Sant parmanand Hospital, Delhi, India

The prediction of refractive outcomes after Axial length
cataract surgery has steadily improved, with Axial length is defined as the distance from anterior corneal
more recent intraocular lens (IOL) power
formulas generally outperforming those of prior surface to retinal pigment epithelium. Can be performed using
generations1,2. Calculation of the dioptric power optical or ultrasound method.
of intraocular lenses [IOL] started with ridley3
who on implanting an IOL for the first time committed an error A constant
and left the patient highly myopic [-18 sph, -6.00 cyl at 120].
Fyoderov et al4 first estimated the optical power of an IOL using A constant depends upon multiple factors: IOL dependent
vergence formula in 1967. which depends upon type, material, position and surgeon
dependent which depends upon technique and placement of
Intraocular lens power calculation falls into two major incision. Once fixed for a particular surgeon, IOL and machine
categories: The empirically determined regression formulas for the scan, it is applied as a constant for the appropriate
and theoretical formulas. formula. It approximately varies with a ratio of 1:1 with the IOL
formula. The most common a constants used are:
Regression formulas • Anterior chamber lenses - 115.0-115.3
• Posterior chamber lenses in the sulcus - 115.9-117.2
Sanders - Retzlaff-kraff [SRK] formulas are based on • Posterior chamber lenses in the bag - 117.5-118.8
mathematical analysis of a large sampling of postoperative
results in adults. He found that dioptric power of the IOL ELP
depends upon the corneal power and axial length to achieve It denote the position of lens in the eye, specifically the
emmetropia. This formula was universally used because it was
simple and ACD was replaced by A constant for each IOL style. distance that the principal plane of the IOL will sit behind the
cornea
P= A -2.5L - 0.9 K
P: IOL constant in diopters In accordance with these variables formulae can be divides
L: axial length of eye in mm as:
K: average K reading
Theoretic Formulas are based on geometric optics Generation Table 1
and there are six variables in theoretic formulas which are First
described below: Description
Second
Variables in theoretic formula Third Before 1980, ELP was a constant of 4mm
Fourth in every patient and every lens{ mainly for
• Net corneal power (K) ACIOL}
• Axial length (AL)
• IOL power (IOLP) In 1980, binkhorst used AL, single variable
• Effective lens position (ELP) predictor, as a scaling factor for ELP5
• Desired refraction (D Post Rx)
• Vertex distance (V) In 1988, two variable predictor, K & AL
improved accuracy of ELP6
The only variable that cannot be chosen or measured
preoperatively is ELP. The improvements in IOL power In 1995, olsen & co workers improved ELP
calculations over the past 30 years are a result of improvements accuracy by adding two variables : preop ACD
in the predictability of the variable ELP. & lens thickness7

Corneal power Using Gaussian reduction equation, the formula for
calculating IOL power in accordance with the refractive index:
The corneal power depends upon steepness of the cornea.
The cornea is assumed to be a perfect spherical optical mirror P= [nv/ [ AL-C ] } - { K/ [1- Kx C/nA] }
with a fixed anterior to posterior corneal curvature ratio. The P= power of the target IOL [in diopter [D]
cornea then act as a perfect convex mirror leading to a virtual K= average dioptric power of the cornea in diopter
image of the target, corneal curvature is predicted from this AL = axial length of eye in mm
which is then used to measure corneal power. C = ELP in mm
nv= index of refraction of the vitreous
nA = index of refraction of the aqueous
The first-generation theoretical IOL formulas such as

Makhija S. et al. IOL Calculation Formulas: A Major Review www. dosonline.org 47

Review Article

1 mm causes a 1.5 D change in the final
refraction.

Holladay et al.16 discovered that
the anterior segment and posterior
segment of the human eye often are
not proportional in size, which causes
significant error in the prediction of
the ELP in extremely short eyes (axial
length <20 mm). Several additional
measurements of the eye were taken, but
only seven preoperative variables (axial
length, corneal power, horizontal corneal
diameter, anterior chamber depth, lens
thickness, preoperative refraction, and
age) were found to improve significantly
the prediction of ELP in eyes of axial
length in the range 15-35 mm.

Figure 1: diagrammatic representation with reduced optics. IOL formula using holladay17

the Fyodorov, Colenbrander, Hoffer, D1 = AI- 0.9K - 2.5L - Rs y D = 1336
D1 = IOL power in diopters Br - acor - 0.001Rs
assume a constant position of the IOL, or AI = IOL constant in diopters
K = Average K reading [ v[Br- acor] +a acor
postoperative anterior chamber depth L = Axial length in mm __________________________________________
Rs= Desired post operative [acor -d -SF] { Br - d - SF - 0.001Rs
(ACD) in all eyes, regardless of their AL.
refraction in diopters [ v[Br - d - SF] + a[ d+ SF] r]}
Since the measured postoperative ACD y = 1.00 for AI - 0.9K- 2.5L <14MM D= IOL power in diopter
Y = 1.25 for AI - 0.9K- 2.5 L > 14MM acor = corrected axial length in mm
was found to be directly proportional to v = vertex distance in mm
The originators of the SRK formulas SF =Holladay surgeon factor in mm
the AL of the eye (longer eyes had larger brought their retrospective analytic r= 337.5/K
approach to develop a third-generation B= nv / [nc -1 ] with nv = 1.336 and
ACDs), these formulas were less accurate IOL formula. The SRK/T formula is a
nonlinear theoretical optics formula nc =1.333333
for long or short eyes8. empirically optimized for postoperative a = 1.0 / [nc - 1 ]
anterior chamber depth based on axial d = ACD = 0.56 + Rag -√ [Rag 2 - AG2
Several second-generation length, retinal thickness correction for
AL, and corneal refractive index12. It /4]
theoretical formulas emerged, such as the thus combines advantages of theoretical Rag = r for r≥ 7mm
and empirical analysis. For extremely AG = 0.533 L for AG ≤ 13.5mm
Hoffer formula that replaced the constant long eyes (>28 mm), the SRK/T seems AG = 13.5mm for AG > 13.5mm
to be significantly more accurate than
ACD with one that included a correction regression formulas13. Hoffer also developed a third-
generation IOL formula8. He speculated
for AL9. Thus, with second-generation Holladay and associates also on the relationship between ACD and
consider that the ACD might vary not AL and developed an expression that
formulas, ACD was no longer a constant only with the AL but also with the corneal resulted in an S-shaped curve that fit
curvature14. Their formula modified the his impression of what this relationship
in all eyes but rather varied with AL. ACD based on the AL, and also based should be. This formula deepened the ACD
on the corneal height (distance from with increasing AL and with increasing
The superiority of SRK regression the cornea to the IOL’s first principal corneal curvature. This modification of
plane). This formula was shown to be the ACD, added to his previous Hoffer
formula over the classical theoretical significantly more accurate than previous formula, has become known as the Hoffer
theoretic formulas and the SRK II15. Q formula.
formula has been shown in different Holladay formula uses S factor which is
the distance between the iris plane and HOFFER Q FORMULA:
reports by sanders et al.10 These authors the IOL optic plane. A change in the true
post-operative AC depth will affect the D= [ 1336/[L- d - 0.05]
point out that A constant of SRK formula refractive status of the eye. A change in - [1.336/[1.336/[K + Rs] - [ d +

must be individualised for each type 0.05]/1000]
D = IOL power in diopter
of lens and manufacturer to achieve d = ACD in mm
where ACD = pACD+0.3[L-23.5]
maximum precision in calculating the +[Tan k]2 + [0.1 M[23.5-L]2
x [Tan[0.1[G-L]2 ] - 0.99166
IOL power. In adult eyes, the SRK formula The personalized ACD [p ACD] is set
[first generation linear regression equal to the manufacturers ACD constant.

formula] is most appropriate for eye with

AL [22.5-25.0], the formula does not work

well for long eye [> 25mm] and short

eye [<22.5mm]. This under correct short

eyes and overcorrect long eyes. The SRK

formula was modified and emerged as
SRK II This was a simple modification of

the original SRK formula in which the ‘‘A’’
constant is modified according to the AL

of the eye11.

SRK II formula

48 DOS Times - March-April 2019 Makhija S. et al. IOL Calculation Formulas: A Major Review

Review Article

Historical theoretic Table 2 refractive error to create the Holladay
Historical regressive 2 formula (Holladay JT: Holladay IOL
Modern theoretic Fyodorov [1967], colenbrander, 1972, hoffer 1974, binkhorst Consultant Computer Program. Houston,
Holladay 1988 1975 TX, 1996). In adults, the Holladay formula
is considered to be most accurate for
SRK/T 1990 SRK 1980, SRK II [1988] both formulas are outdated and eyes with an axial length between 22
Hoffer Q 1992 SRK/T is used currently. and 26 mm. The Hoffer Q formula is
considered to be most accurate for short
Holladay 2 1996 Description eyes (<24.5mm). The SRK/T formula
is considered optimal for long eyes
Basic theoretic formula which calculates the corneal height (>26mm).
(issued by Olsen) added to the corneal thickness (0.56) and
an IOL/surgeon specific constant (the SF), to calculate the ELP Special circumstances

Basic theoretic formula using Paediatric age group:
Olsen method for predicting ACD. Refractive growth after IOL

Basic Hoffer formula [1974]. Uses Q formula to predict ELP implantation in infants and children
which is dependent upon AL and K, using a personalized ACD. cannot be predicted accurately (large
As accurate as the Holladay 1 formula and superior in short standard deviation) and current IOL
eyes. formulas vary in their predictive
outcomes.
Intend to improve short eye calculation involve measured
anterior chamber depth, lens thickness, corneal diameter Superstein et al, however, found that
and is helpful in adults requiring 30 D of power to achieve patients with pseudophakia between 2
emmetropia18. and 20 years of age have only a minor
trend toward myopia and show less
Table 3: Choices of formula myopic shift than patients with aphakia19.
AL and K reading must be measured
Circumstances Choice of formula in general anaesthesia and immersion
technique is more accurate. Currently
AL <20mm HolladayII/ Hoffer Q all infants above 2 months require IOL
implantation. The development of the eye
20-22mm Hoffer Q necessitates initial undercorrection to
avoid later myopic shift.
22-25mm SRK/T, HofferQ, HolladayI
After posterior segment
25-26mm Holladay I surgery

>26mm SRK/T The velocity of sound in silicone
is slower than in vitreous which must
Myopic Lasik Haigis L be corrected for measurment of AL
accurately. silicone in the eye act as a
Piggy Back Holladay's Refractive Formula negative lens and will cause the eye to
become hyperopic by 2-3D [Planoconvex
IOL] or 3-6D [Bioconvex IOL] hence the
IOL power must be increased [adjusted
by 3-5D]. Optical method is more accurate
for measurment of AL in silicone filled
eye22.

Figure 2: Different formulas correlating with axial length. After Refractive surgery

pACD is derived from A constant if chosen. his formula by including consideration The Ascrs Postrefractive Iol
p ACD = ACD - Const= 0.58357 of white-to-white corneal diameters, Calculator:
x A const - 63.896 preoperative anterior chamber depth,
To improve accuracy in short, lens thickness measurements, as well The ASCRS post refractive IOL
as the patient’s age and preoperative calculator is a free online tool that
hyperopic eyes, Holladay further modified enables surgeons to automatically
generate a range of IOL power predictions
by entering historical data (pre- and
post-LASIK/PRK refraction), biometry
measurements, and K mea-surements
(taken by any one of a variety of devices).
Since its introduction is online, this
calculator has been evaluated by several
studies23, .24-27

Makhija S. et al. IOL Calculation Formulas: A Major Review www. dosonline.org 49

Review Article

Table 4 Estimation of optical power of the
intraocular lens. Vestn Oftalmol 1967;
Age % of IOL power calculated for emmetropia 80:27-31.
5. Olsen T, Corydon L, Gimbel H.
0-2 month Controversial implantation Intraocular lens power calculation with
an improved anterior chamber depth
2 month - 2 year 80 [ 20% undercorrection] prediction algorithm. J Cataract Refract
Surg 1995;21:313–9.
> 2 year 90 [ 10% undercorrection] 6. Hoffer KJ. Modern IOL power
calculations: Avoiding error and
Note: These corrections are to be made on the newer generation formulas like SRK/T.20,21 planning for special circumstances.
Focal Points: Clinical Modules for
Figure 3. Box-plot of intraocular lens (IOL) power prediction errors (PEs) with optical coherence Ophthalmologists. San Francisco:
tomography (OCT)-based IOL formula (OCT), True K No History (True-K), Wang-Koch-Maloney American AcademyofOphthalmology;
(WKM), Shammas, Haigis-L, Average of the 5 formulas (Avg5), and Average of 3 formulas (OCT, 1999, module 12.
Haigis-L, and True-K No History) (n ¼ 104 eyes). D ¼ diopters. 7. Haigis ‘vv. The Haigis formula.
Intraocular Lens Power Calculations.
ASCRS website - OCT based IOL power calculation = Shammas H], ed. Thorofare, NJ: Slack
Highest Accuracy Inc; 2003:chap 5, pp 41-57.
• www.ascrs.org [American society of 8. Hoffer KJ: The Hoffer Q formula: a
cataract and refractive surgery] - Barett True-K formula23 comparison of theoretic and regression
- WKM Wang-Koch-Maloney36 formulas. J Cataract Refract Surg
• www.apacrs.org [asia pacific - HAIGIS L 19:700--712 (Errata published in
association of cataract and refractive - Shammas 20:677, 1993).
society] 9. Holladay JT, Prager TC, Chandler TY,
REFERENCES et al: A three-part system for refining
1: previous data required intraocular lens power calculations. J
Aramberri28 [Double K method = use 1. Kane JX, Van Heerden A, Atik A, Cataract Refract Surg 14:17--24, 1988.
Petsoglou C. Intraocular lens power 10. RetzlaffJ. A new intraocular lens
preop K to predict ELP and current total formula accuracy: comparison of 7 calculation formula. An itraocular
mean K for vergence calculation] formulas. J Cataract Refract Surg. implant SocJ 1980;6:148-52
2: NO data required 2016;42:1490-1500. 11. Sanders DR, Retzlaff J, Kraff MC:
Comparison of the SRK IIformula and
Methods that do not rely on historical 2. Cooke DL, Cooke TL. Comparison of other second generation formulas. J
data. These methods mainly falls into 2 9 intraocular lens power calculation CataractRefract Surg 14:136--41, 1988.
categories: (1) regression formulas29,30,31 formulas. J Cataract Refract Surg. 12 Retzlaff JA, Sanders DR, Kraff MC:
that adjust the measured K values, or 2016;42:1157- 1164. Development of the SRK/T intraocular
(2) formulas that are based on direct lens implant power calculation formula.
measurements of the anterior and 3. Ridley H. Intra ocular acrylic J Cataract Refract Surg 16:333--40,
posterior surfaces of the cornea measured lenses. A recent development 1990.
either by a Scheimpflug32 device or by an in the surgery of cataract. Br J 13. Sanders DR, Retzlaff JA, Kraff MC, et
OCT-based technology33,34,35. Ophthalmol[1973:57:735-40. al: Comparison of the SRK/T formula
and other theoretical and regression
4. Fedorov S.N., Kolinko A.I., Kolinko A.I.: formulas. J Cataract Refract Surg
16:341--6, 1990.
14. Holladay JT, Prager TC, Chandler TY,
et al: A three-part system for refining
intraocular lens power calculations. J
Cataract Refract Surg 14:17--24, 1988/
15. Hoffer KJ: Lens power calculation for
multifocal IOLs, in Maxwell WA, Nordan
LT (eds): Current Concepts of Multifocal
Intraocular Lenses. Thorofare, NJ,
Slack, 1991, pp. 193--208.
16. Holladay J.T., Gills J.P., Leidlein J.,
Cherchio M.: Achieving emmetropia in
extremely short eyes with two piggy-
back posterior chamber intraocular
lenses. Ophthalmology 1996;
103:1118-1123.
17. Holladay JT: Standardizing constants
for ultrasonic biometry, keratometry,
and intraocular lens power
calculations. J Cataract Refract Surg
23:1356--70, 1997.
18. Holladay JT, Prager TC, Chandler TY,
et al: A three-part system for refining
intraocular lens power calculations. J
Cataract Refract Surg 14:17--24, 1988.
19. Superstein R, Archer SM, Del Monte MA:
Minimal myopic shift in pseudophakic
versus aphakic pediatric cataract
patients. J AAPOS 6:271--6, 2002.
20. Van Balen AT, Koole FD. Lens
implantation in children. Ophthalmic

50 DOS Times - March-April 2019 Makhija S. et al. IOL Calculation Formulas: A Major Review

Review Article

Pediatr Genet 1988;9:121–125. the Ocular MD IOL calculator. Clin by Fourier-domain optical coherence
21.. Dahan E, Drusedau MUH. Choice of Ophthalmol. 2011;5:1409‒1414. tomography. J Cataract Refract Surg.
27. Canto AP, Chhadva P, Cabot F, et al. 2012;38:589‒594.
lens and dioptric power in pediatric 34. Huang D, Tang M, Wang L, et al. Optical
pseudophakia. J Cataract Refract Surg Comparison of IOL power calculation coherence tomography-based corneal
1997;23(Suppl.):S618–S623. power measurement and intraocular
22. Thomas C. Prager, PhD, MPHa,*, David R. methods and intraoperative lens power calculation following
Hardten, MDb,c, Benjamin J. Fogal, OD: laser vision correction (an American
Enhancing Intraocular Lens Outcome wavefront aberrometer in eyes after Ophthalmological Society thesis). Trans
Precision: An Evaluation of Axial Am Ophthalmol Soc. 2013;111:34‒45.
Length Determinations, Keratometry, refractive surgery. J Refract Surg. 35. Tang M, Li Y, Huang D. An intraocular
and IOL Formulas, Ophthalmol Clin N 2013;29:484‒489. lens power calculation formula based
Am 19 (2006) 435–448. 28. Aramberri J. Intraocular lens power on optical coherence tomography:
23. Abulafia A, Hill WE, Koch DD, et al. a pilot study. J Refract Surg. 2010;
Accuracy of the Barrett True-K formula calculation after corneal refractive 26:430‒437.
for intraocular lens power prediction 36. Wang L, Booth MA, Koch DD.
after laser in situ keratomileusis surgery: double-K method. J Cataract Comparison of intraocular lens power
or photorefractive keratectomy for Refract Surg. 2003;29:2063‒2068. calculation methods in eyes that have
myopia. J Cataract Refract Surg. 29. Haigis W. Intraocular lens calculation undergone LASIK. Ophthalmology.
2016;42:363‒369. 2004;111:1825‒1831.
24. Yang R, Yeh A, George MR, et al. after refractive surgery for myopia:
Comparison of intraocular lens power Correspondence to:
calculation methods after myopic laser Haigis-L formula. J Cataract Refract Dr. Sandhya Makhija
refractive surgery without previous Surg. 2008;34:1658‒1663. Department of Ophthalmology,
refractive surgery data. J Cataract 30. Shammas HJ, Shammas MC, Garabet Sant Parmanand Hospital, Delhi, India
Refract Surg. 2013;39:1327‒1335.
25. Wang L, Hill WE, Koch DD. Evaluation A, et al. Correcting the corneal power
of intraocular lens power prediction
methods using the American Society of measurements for intraocular lens
Cataract and Refractive Surgeons post-
keratorefractive intraocular lens power power calculations after myopic laser in
calculator. J Cataract Refract Surg.
2010;36:1466‒1473. situ keratomileusis. Am J Ophthalmol.
26. DeMill DL, Moshirfar M, Neuffer MC, 2003;136:426‒432.
et al. A comparison of the American 31. Hamed AM, Wang L, Misra M, et al. A
Society of Cataract and Refractive comparative analysis of five methods
Surgery post-myopic LASIK/PRK of determining corneal refractive
intraocular lens (IOL) calculator and
power in eyes that have undergone

myopic laser in situ keratomileusis.
Ophthalmology. 2002;109: 651‒658.
32. Holladay JT, Hill WE, Steinmueller A.

Corneal power measurements using
Scheimpflug imaging in eyes with prior
corneal refractive surgery. J Refract
Surg. 2009;25:862‒868.
33. Tang M, Wang L, Koch DD, et al.

Intraocular lens power calculation after

previous myopic laser vision correction

based on corneal power measured

Makhija S. et al. IOL Calculation Formulas: A Major Review www. dosonline.org 51

Review Article

Cataract Surgery-Evolution through Ages

Dr. Prateeksha Sharma MS, DNB, Dr. Shantanu Kumar MS, DNB, Dr. Varun Saini MS,
Dr. J.L. Goyal MD, DNB, Dr. U.K. RAINA MD, FRCS

Guru Nanak Eye Centre, Maharaja Ranjit Singh Marg, New Delhi, India.

Abstract: Amazingly, we as a society take science and technology for granted. We are blessed to have painless and guaranteed results of
medicine in this age. This article will describe history of cataract surgery from crude shaky methods in the beginning to the meticulous
safe technology in today’s world.

Crystalline lens in normal eye is a clear structure COUCHING dating to fifth century BC. It is derived from French
suspended by zonular fibres in natural position. It has a capsule, word “COUCHER” meaning to put to bed. Catarct was not
lens epithelium, cortex and nucleus which all together function removed from eye instead it was purposefully dislodged out
to focus clear image on retina and providing accommodation. of visual axis with a needle. This led to clearing of visual axis
Word Cataract means opacity of the lens. It also means a with instantaneous improvement in vision. An ancient Indian
torrent of water which is derived from Greek word υπόχυσις surgeon, Maharshi Sushruta ,first described the couching
(kataraktes).In Latin it is called suffusion which means an procedure in “Sushruta Samhita,Uttar Tantra”, (Figure 1) an
extravasation and coagulation of humors behind the iris. Arabs Indian medical treatise (800 B.C)5,6. Later eye was soaked with
called it white water1,2. Cataract which causes visual impairment warm clarified butter and bandaged.Sushruta cautioned that
has multifactorial causation of which ageing is most common3. this procedure should only be performed when absolutely
In today’s world visually significant cataract means visual necessary (Figure 2).
acuity of 20/40 or worse4. While in older times mature and
advanced cataract with near blindness vision was considered Later retained cataractous lens and lack of aseptic
visually significant. With advancements in surgical techniques, conditions led to deleterious effects on patients leading to
improvement in safety profiles, the threshold for cataract blindness shortly after the procedure. Throughout the history,
surgery has shifted to much earlier stage of development. oldest documentation of cataract is found in statue of 5th
dynasty (2457-2467 B.C) contained in the Egyptian Museum in
Cataract surgery which is performed worldwide is Cairo1 (Figure 3).
considered as one of the most common and oldest procedure.
There is evolution of cataract surgery as well as intraocular lens In the tomb of master builder Ipwy at Thebes (1200 B.C.)
replacement technology. It started with couching to modern shows an oculist treating the eye of a craftsman (Figure 4).
phacoemulsification with foldable lens replacement. Seeing the length of instrument it is interpreted as couching of
lens into the vitreous cavity.
COUCHING
A series of surgical instruments including needles carved
The oldest method to treat the mature cataract is on stone are seen in the temple of Kom Ombo constructed by
Tutmes III (1479-1425 B.C.) (Figure 5)

(1) (2) (3)

Figure 1: Sushruta Samhita, Uttar Tantra, an Indian medical treatise (800 B.C.). Figure 2: Maharshi Sushruta performing couching procedure.
Figure 3: Cheikh el-Beled statue with detailed white pupillary reflex in the left eye indicating a mature cataract ((taken from J Cataract Refract Surg
2001; 27(11):1714-5).

52 DOS Times - March-April 2019 Prateeksha S. et al. Cataract Surgery-Evolution through Ages

(4) (5) Review Article
(6)

Figure 4: Wall painting in the tomb of the master builder Ipwy at Thebes. Couching by oculist. (Modern copy of the painting at the entrance to
the Cornea Bank at Ain Sham´s University Hospital, Cairo, Egypt). Figure 5: Detail from the relief on the internal facade of the second wall in the
temple of Kom Ombo, Egypt. Figure 6: A series of cooper needles from the tomb of King Khasekhemwy at Abydos, Egypt (c. 2700 B.C.). (Courtesy
by National Museums Liverpool, England).

(7) (8) (9)

Figure 7: Aulus Cornelium Celsus. Figure 8: The French ophthalmologist Jacques Daviel (1696–1762) performed the first extra capsular cataract
extraction on April 8, 1747. Figure 9: John Taylor.

In the tomb of King Khaesekhemswy to its infectivity, dangerous nature and the modern era in cataract surgery. Daviel
(2700 B.C), Flinder petries found complications like blindness it is no more was staff of Hospital d’ Invalides and
few cooper needles having neither used in today’s world. became oculist to Louis XV after earning
hooks nor eyes in 1900, in the Royal his medical degree from the Medical
Necropolis at Abydos, Upper Egypt7. CATARACT EXTRACTION SURGERY School of Rousen. Although cataract
These are now preserved at National extraction gave good competition to
MuseumLiverpool,England (Figure 6). During 2nd century A.C. bronze couching but none of the two techniques
oral suction instruments that have been was free of complications which is proved
Couching was the procedure of unearthed seem to have been used for by the death of famous German composer
choice through thousands of years due to cataract extraction. Muhammad ibn Johann Sebastian Bach (1685-1750) and
simplicity of technique. In 1748 French Zakariya al-Razi, percian physician George Frrideric Handel (1685-1759)
doctor Daviel performed the first known described this procedure by 10th both of them underwent couching by
cataract extraction8. Greek travellers century who attributed it to Antyllus, British surgeon John Taylor (Figure 9)
brought this method from India and the a 2nd century Greek physician. The and were reported to be blind during last
Middle East9. Removal of cataract was procedure “required a large incision in years of life.
introduced in China from India via Silk the eye, a hollow needle, and an assistant
Road during the late West Han Dynasty with an extraordinary lung capacity”11. John Taylor was self-proclaimed
(206 B.C- 9 A.C.)10. It was known as jin pi Jacques Davie (1696-1762), the French personal eye surgeon to King George II,
shu in Mandarin. The work of the Latin ophthalmologist performed first extra the Pope and royal European families
encyclopaedist Aulus Cornelium Celsus capsular cataract extraction on April 8; who performed removal of cataract
(Figure 7) in De Medicinae shows the first 1747. He was first modern European by breaking them up into pieces. He
references to cataract and its treatment in physician (Figure 8). used to travel throughout the Europe
the West (29 B.C.)9. with coach painted with images of eyes
It was a revolutionary step in and use to deliver long, self-promoting
Couching is still used in some parts cataract surgery since the couching was speech in unusual oratorical style before
of Africa and Yemen.11However due invented which marked the beginning of

Prateeksha S. et al. Cataract Surgery-Evolution through Ages www. dosonline.org 53

Review Article (11) (12) (13)
(10)

Figure 10: Monument to the memory of the great German ophthalmologist Albrecht von Graefe, which can be admired on the Charité-Medical
University terrain (Berlin). Figure 11: Sir Nicholas Harold Lloyd Ridley. Figure 12: Peter Choyce. Figure 13: Charles D. Kelman, Father of
phacoemulsification.

performing surgery. lens implanted at the Wills Eye Hospital infrared) wavelength light. Collateral
Albrech von Graefe (1828-1870) in Philadelphia.Ridley worked hard to damage to surrounding tissues is
overcome complications and had refined restricted by focused ultrashort pulses
presided and dominated over the the technique by late 1960s.Peter Choyce (10-15 seconds). Heat production is less
entire 3rd International Congress of ,pupil of Harold Ridley developed several compared to neo dymium: YAG lasers. It
Ophthalmology, Paris 1867 (Figure 10). models of IOLs (Figure 11). acts by mechanism of photodisruption.
Photodisruption refers to the process of
His major contributions were The Choyce Mark IX, manufactured converting laser energy into mechanical
modifies linear extraction of cataract, by Rayner Intraocular Lenses, became the energy. Plasma formation occurs after
von Graefe sign in exophthalmic goitre, first US Food and Drug Administration- absorption of femtosecond laser energy in
von Graefe extraction Knife. Best was approved IOL in 1981. Introduction of the tissue. Cavitation bubbles are formed
the Ophthalmoscope through which intraocular lens changed the practice by rapidly expanding ionized molecules
Ophthalmology developed to greater of Ophthalmology providing superior and free electrons in the plasma. This is
height. He died at the age of 42. visual rehabilitation to over 14 million used to dissect tissue on microscopic scale.
individuals worldwide annually .The It focuses light of 3um spot size within in
INTRAOCULAR LENS last half –decade of the 20th century has 5um in the anterior segment.There are
been thus termed as the Golden Age of four commercially available platforms for
Sir Nicholas Harold Lloyd Ridley Ophthalmology and visual sciences. cataract surgery: Catalys (Optimedica),
(1906, Kibworth Harcourt, Leicestershire Lensx (Alcon Laboratories,Inc.), Lensar
– 2001, Salisbury, Wiltshire) worked as PHACOEMULSIFICATION (Lensar, Inc.), Victus (Technolas). First
an Ophthalmologist at Moorefield Eye step of procedure includes Docking
Hospital and St Thomas’ Hospital in After inspiration from dentist’s which may be of contact (applanating)
London (Figure 11). ultrasound probe Charles D.Kelman and non contact (non applanating) type.
(1930, Brooklyn, New York -2004, Boca Contact type have smaller diameter thus
Dissatisfied with blindness following Raton, Florida) introduced modern fit in smaller orbit. Non contact type
cataract extraction especially in children phacoemulsification technique in 1967 have advantage of less rise in intraocular
he invented first artificial intraocular (Figure 13). pressure.After docking is imaging which
lens in.Lack of inflammatory response is done by spectral-domain optical
to glass and plastic intraocular foreign It utilised ultrasonic waves to coherence tomography or ray–tracing
bodies in Royal Air Force Pilots who emulsify the nucleus of catarcatous reconstruction confocal structural
survived aerial combats inspired Ridley to lens in order to remove it from small illumination. Centration is very important
choose polymethylmethacrylate ( PMMA) incision thus reducing the extended stay for imaging. After imaging laser treatment
as lens material12. Introduction of the at hospital. It also made the surgery is given for 3 to 30 seconds during which
implanatable intraocular lens permitted painless. After doing his residency (1956- capsulorhexis is performed first followed
more efficient and comfortable visual 1960 (at wills Eye Hospital Philadelphia, by lens fragmentation and wound
rehabilitation after cataract surgery in Dr kelman worked as an ophthalmologist creation. Although good visual and optical
1940s.Ridley implanted first successful at the Manhattan Eye ,Ear and Throat quality outcomes have been reported but
IOL at St. Thomas’ Hospital London. It was Hospital in New York. the differences between femtosecond
manufactured by the Rayner Company of laser-assisted cataract surgery and
Brighton and Hove, East Sussex (Spalton, FEMTOSECOND LASER conventional surgery are not statistically
2009). But this did not gain much TECHNOLOGY significant. Capsulorhexis made by femto
popularity due to many adverse.His paper is highly reproducible,uniform,centered
on “Intra-Ocular Acrylic Lenses” at Oxford Femtosecond laser is a new and precise compared to manual rhexis.
Ophthalmological Congress met with technology introduced in ophthalmology But the procedural cost and multiple
significant opposition from professional in 2001. It was initially developed steps needed for femto outside the
colleagues. It was also condemned at as a tool to create lamellar flaps in
American Academy meeting in Chicago. In situ keratomileusis (LASIK) ,recently
1952 the first IOL implant was performed defined for use in cataract surgery. It
in the United States, a Ridley-Rayner uses Neodymium glass 1053 nm (near-

54 DOS Times - March-April 2019 Prateeksha S. et al. Cataract Surgery-Evolution through Ages

Review Article

surgical table hinders the popularity of development of the intraocular lenses Dynasty. London.
the technology. Few reports have been and phacoemulsification have made 8. Floyd RP. (1994). History of cataract
published emphasising the increased it easier, safer and more satisfying.
rate of anterior capsular tear rate and These procedures can be performed surgery. In: Principles and practice
rough edges of capsulotomy on scanning in early cataracts when they are soft of Ophthalmology. Vol. I, Albert DM,
electron microscopy as compared to unlike couching which was done Jakobiec FA. pp. 606-608. W.B. Saunders
manual capsulorhexis. on mature cataracts. Also these Company. Philadelphia.
have low complication rates with 9. Wales J. Cataract surgery. (accessed 4
ZEPTO PRECISION PULSE shorter convalescent period. Vision is Nov 2010), Available from: <http://
CAPSULOTOMY restored with customised intraocular en.wikipedia.org/wiki/Cataract_
lenses. Viscoelastic agents have been surgery>
Zepto is the trade name of developed synchronously with modern 10. Lade A, Svoboda R. (2000). Chinese
technology called Precision pulse phacoemulsification techniques, playing Medicine and Ayurveda. Motilal
capsulotomy (PPC) developed by an integral role in the success of this new Banarsidass. McGrath D. Couching’ for
Mynosys (Fremont, California) which is technology. cataracts remains a persistent problem
a noval capsulotomy method. It consist in Yemen. EuroTimes, September 2005,
of a disposable handpiece and nano REFERENCES p. 11.
engineered capsulotomy tip powered by 11. Savage-Smith E (2000). The Practice
a small console. Tip has a circular nitinol 1. Ascaso FJ, Cristóbal JA. (2001). The of Surgery in Islamic Lands: Myth and
ring covered with silicon cup which can Oldest Cataract in the Nile Valley. J Reality. Soc Hist Med, 13 (2): 307-321.
be inserted through 2.2 mm of corneal Cataract Refract Surg, 27:1714-1715. 12. Williams HP. (2001).. Sir Harold
incision.Ater positioning the ring on Ridley´s vision. Br J Ophthalmol,
anterior capsule small amount of suction 2. Cristóbal JA, Ascaso FJ. (2007). Historia 85:1022-1023.
is applied through external console. A de la Cirugía de la Catarata. In:. El
rapid series of electrical pulses totalling Libro del Cristalino de las Américas, Correspondence to:
4ms is used to creat capsulotomy. Centurión V, Nicoli C, Villar-Kuri J, pp. Dr. Prateeksha Sharma
It simultaneously cuts all 360o of the 25-37. Livraria Santos Editora. Sao Guru Nanak Eye Centre,
apposed surface without cauterizing Paulo. Maharaja Ranjit Singh Marg,
it.Short duration of energy and silicon New Delhi, India
cover of the ring prevents collateral tissue 3. Petrash JM. Aging and age-related
damage. Zepto is 1 million times smaller diseases of the ocular lens and vitreous
than femto. Both the small size of the body. Invest Ophthalmol Vis Sci.
instrument and the several millisecond 2013;54:ORSF54-ORSF59.
speed of capsulotomy creation inspired
this name. 4. Pascolini D, Mariotti SP. Global
estimates of visual impairment: 2010.
CONCLUSION Br J Ophthalmol. 2012;96 (5):614-618.

Although cataract surgery started 5. Duke-Elder S. (1969). “Sushruta
long back in historical age but the Samhita-Uttar Tantra”, chap. 17, verses
57-70. In: System of Ophthalmology.
Duke-Elder S. Vol. II, pp. 249.

6. Chan CC. (2010). Couching for cataract
in China. Surv Ophthalmol, 55(4):393-8

7. Petrie WMF, Griffith FL. (1900). Sold
at the Offices of the Egypt Exploration
Fund. The Royal Tombs of the First

Prateeksha S. et al. Cataract Surgery-Evolution through Ages www. dosonline.org 55

Perspective

Keeping the Hope Alive - Building A
Tertiary Eye Centre

Dr. Arvind Kumar Morya, Dr. Anushree Naidu, Dr. Sonalika Gogia, Dr. Sujeet Prakash, Dr. Sulabh Sahu
Department of Ophthalmology, All India Institute of Medical Sciences, Jodhpur, India

“A small seed in high spirit becomes a plant and that plant with courage and determination turns into a Giant Tree to serve
many lives almost to the eternity “ -AKM

AComprehensive tertiary eye care centre Glaucoma, Medical Retina, Paediatric Ophthalmology and some
providing quality eye care services to all the of the extra ocular procedures. From scratch to the current
population including the underprivileged ones scenario, too far away from reaching our goals this journey has
is a far-off dream that we saw. Although there been a great learning experience.
are quite a few world class centres in India
providing best of the facilities, there is major Development of a tertiary eye care centre is no cinch.
lacuna in demand supply relationship. Moreover, majority of Following are some of the practices that we incorporated in our
the population in India belongs to rural and suburban areas, institution:
in which places providing latest facilities is far from reality.
There is a lack of well-trained surgeons, infrastructure building 1. Acquiring trust of the patients: It requires a great deal
and maintenance and awareness to reach out to the available of perseverance to build an eye care system which is trusted by
facilities the patients. This trust can be achieved only through personal
interaction with the patients. Many a times it is forgotten that
India, the second most populous and the seventh largest what we are treating is a patient not a disease. Small amount
country in the world; a country where every year 3.8 million of empathy is what is required sometimes in building trust. A
people turn blind as a consequence of cataract; a country with system which is trusted by the patients can create wonders.
ratio of 1 Ophthalmologist for ~90000 population, a country
where 65% of surgeries are performed in private sector with 2. Triage of patients: Whilst many a times, in a busy
50% of Ophthalmologists being surgically inactive; a country OPD patients requiring special attention are overlooked, it
which houses 15-18.6 million blind people. The unmet need of is important to ensure triage. The patients with chronic or
acceptably trained surgeons in the country is no clandestine. severe illnesses that require more patient compliance for the
management of their illnesses eg patients of glaucoma need
Above scenario depicts the plight of the rural and the more attention, more counselling and more amount of patient
underprivileged population in India in need of quality eye care care. We have developed a three tier system of counselling
services. Majority of this population is unable to reach out to wherein the patients are being counselled by the optometrist,
the available facilities and if so, often there is much delay in the resident doctors and treating consultant. This helps in
seeking the health care. The result is, many of the patients fall picking up patients requiring proper attention and then
prey to diseases, that could otherwise have been cured. Many providing them with adequate information.
eyes lost, skilled manpower lost, it creates a social as well as
economical burden to the society. 3. Audio-visual aids: We have incorporated audio-visual
system as an integral part of our counselling. This provides
Rationale: About 22% of India’s population belongs to the patient with better insight to the disease process as well as
category of below poverty line. The right to high quality eye the management of the same. The audio-visual aids are being
care for this under-privileged population can be served only used for individual counselling of the patients as well as a
by providing them with a self-sufficient tertiary eye care centre public awareness tools. Information regarding common ocular
in government sector. There are only few such centres in India problems is being displayed on daily basis on television screens
proving comprehensive eye care facility to its underprivileged in front of OPD.
population.
4. Initiation of Post graduate course: Post graduate
The availability of a tertiary eye-care centre in tier two students form an integral part of the work force of the
city of India is the need of the hour. Our aim was to build a Department. Initiation of Post graduate courses add to the
self-sufficient tertiary eye care centre in a government set up integral manpower of the department. Once trained they form
that could provide basic as well as quality eye care services to the skill full workforce of the Department. Initiation of these
the population. In an institute that is in its developing phase, courses adds to the quality care to the patients.
we have tried to build a centre that could provide facilities in
multiple sub-specialities like Cataract and Refractive, Squint, 5. Employment of sub-speciality trained Senior
Residents: Employment of sub-speciality trained senior
residents can if not substitute but aid to the quality of eye care

56 DOS Times - March-April 2019 Bhalla J.S. et al. Capsulotomy for Cataract Surgery- Evolution of A Journey

Perspective

services that would have been otherwise need to be identified as training centres community level such as promoting
possible only in a well Developed eye which can provide productive training to eye health in the community, screening,
centre with Sub -speciality Units. budding ophthalmologists. Infrastructure case finding and referral, emergency
development would include the provision treatment, identifying and referring for
6. Running of multiple sub- of good quality surgical microscopes, A rehabilitation those who are already
specialities with a small work force: scan machines, ultrasound machines, blind, and providing commonly required
A comprehensive Ophthalmologist can YAG laser machines which would make services like refractive error correction.
provide care to multitude of patients the post graduate training worthwhile Depending on the services rendered,
which is of utmost importance for a and productive. Camps in outreach areas the provider of primary eye care could
developing centre by organizing weekly can be arranged in association with range from a general primary health
Speciality Clinics. a tertiary care hospital which would worker to a well-trained ophthalmic
ensure that cataract surgeries happen in technician. The vision centres are staffed
7. Short term Fellowships for the hospital settings, clearly bringing an end by vision technicians–paramedics trained
Consultants: Anterior segment surgeons to surgeries in poorly equipped operation in ophthalmic evaluation, refraction,
can be trained in multiple sub – speciality theatres at camp sites and keeping dispensing spectacles, and diagnosing
by opting for short term fellowships (2/3 chances of Infections to a minimum level. potentially blinding conditions.
monthly) annually during off-season This would quadruple the number of
on alternate basis without hampering cataract surgeries performed on a daily Secondary-level eye care is provided
routine work. basis, ultimately reducing the burden of by ophthalmologists and covers
preventable blindness. comprehensive ocular examination,
8. Developing neglected sub- cataract surgery, simple glaucoma
specialities: In the present time most of Investing in human resource surgery, minor procedures, nonsurgical
the Ophthalmologists are interested in development in the field of Ophthalmology management of other conditions, and
Cataract surgeries only so practice can would yield great results. Ophthalmology referral to tertiary care for cases that
be made more meaningful and impact residency program has to improve require the attention of subspecialists
causing sub-specialities like Paediatric tremendously. The importance of para- in ophthalmology and more advanced
–Ophthalmology, Medical – Retina, Dry clinical staff- Optometrists, counsellors, facilities.
Eyes and Refractive services. lab technicians needs to be emphasised. A
global exercise to review the distribution Tertiary eye care centres are staffed
What needs to be done? of practicing ophthalmologists showed bysubspecialistsandhavethecapability to
that there is a wide gap between the need provide the complete spectrum of eye care
Setting up refraction services at and the existing human resource both in services like paediatrics ophthalmology,
Primary Health centres, setting up a high and low income countries. retinal clinic, cornea clinic, glaucoma
separate ward in district eye hospitals clinic, oculoplasty, etc. Ophthalmologists
and dedicated ophthalmic theatres. Optometrist to ophthalmologist ratio are generally categorized as ophthalmic
Regional institutes of ophthalmology should be optimum, which would ensure surgeons and medical ophthalmologists,
and selective medical colleges should that the ophthalmologist engages himself depending on their job responsibilities.
be developed into centres of excellence. in more clinical work and surgeries Medical ophthalmologists (also termed
Substantial funds should be provided and the basic work is taken up by the specialist ophthalmologists) could
to Centres capable of developing in RIO supporting staff. Formal and recognised support consultant ophthalmologists
and teaching hospitals for upgradation courses in optometry should be started to in comprehensive eye assessment
through purchase of capital equipment. accredit the training in this cadre and to (basic work up) and medical treatment
Capital grants could also be given to select stipulate standards. of chronic, age-related diseases such
voluntary eye hospitals in the NGO sector as diabetic retinopathy, glaucoma,
to enhance their own infrastructure Overall a strong foundation has to dry eye syndrome, etc., Consultant
capacity. A significant volume of be laid for eye care. Primary eye care ophthalmologists, thus, could focus
eye care in India is provided by the still holds the key to universal coverage. on surgical management of avoidable
voluntary sectors. Vision 2020 provides However there is a need for well- blinding eye diseases. Thus, future
a platform for all non-governmental developed tertiary care centres which evaluation of manpower for eye care
organisations to come together. This will can provide comprehensive care, provide should gather information on medical
increase the effectiveness of advocacy, training and engage in research. ophthalmologists and ophthalmic
influencing policy and promoting surgeons to ensure a rational distribution
best practices. Strong voluntary care The six main foundations of a health of both subgroups. To meet the growing
would also require a strong public- system are: human resources, finance, need for tertiary services, we have had to
private partnership. Government setup health information, governance, services closely monitor the patient volumes per
would ensure significant volume in the delivery and consumables and technology. specialist and enhance their numbers,
delivery of eye care and private sector While not all eye conditions require as well as the facility, through advance
involvement would ensure reduction in the most advanced treatment facilities, planning. In addition, tertiary eye care
cost of treatment. Also public private neither can all eye care be addressed by system can have a cloud-based platform
partnership would ensure staffing and facilities lacking tertiary care expertise for remote screening of fundus images
upkeep of the infrastructure. Planning and equipment. The concept of primary, for diabetic retinopathy. Such proactive
and execution would be strengthened by secondary, and tertiary levels of care is reach into the communities including eye
the participation of all stakeholders. needed for providing the appropriate camps and serving these communities
management of the patients. will result in overall increase of patients
Another important aspect of capacity
building is enhancing surgical skills Primary eye care would include
through training. A number of Institutions services or activities carried out at

Bhalla J.S. et al. Capsulotomy for Cataract Surgery- Evolution of A Journey www. dos-times.org 57

Perspective

who directly access the tertiary hospitals to understand the mechanism at the place for training ophthalmologists, as
and has served to further increase the genome, transcriptome and proteome well as other eye care personnel, which
demand for subspecialty services as level. It is possible that the outcome of constitutes one of the several advantages
well as the numbers of paying clientele. the research could be translated back to of creating such institutions where
The distance patients travelled to obtain the patients in the clinic in terms of early they are needed. This expenditure has
services according to the subspecialty diagnosis or a drug target and how it will not increased despite an increase in
type, as a surrogate for demand for be helpful in a better understanding of population. Hence, optimum utilization
services. In addition to reflecting very disease process and improvement in the of available resources and improved
substantial demand for tertiary services, treatment methods to attain the goals of performance are essential to reach the
such a large proportion of long-range Vision 2020. short-term national health objectives.
travellers will require adjustments to On one side, they are in the process
scheduling patterns, and may require Research can dramatically improve of developing high quality human
plans to facilitate overnight stays for the work of mid-level eye health resources; and on the other side, they
patients and accompanying persons. In personnel who want to provide the best have to address avoidable blindness due
tertiary eye care institute we can tie up possible care based on accurate and to eye diseases on urgent basis in order
from the available local NGOs and sub relevant evidence. This hierarchical to mitigate a substantial backlog. To
specialist for providing the required care approach has been widely advocated over some extent, this could be addressed by
for the patient management, this kind the last decade since the launch of the hiring trained allied eye care personnel.
of care has been successfully applied in global initiative VISION 2020 the Right Additionally, experts could manage
premiere eye care institute in our country to Sight, as a valuable design for eye care blinding eye diseases at state of the art
like LV Prasad, Narayana Nethralaya, infrastructure. institutions.
Arvind eye care institute, etc . A tertiary
centre approach also provides the Tertiary-level centres also offer When designed and executed
opportunity for a fertile interaction of training for the budding ophthalmologist, properly, this hierarchy in services can
specialists across the watershed areas post graduate courses and training ensure both timely and cost-effective
between disciplines, which may lead to courses for optometrists and technicians treatment, and provides a paradigm
bettering of focused, disease-specific handling the ophthalmological intended to ensure that the investments
programs. equipments. Increasingly, day care in infrastructure, equipment, and eye
surgeries and short hospital stays are care personnel are utilized optimally at
While the secondary-level have preferred. The diagnostic and treatment all levels.
centre been common and primary eye modalities have also become more
care centres are being set up to reach the sophisticated and less invasive. These A long journey passed by and a long
unreached, setting up tertiary care centres technologies need to be handled by journey to reach the destination, we
has been less aggressively pursued, as it trained assistants, technicians, and hope that this dream will sure turn into
requires more investment and trained optometrists. Hence, more support staff reality so long live a hope to excel to serve
staff, and there have been uncertainties is required. Tertiary care services require humanity optimally. Turn dreams into
about the potential demand for such highly trained staffers (ophthalmologists reality.
services. Over time, with increasing and support staff), in whom an institution
affluence and improved health care, makes a large investment. Similar to Correspondence to:
resources could be channelled elsewhere other professionals, ophthalmologists Dr. Arvind Kumar Morya
towards developing other goals. One generally seek opportunities for growth. Department of Ophthalmology,
such development is the emergence of Keeping them engaged in a limited set of All India Institute of Medical Sciences,
ophthalmic research. The combination of basic services can become monotonous Jodhpur, India
high clinical load, extensive community over a period of time, and may lead to
participation, and access to a large losses of highly desirable personnel.
network of eye hospitals provides ideal Providing ongoing training to them in the
opportunities for conducting clinical, latest technologies, as well as providing
laboratory, population-based studies and the opportunity for sub-specialization,
social and health systems research. is therefore important for retention as
well as for providing the best quality of
The basic research carried out services. Tertiary centres are an ideal

58 DOS Times - March-April 2019 Bhalla J.S. et al. Capsulotomy for Cataract Surgery- Evolution of A Journey