DJO Oct- Dec 2022 Vol 32 issue (2)

DJO Vol. 32, No. 2, October-December 2021

Case Report

Brow Revision Following Animal Bite:
A Case Report and Review of Literature

Anju Kochar, Shaheen Farooq

Department of Ophthalmology, SP Medical College, PBM and associated group of Hospital, Bikaner, Rajasthan, India.

Abstract Traumatic laceration caused by animal bite on face carries disfigurement effect and psychological trauma to
patient. Dog and cat bites being more common in children may involve periocular structure. Eyebrows being
one of the five aesthetic subunits of forehead and playing a key role in facial expression, needs due focus while
correcting such injuries. This article is aimed at presenting considerations regarding eyebrow reconstruction,
exemplified by a case report.

Delhi J Ophthalmol 2021; 32; 49-50; Doi http://dx.doi.org/10.7869/djo.716

Keywords: Animal Bite, Eyebrow Reconstruction

Introduction The misaligned margins of eyebrow were approximated

Animal attacks are common occurrences due to increased taking into account the normal contour of eyebrow with the

interaction between human and animals or due to aim of achieving continuous brow line. Interrupted sutures

encroachment of natural habitat of animals by humans. were applied with 6-0 vicryl in two layers and defect was

Dog and cat bite injuries are particularly more common in corrected (Figure 3).

children and are more likely to be on the face.1 Although This otherwise simple technique, gave excellent cosmesis
lips, nose and cheek comprises the central target area, with gratifying results.
periocular structures are also involved frequently in canine
bites (27%).2 These injuries can result in severe deformity Discussion

with inevitable physical, functional and psychological Eyebrows have linguistic and aesthetic function. It is one of

consequences.The philosophy regarding management the aesthetic subunits of forehead: central forehead, lateral

of these injuries has changed from healing by secondary forehead and the left and right eyebrow.3 Eyebrows are

intention to primary closure for getting optimized aesthetic shaped, tattooed; brow lift procedures are done to enhance

results but till date we still get several patients who incurred facial features. In such an era where aesthetic sense prevails,

animal bite in childhood and strive for cosmetic correction misaligned eyebrow may lead to loss of self-esteem. Both

of the disfigurement thereafter. position and continuity of eyebrow hairline play an important

Case Report role in the overall harmony of the face. Reconstruction of
this region is considered challenging but necessary. Despite
We report one such case of a 40-year old female, presenting

to tertiary centre. Although her chief complaint was

diminution of near vision, her emphasis was more on her

disfigured left eyebrow which was the result of a cat bite

at the age of 6 months. The wound was not attended by any

medical personnel: instead first aid was given at home. It

was allowed to heal by secondary intention leaving behind

not only an unsightly scar but also a slit in the left eyebrow

along with vertical misalignment of the two slit parts (Figure

1).

The vertical distance between cut ends of the eyebrow was Figure 2: Diagrammatic representation of the eyebrow defect and rhombus
1.5cm. Surgical correction involved making a rhombus shaped incision at the cut end.
shaped incision in between the cut ends of the eyebrow. The
skin and subcutaneous tissue were removed at the incision
site (Figure 2).

Figure 1: Preoperative photograph with misaligned eyebrow 49 Figure 3: Post operative photograph

E-ISSN: 2454-2784  P-ISSN: 0972-0200 Delhi Journal of Ophthalmology

DJO Vol. 32, No. 2, October-December 2021

their aesthetic and functional importance, there is limited Declaration
consensus as to which reconstructive technique is the best.4
Declaration of patient consent: The authors certify that they

We reviewed literature on eyebrow reconstruction using the have obtained all appropriate patient consent forms. In the
PubMed database and medical texts. The following search
terms were used: eyebrow reconstruction, eyebrow defects, form the patient(s) has/have given his/her/their consent for
eyebrow transplantation.
his/her/their images and other clinical information to be

reported in the journal. The patients understand that their

Aim of eyebrow reconstruction is to achieve: appropriate names and initials will not be published and due efforts will
shape, hair direction, and thickness; no complications
(recipient/donor alopecia, dis-figuration, notching/elevation/ be made to conceal their identity, but anonymity cannot be
ptosis);symmetry, dynamicity; minimal stages; closure
within the same cosmetic unit; horizontal and hidden guaranteed. References
incisionsand maximize conservation of hair follicles.5
Matsuo et al identified three main options for eyebrow 1. Kumar V, Pandey V, Tiwari P, Gangopadhyay AN, Sharma SP, Bedi
reconstruction: free hair transfer, free skin graft with hair RS. Animal bites in children: A developing country′s perspective.
transfer and flap transfer.6 Asian J Oral Health Allied Sci 2013;3:56-9.

Choice of reconstruction technique needs to be 2. Prendes, Mark A et al :Ocular Trauma From Dog Bites:
individualized according to extent and location of the defect, Characterization, Associations, and Treatment Patterns at a Regional
relationship to other structures,extensibility of residual skin, Level I Trauma Center Over 11 Years.Ophthalmic Plastic and
gender and age, state of donor and recipient sites. Various Reconstructive Surgery: July/August 2016 - Volume 32 - Issue 4 - p
algorithms have been designed for this purpose. Ridgway 279-283
et al presented a surgical algorithm for reconstruction of full
and partial eyebrow defects based on the etiology of defect. 3. Fattahi T: An overview of facial aesthetic units. J Oral MaxillofacSurg
Their idea was to reconstruct burn or radiation defects with 2003;61:1207–1211.
local flaps while in “no burn” patients, single follicle and
hair plug transplants were preferred.7 4. Edwin Figueira et al: Eyebrow reconstruction, Orbit, DOI:
10.1080/01676830.2017.1337171
Algorithm presented by Accord et al focused on eyebrow
defect size and position. Eyebrow defects were divided into 5. Gardner E, Goldberg LH. Eyebrow reconstruction with the
5 categories.Defects less than 1/5th size can be closed by subcutaneous island pedicle flap. DermatolSurg
2002; 28:921–925.
direct closure. Direct closure represented the simplest and
most effective corrective remedy for small defects.
6. Matsuo S, Hashimoto I, Seike T, et al.: Extended Hair-bearing Lateral
Orbital Flap for Simultaneous Reconstruction of Eyebrow and
Eyelid. PlastReconstrSurg 2014;2:e111

7. Ridgway EB, Pribaz JJ: The reconstruction of male hair-bearing facial
regions. PlastReconstrSurg 2011;127:131–141


8. Giuseppe Accardo et al: A Surgical Algorithm for Partial or Total
Eyebrow Flap Reconstruction. Journal of Surgical Oncology
2015;112:603–609 .

The incision lines were extended beyond the limits of the Cite This Article as: Anju Kochar, Shaheen Farooq. Brow
eyebrow in order to create a vertically oriented ellipse
ensuring that upper and lower margins of the eyebrow revision following animal bite: A Case Report and Review of
were joined together. In cases of larger defects, different
flaps were used sourced from the rich vascularization of the Literature: A Case Report and Review of Literature. 2021; 32 (2):
eyebrow area.8
49-50.

Acknowledgments: Nil

Conflict of interest: None declared
Source of Funding: None

Edwin et al in their review article stated that for smaller Date of Submission: 30 Mar 2021
defects, options include primary closure, advancement flaps, Date of Acceptance: 18 Aug 2021
and subcutaneous pedicle flaps. For large defects, an option
was to use a flap or graft if necessary, and recreate brow Address for correspondence
hair using follicular unit transplantation (FUT)/tattooing/
makeup. Alternatively, hair-bearing skin via regional flaps Anju Kochar,
or grafts can be recruited.
MS,Senior Professor
From direct closure of small defect to complicated grafting
Department of Ophthalmology,
for large defects,desired end result is always good aesthetic SP Medical College, PBM and
associated group of Hospital,
outcome. In our case, ther defect had already healed by Bikaner, Rajasthan, India.
Email: [email protected]
secondary intention there by leaving a scar with vertical

misalignment. Simple excision of scar tissue was done

by making a rhombic incision. It was closed by direct

closure by approximating both edges of slit eyebrow.

Conclusion

Eyebrow defects even small can be very distressing and due

focus should be given on its reconstruction to as normal

as possible. Direct closure of small defect is simple and Quick Response Code

gratifying.

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DJO Vol. 32, No. 2, October-December 2021

Case Report

Neuroretinitis and Covid19: An Astounding Correlation

Dhaivat Shah, Rahul Singh, Garima Vaishnav, Ravin Punamia

Department of Ophthalmology, Choithram Netralaya, Shriram Talawadi, Dhar Road, Indore Madhya Pradesh. India.

Abstract Neuroretinitis is an inflammatory condition characterized by optic disk edema and formation of a resultant macular star. It
can be autoimmune or caused by an infectious or post viral etiology. Looking at today’s scenario, COVID-19 is an important
health issue and has been declared as pandemic by the World Health Organization. Corona virus is capable of producing a
wide spectrum of ocular manifestations ranging from anterior segment pathologies like conjunctivitis and anterior uveitis to
sight-threatening conditions like retinitis and optic neuritis. In this case series, we present two cases which presented with
loss of vision and were diagnosed as neuroretinitis which later turned out to be COVID positive. Hence, a thorough ocular
and systemic examination, correct diagnosis along with strong suspicion for systemic involvement is the key to optimal
outcome in current era of pandemic.

Delhi J Ophthalmol 2021; 32; 51-54 Doi http://dx.doi.org/10.7869/djo.717
Keywords: Neuroretinitis; Covid-19; Disc Edema; Macular Star; OCT.

Introduction examination, the best corrected visual acuity (BCVA) was

Neuroretinitis is an inflammatory disorder of posterior 6/12 in both eyes. Ishihara color charting showed defective

segment of the eye presenting with optic disc edema and red-green vision. Except for early cataract, anterior segment

delayed development of a macular star. Usually, the patients was within normal limits. On fundus examination, right eye

present with an acute unilateral painless loss in vision. The showed blurring of disc margins, elevated fovea and early

causative factors described previously are viral infections and deposition of hard exudates in a radial manner over macula

idiopathic occurrences.1 No correlation has been mentioned (Figure 1a). Left eye also showed a similar picture, except

with the COVID19 infection till date. We herein describe two that the disc edema was relatively less (Figure 1c). The OCT

cases of neuroretinitis which on further investigation turned in right eye showed subretinal fluid extending from the

out to be COVID positive and eventually responded well to disc till fovea including peripapillary region along with few

treatment. hyper reflective spots at the outer plexiform layer correlating

Case 1 with the macular star appearance on fundus (Figure 1 b, d).

A 65 year old male walked into our hospital with complain On taking a detailed history, the patient reported mild
of decreased color vision in both eyes for 1 week. On headache at the time of onset of symptoms with on and off

Figures : 1 (1a) Fundus photograph of case 1 right eye showing, blurring of disc margins, elevated fovea and early deposition of hard exudates in a radial manner
over macula and a single superficial hemorrhage present supero-temporally. (1b) OCT of right eye of case 1 showing subretinal fluid extending from the disc till
the fovea along with hyper reflective spots seen at the outer plexiform layer correlating with the macular star appearance on fundus. (1c) Fundus photograph of
case 1 left eye showing, blurring of disc margins, elevated fovea and early deposition of hard exudates in a radial manner over macula relatively less as compared
to right eye. (1d) OCT of left eye of case 1 showing subretinal fluid over fovea extending from disc along with few hyper reflective spots seen at the outer plexiform

layer suggestive of macular scar.

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DJO Vol. 32, No. 2, October-December 2021

cough since a week. In conjunction with advice from in- slightly elevated with few hard exudates arranged in a starry
fashion (Figure 3a), and OCT confirmed subretinal fluid
house physician, MRI Brain and Orbit and COVID testing (Figure 3b). We sent the patient for a screening MRI brain
with orbit and a COVID test as the patient gave a history of
was ordered. For the neuroretinitis component, we started fever at onset. We also continued oral steroids (1mg/kg) in a
weekly tapering dose. The patient’s COVID test turned out
the patient on oral steroids in tapering doses and asked to be positive and was advised isolation. After one month
patients's vision improved to 6/9 with resolution of SRF and
him to review reports by teleconsultation. The patient was reduced exudates at macula(Figure 3c and 3d).

reviewed after 1 month, as the COVID test was be positive, Discussion

and he was kept under isolation for 2 weeks. A month later Neuroretinitis is an inflammation of neural retina and optic
nerve which was originally described by Leber in 1916 as
disc edema and fluid had decreased (Figure 2a, b) which "stellate maculopathy". This entity was restudied by Don Gass
in 1977, and he explained that disc edema precedes macular
was confirmed by OCT. Patient was symptomatically better exudates, and confirmed optic disc leakage by fluorescein
angiography and suggested the term "neuroretinitis."
with BCVA of 6/9 in both eyes. We tapered off oral steroids
Neuroretinitis is caused by inflammation of optic disc
eventually. Case 2 vasculature, which leads to exudation of fluid in the
peripapillary space. The trigger for this inflammation
A 22 year old male presented with blurry vision in right can be a viral infection, immunocompromised state or

eye since 10 days associated with mild headache and fever

which worsened over the next 4 days. The patient was

started on oral antibiotics and steroids by a local physician,

after which he reported improvement in vision and

systemic complaints. Present BCVA in right eye was 6/18

(previously documented 6/60 elsewhere) and left eye was

6/6. On fundus examination, right eye had a resolving disc

edema with a relatively clear neuroretinal rim. Macula was

Figures : 2 (2a) Fundus photograph of case 1 right eye post treatment, post treatment showing, resolving disc edema with deposition of peripapillary hard
exudates along with macular star. (2b) OCT of right eye of case 1 post treatment showing decrease in the subretinal fluid with numerous hyperreflective spots
in outer plexiform layer correlating with macular star and peripapillary exudates. (2c) Fundus photograph of case 1 left eye post treatment showing, resolving
disc edema elevated fovea and deposition of hard exudates in a radial manner over macula which are relatively less as compared to right eye. (2d) OCT of left
eye of case 1 post treatment showing decrease in subretinal fluid over fovea along with few hyper reflective spots seen at the outer plexiform layer suggestive of

macular scar suggestive of resolving disease entity.

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DJO Vol. 32, No. 2, October-December 2021

Figures : 3 (3a) Fundus photograph of case 2 right eye showing, resolving disc edema with relatively clear neuroretinal rim along with deposition of few
hard exudates in a circinate manner over macula with an elevated fovea. (3b) OCT of right eye of case 2 showing presence of subretinal fluid and numerous
hyperreflective spots suggestive of hard exudates in outer plexiform layer. (3c) Fundus photograph of case 2 right eye 1month post treatment showing resolved
disc edema with fairly clear neuroretinal rim along with deposition of hard exudates in circinate manner over macula. (3d) OCT of right eye of case 2 1month post

treatment showing minimal subretinal fluid with decrease in number of hard exudates in outer plexiform layer seen as hyperreflective spots.

idiopathic.2 Recent studies have shown that the COVID-19 exudative, filled with cellular debris, lipids and oxidative

(S) glycoprotein binds to the cell membrane protein components. The heavy elements like lipids cannot cross

angiotensin-converting enzyme 2 (ACE2) on its surface beyond the external limiting membrane (ELM). Thus, these

to enter human cells[3]. PCR analysis has revealed that exudates get deposited along the Outer plexiform (OPL) and

ACE2 is expressed mainly in the vascular endothelial cells Outer Nuclear Layers (ONL), which are clinically visible as

and arterial smooth muscle cells in various organs. During yellow deposits in a stellate fashion at the macula known

infection, the S protein is cleaved into subunits, S1 and S2. S1 as macular star. The transudative component can although

contains the receptor binding domain (RBD) which allows pass through the cellular junctions of the ELM and can

the virus to directly bind to the peptidase domain (PD) of accumulate beneath the subretinal space. This is seen

ACE2, while S2 helps in membrane fusion.3 clinically as a neurosensory detachment, and is commonly

The optic nerve is an extension of the brain tissue and thus has found in neuroretinitis.4

expression of ACE 2 receptors. The virus usually triggers an Diagnosis
autoimmune reaction once the membrane fusion takes place,
which can lead to release of antibodies and a neurovascular Clinical suspicion of the highest order is the key for diagnosis.
inflammatory reaction. The inflamed optic nerve head which Patients may be mildly symptomatic (mild decrease in vision,
is clinically seen as blurring of the neuroretinal rim margins defective color vision) or completely asymptomatic. All these
and disc edema is due to accumulation of fluid around cases should be examined after proper thermal screening
the disc and in peripapillary region. This fluid is mainly and sanitization: masks, shields and gloves are essential.

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DJO Vol. 32, No. 2, October-December 2021

An ophthalmologic examination should be performed given his/her/their consent for his/her/their images and
including visual acuity, intraocular pressure, color vision, other clinical information to be reported in the journal. The
automated visual fields or Amsler grid, pupillary evaluation patients understand that their names and initials will not
and a thorough fundus examination. Optic disc should be be published and due efforts will be made to conceal their
evaluated for edema, pallor, and vasculature for sheathing identity, but anonymity cannot be guaranteed.
or perivascular or splinter hemorrhage. Optical coherence
tomography (OCT) can help in visualizing fluid and References
exudates. Fluorescein angiography (FFA) may be performed
to assess for disc leakage or vascular pathology within the 1. Maitland CG, Miller NR. Neuroretinitis. Arch Ophthalmol.
macula or any non perfusion areas in the periphery. Other 1984;102:1146–50.
important points are time of onset, laterality, and duration
of symptoms. A history of similar episodes, recent travel, 2. Sundaram SV, Purvin VA, Kawasaki A. Recurrent idiopathic
contact with sick individuals, and sexual activity should be neuroretinitis: natural history and effect of treatment. Clin Exp
documented. A physician review to assess pulmonary status, Ophthalmol. 2010;38:591-596.
skin changes, cardiovascular issues, weight changes, and
constitutional symptoms should be sought. If neurological 3. Yuki K, Fujiogi M, Koutsogiannaki S. COVID-19
signs are evident, an MRI needs to be done. The MRI is pathophysiology: A review. Clin Immunol. 2020;215:108427.
usually normal in such cases except for contrasted enhanced
axial T1 weighted optic nerve head enhancement, which 4. Narayan SK, Kaliaperumal S, Srinivasan R. Neuroretinitis, a
would be expected in severe disc edema. Laboratory testing great mimicker. Ann Indian Acad Neurol. 2008;11(2):109-113.
should be guided by clinical suspicion and tailored to history
and physical examination. 5. Purvin VA. Optic neuropathies for the neurologist. Semin
Neurol. 2000;20:97–110.
Differential diagnosis for neuroretinitis includes
hypertensive retinopathy, papilledema, anterior ischemic 6. Franz Marie Cruz, Cheryl A. Arcinue. A Review Article on
optic neuropathy, diabetic papillopathy, disc and Neuroretinitis. Philipp J Ophthalmol 2018;43:3-9
juxtapapillary tumors and toxic etiologies.5
Cite This Article as: Dhaivat Shah, Rahul Singh, Garima
Management Vaishnav. Neuroretinitis and Covid19: An Astounding
Correlation Delhi J Ophthalmol 2021; 32 (2) 51 -54.
The disc edema in neuroretinitis is generally self limiting Acknowledgments: Nil
with excellent visual recovery in idiopathic cases. In around Conflict of interest: Nil
2-4 weeks the edema completely disappears, leaving residual Source of Funding: None
disc pallor occasionally. There are cases that have been Date of Submission: 14 Sep 2020
administered oral or high dose of intravenous pulse dose Date of Acceptance: 14 Oct 2020
of corticosteroids, with no concrete evidence regarding its
efficacy in improving the condition. Some physicians have Address for correspondence
also tried intravitreal steroids and Anti VEGF, with minimal Dhaivat Shah MS DNB
scientific evidence regarding its mechanism of action.6 All
patients with neuroretinitis with concurrent symptoms of Choithram Netralaya, Shriram
respiratory or gastrointestinal distress should be sent for Talawadi, Dhar Road, Indore
COVID testing. In cases where COVID test is positive, an Madhya Pradesh, India.
isolation of the patient and in-contact persons with adequate Email: [email protected]
monitoring measures is must. A consult with the physician
is important, so that medical treatment can be advised. The Quick Response Code
most dreaded complication is chronic visual loss due to
disc pallor, which is frequently seen in cases with recurrent
neuroretinitis.

Conclusion

Infections like Covid-19 trigger a strong immune reaction, for
which anti-inflammatory agents might be required. In our
cases, steroid therapy was already initiated by the primary
physician; hence we continued and tapered accordingly.
Otherwise, we believe the improvement in neuroretinitis is
due to the natural course of the disease, rather than due to
steroid therapy.

Declaration Of Patient Consent

The authors certify that they have obtained all appropriate
patient consent forms. In the form the patient(s) has/have

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DJO Vol. 32, No. 2, October-December 2021

Photo Essay

The Zonular Stripes

Prateek Jain, Pooja Sah, Anshuman Pattnaik
Department of Community Ophthalmology ,Global Hospital Institute of Ophthalmology, Abu Road, Sirohi, Rajasthan, India.

Long anterior zonules [LAZ] are zonules having anomalous anterior insertion on the lens capsule, thus reducing the size

of zonule-free zone. This article describes a diabetic elderly female who presented to us for cataract surgery. Examination

Abstract showed presence of bilateral persistent pupillary membrane [PPM] along with long anterior zonules. Association of PPM with
LAZ has been established in literature but bilateral PPM-LAZ association is a unique finding. The article also illustrates different

phenotypes of LAZ and their clinical associations. LAZ eyes have propensity for sight threatening diseases like glaucoma,

retinal diseases etc. Hence, a thorough ocular examination is warranted.

Delhi J Ophthalmol 2021;32;55-56; Doi http://dx.doi.org/10.7869/djo 718
Keywords: Long anterior zonules, Persistent pupillary membrane, Pigment dispersion, Hypermetropia, Abnormal zonular insertion.

Photo-essay

A sixty-five year-old diabetic female presented with
complaints of blurry vision. Best-corrected visual acuity was
6/36 OD and 6/24 OS Slit-lamp examination OU revealed
diffuse iris pigments on endothelium, persistent pupillary
membrane(PPM) and senile cataract. Dilated examination
showed radially-oriented annular-array of long anterior
zonules(LAZ)with scattered pigmentation in OU (Figure
1,2,3).

Figure 1: Slit-lamp images of OD(a) and OS(b) depicting PPM along with LAZ Figure 3: Magnified Slit-lamp image depicting annular-pattern of radially-
following mydriasis. oriented pigmented strings of LAZ reducing the zonule-free zone to <3mm.

Both eyes had normal intraocular pressure. Gonioscopy
revealed heavily pigmented open angles OU.Fundoscopy
showed signs of non-proliferative diabetic retinopathy with
healthy disc in OU. Eyes were hypermetropic with axial
length 22.60mm OD and 22.57mm OS.

She underwent phacoemulsification in OD.The continuous-
curvilinear-capsulorhexis was fashioned through LAZ with
inevitable stripping of zonules. Eventually, an optimum-
sized capsulorhexis was achieved (Figure 4).

Figure 2: Slit-lamp images a)Direct focal: Pigment dusting on endothelium Figure 4: Capsulorhexis challenge with LAZ : a) Rhexis is initiated, b) Rhexis
as well as on anterior lens capsule, b)Retro-illumination: The extension of extended radially(Yellow arrow) due to pull exerted by LAZ, c) Rhexis rescued
by Little’s manoeuvre(Green arrow), d) Completion of optimum sized rhexis
zonules towards pupil centre is noted.

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DJO Vol. 32, No. 2, October-December 2021

Insertion of zonules >1.5-2.0mm anterior to the equator Cite This Article as: Prateek Jain, Pooja Sah, Anshuman
of lens is termed as Abnormal Zonular Insertion(AZI) and Pattnaik The Zonular Stripes Delhi J Ophthalmology 2021, 32 (2):
such zonules are called long anterior zonules(LAZ). LAZ
are vestigial remnants of membrana capsulopupillaris as 55-56.
proposed by Bruckner.Vogt postulated them to be remnants Acknowledgments: The authors acknowledge the guidance
of tunica vasculosa lenti due to co-existing PPM. Roberts of Dr. V C Bhatnagar, Head of Department and Medical
found that LAZ eyes were 3.1 times more likely to have Superintendent, Global Hospital Institute of Ophthalmology.
PPM.1 Conflict of interest: None declared
Source of Funding: None
LAZ has two phenotypes.One phenotype in younger Date of Submission: 17 Nov 2020
population has been attributed to S163R mutation Date of Acceptance: 28 Jan 2021
in C1QTNF5 gene which causes Late-Onset Retinal
Degeneration (LORD). The other phenotype with unknown Address for correspondence
etiology is associated with age >50 years, female gender, Prateek Jain
hypermetropia and PPM.2
Department of Community
The contraction of anomalous zonules with forward rotation Ophthalmology ,Global Hospital
of ciliary body leads to angle closure glaucoma.1Also, rubbing Institute of Ophthalmology,
of LAZ with iris pigment epithelium causes presentation Abu Road, Sirohi, Rajasthan, India
similar to pigment dispersion syndrome(PDS).3,4 However, Email - [email protected]
PDS is prevalent in young myopic males whereas LAZ is
noted in elderly hyperopic females. Quick Response Code

Regarding ideal size of capsulorrhexis, some surgeons
advocate capsulorrhexis within zonule-free-zone whereas
others consider smaller capsulorrhexis a predisposing factor
for various complications.
LAZ serves as a surrogate marker for various sight-
threatening diseases. The occurrence of glaucoma in the
elderly and LORD in young patients must be ruled out.
Also,meticulous capsular management during capsulorhexis
is warranted.

References

1. Khurana M. Clinical Associations of Long Anterior
Zonules: A Review. PPCR [Internet]. 2015 Dec. 4 [cited
2021 Oct. 12];1(3). Available from: https://journal.ppcr.
org/index.php/ppcrjournal/article/view/23

2. Roberts DK, Newman TL, Roberts MF, Winters JE;
Long Anterior Lens Zonules and Intraocular Pressure,
Invest Ophthalmol Vis Sci. 2018 Apr, 59(5);2015-2023.
doi;10.1167/iovs.17-23705

3. Roberts DK, Winters JE, Castells DD;Pigmented striae
of anterior lens capsule and age-associated pigment
dispersion of variable degree in a group of older African-
Americans:an age,race and gender matched study,Int
Ophthalmol.2001;24(6):31322.

4. Newman TL,Roberts DK, Morettin CE, McMohan
JM,Roberts MF;Krukenberg’s Spindles Strongly Suggest
Long Anterior Zonule Associated Pigment Dispersion
Mechanism in Older Patients;Invest Ophthalmol Vis
Sci.2020 Jul 1;61(8):8

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DJO Vol. 32, No. 2, October-December 2021

Photo Essay

Multimodal Imaging in Diagnosis of Choroidal Metastasis in
Breast Carcinoma

Sriram Simakurthy, Madhu Kumar, Om Shankar, Ashok Kanakamedla, Jayamadhury Gudimetla, Anurag Shandil

Department of Ophthalmology, Sankara eye hospital, Pedakakani, Guntur, Andhra Pradesh India.

Intraocular metastasis is the most common malignancy of the eye in adults. It is commonly noted in uveal tract with choroid
being the most common site due to its high vascularity. Carcinoma breast is the most common primary malignancy that accounts
Abstract for choroidal metastasis in females and carcinoma of lung is the most common cause in males. In this article, we report a case of
54-year female who had carcinoma breast with choroidal metastasis in her left eye and highlight role of non-invasive multimodal
imaging viz Fundus Autofluorescence, enhanced depth optical coherence tomography and B scan in diagnosing the same.

Delhi J Ophthalmol 2021;32; 57-59; Doi http://dx.doi.org/10.7869/djo.719
Keywords: Choroidal Metastasis, Breast Carcinoma, Fundus Autofluorescence, Enhanced Depth -OCT

Case Description yellowish white sub-retinal lesions with adjacent exudative

A 54-year-old female presented with blurred vision in both retinal detachment was present in superotemporal quadrant
eyes for one-month duration. She had a history of carcinoma approaching the macula(Figure 1 b,c).

breast for which she underwent 11 cycles of chemotherapy. Fundus Autofluorescence (FAF) showed granular hypo-
At presentation, patient was off all chemotherapeutic agents. autofluorescent patches with adjacent hyper-autofluorescent
On examination, her best corrected visual acuity was 6/12 (Figure 1 e,f) area delineating the site of metastases in the left
in the right eye and 6/9 in the left eye. Anterior segment eye. Enhanced-depth imaging optical coherence tomography
examination showed NS 2 cataractous lens in both the eyes. (EDI-OCT) of left eye showed subretinal fluid at the
Relative afferent pupillary defect was not present in either posterior pole (Figure 2 a,b) and a choroidal elevation with
eye and intraocular pressure was 14 mmHg in both eyes. lumpy –bumpy contour of the retinal pigment epithelium,
Dilated fundus examination of right eye was completely compression of overlying choriocapillaries with overlying
normal (Figure 1a,d) however in left eye multiple foci of

Figure 1 : (a) Fundus photograph of right eye showing posterior pole. (b, c) Colour fundus photograph of left eye showing multiple yellow-white sub retinal lesions
with focal exudative retinal detachment. (d) Autofluorescence Right eye (TRC 50DX, Topcon, Japan) showing normal macular fluorescence (e, f) Autofluorescence

Left eye showing leopard spot pattern of mixed hyper and hypoautofluorescence

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DJO Vol. 32, No. 2, October-December 2021

subretinal fluid and hyper-reflective dots extending to outer hypo and hyper autofluorescence is known as “leopard
retina (Figure 2 c,d). spotting”.4

Ultrasound examination of LE showed a flat homogenous EDI-OCT shows choroidal elevation and choriocapillaries
hyper-reflective mass with high reflectivity with thickening compression with lumpy-bumpy contour of the retinal
of RCS complex in superotemporal quadrant with an pigment epithelial layer which is characteristically seen in
overlying uniform homogenous hypo-reflective space choroidal metastatic neoplasms. This is in contrast to nevus
suggestive of shallow sub retinal fluid (Figure 2 e,f). FAF and melanoma that usually show smooth, dome-shaped
and OCT examination of the right eye were within normal topography. Overlying the lesion, extensive subretinal
limits. fluid and a prominent line of shaggy photoreceptors is

Discussion

Figure 2 : (a,b) EDI-OCT via macula showing serous retinal detachment with shaggy photoreceptors (c,d) EDI-OCT via site of choroidal metastasis showing
choroidal elevation with compression of choriocapillaris, lumpy bumpy RPE, disruption of ORL at the site of choroidal mass lesion, and intraretinal speckles.

(e, f) B Scan showing a flat homogenous hyper-reflective mass with high reflectivity with thickening of RCS complex in superotemporal quadrant with an overlying
uniform homogenous hypo-reflective space suggestive of shallow sub retinal fluid.

The most common intraocular malignancy in adults is seen. Speckles (i.e., shed photoreceptor outer segments or
choroidal metastasis. The incidence of ocular metastasis pigment clumps within the sub retinal fluid) is also evident
from breast carcinoma is reported between 8 to 10%.1 It can on imaging and appears as highly reflective intraretinal foci
present as isolated or multiple flat or slightly elevated non (Figure 2 c,d).5
pigmented lesions with poorly defined margins that may

be associated with overlying pigment epithelial alterations, B scan shows homogenous mass with moderate to high
subretinal fluid and lipofuscin accumulation.1 In our case we internal reflectivity because metastasis from the breast has
had multiple metastasis posterior to the equator which is the solid epithelial nests or glandular structures, which act as
most common site, as the major blood supply to choroid is echo-producing interfaces, resulting in high reflectivity.
by posterior ciliary arteries. The internal acoustic reflectivity of intraocular metastatic

FAF shows hypo-autofluorescent patches (tumor surface) tumours is higher than that of most uveal melanomas but
surrounded by a sea of hyper-autofluorescence (sub clinical not as high as choroidal haemangiomas. Lateral margins of
lipofuscin in RPE). indicating that the RPE cells around and CM are poorly defined.3
overlying the tumour are damaged.2 This pattern of mixed
References

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DJO Vol. 32, No. 2, October-December 2021

1. D'Abbadie I, Arriagada R, Spielmann M, Lê MG. Cite This Article as: Sriram Simakurthy, Madhu Kumar, Om
Choroid metastases: clinical features and treatments in Shankar, Ashok Kanakamedla, Jayamadhury Gudimetla, Anurag
123 patients. Cancer. 2003;98(6):1232-1238. Shandil. Multimodal Imaging in Diagnosis of Choroidal Metastasis
in Breast Carcinoma. Delhi J Ophthalmology 2021, 32 (2): 57-59.
2. Ishida T, Ohno-Matsui K, Kaneko Y, et al. Acknowledgments: Nil
Autofluorescence of metastatic choroidal tumor. Int Conflict of interest: None declared
Ophthalmol. 2009;29(4):309-313. Source of Funding: None
Date of Submission: 11 Apr 2021
3. Perri P, Chiarelli M, Monari P, Ravalli L, Mazzeo V. Date of Acceptance: 06 Dec 2021
Choroidal metastases. Echographic experience from 42
patients. Acta Ophthalmol Suppl. 1992;(204):96-98. Address for correspondence
Om Shankar Shrivastava
4. Callaway NF, Mruthyunjaya P. Widefield imaging
of retinal and choroidal tumors. Int J Retina Vitreous. Department of Vitreoretina
2019;5(Suppl 1):49. Published 2019 Dec 12. Sankara eye hospital, Guntur,
Andhra Pradesh India
5. Al-Dahmash SA, Shields CL, Kaliki S, Johnson T, Email: [email protected]
Shields JA. Enhanced depth imaging optical coherence
tomography of choroidal metastasis in 14 eyes. Retina.
2014;34(8):1588-1593.

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DJO Vol. 32, No. 2, October-December 2021

Photo Essay

Bilateral Long Standing Exudative Retinal
Detachment in Coat’s Disease

Punita Kumari Sodhi

Department of Ophthalmology, Guru Nanak Eye Centre and Maulana Azad Medical College, New Delhi, India.

Purpose: Coat’s disease presents with an exudative retinal detachment at an early age. However, bilateral involvement is
uncommon. We present a case with bilateral long standing retinal detachment (RD) in Coat’s disease.

Methods: An 18 years old male having progressive diminution of vision from last six years had visual acuity of logmar 1.77 and
1.47 in the right eye (RE) and left eye (LE) respectively with poorly dilating pupils in both eyes. He did not have any systemic
abnormality. We did a detailed fundus examination along with fundus fluorescein angiography (FFA) and OCT.

Abstract Result: The fundus examination showed subretinal exudates with demarcation line above long standing infero-temporal RD
in RE. The LE had a self-settled RD with an atrophic temporal retina having macrocysts. There was no proliferative vireo-
retinopathy (PVR) in either eye. The fundus fluorescein angiography (FFA) showed leaks at the exudates in RE and leak at the
optic disc in LE. The OCT showed RD in RE and self-settled RD with subretinal exudate in LE.

Conclusion: The manuscript shows a bilateral long-standing exudative RD in Coat’s disease with associated features like
subretinal exudates showing leaks in angiography, demarcation line, macrocysts, retinal atrophy with underlying choroidal
flush, absence of PVR and self-settlement of RD.

Delhi J Ophthalmol 2021;32; 60-62; Doi http://dx.doi.org/10.7869/djo.720

Keywords : Bilateral Retinal Detachment; Coat’s Disease; Exudative Retinal Detachment; Long Standing Retinal Detachment; Proliferative Vitreo-

Retinopathy; Self-Settled Retinal Detachment; Sub-Retinal Exudates

Photoessay for last 6 years. The visual acuity was logmar 1.77 and 1.47

Coat’s disease, first described by George Coats in 1908, is in the right eye (RE) and left eye (LE) respectively with

an idiopathic disease characterized by aneurysmal and poorly dilating pupils in both eyes. The fundus examination

telangiectatic retinal vessels with intraretinal and subretinal showed subretinal exudates with demarcation line above

exudates. Exudative retinal detachment is a common feature. long standing infero-temporal RD in RE (Figure 1 a). The

There is a male preponderance and the disease is unilateral LE had a self-settled RD with an atrophic temporal retina

in 80-95% of cases.1 having macrocysts (Figure 2 a). There was no proliferative

A clinical picture of long-standing “bilateral” exudative vireo-retinopathy (PVR) in either eye. The fundus fluorescein
retinal detachment (RD) in an 18 years old male suffering angiography (FFA) showed leaks at the exudates in RE and
from Coat’s disease is being presented. He had progressive leak at the optic disc in LE (Figure 1b & 2b). There was a
diminution of vision and recurrent redness in both eyes choroidal flush below the temporal atrophic retina in LE.

Figure 1: (a & b) Fundus showing inferotemporal retinal detachment with subretinal exudates and fluorescein angiography showed leak at exudates &
demarcation line in right eye

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DJO Vol. 32, No. 2, October-December 2021

Figure 2: (a & b) Fundus showed temporal self-settled retinal detachment and fluorescein angiography showed leak at disc & choroidal flush below temporal
atrophic retina in the left eye

Figure 3: (a & b) OCT showing retinal detachment in the right eye and self-settled retinal detachment with subretinal exudate in the left eye

The optical coherence tomography (OCT) showed RD in RE abnormality, but had a rare presentation of bilateral
and self-settled RD with subretinal exudate in LE (Figure 3 involvement in Coat’s disease. This manuscript will enable
a & 3b). A diagnosis of bilateral long-standing exudative RD readers to see a bilateral long-standing exudative RD in
with macula off followed by self-settling of RD in LE was Coat’s disease with associated features like subretinal
made. exudates showing leaks in angiography, demarcation line,
macrocysts, retinal atrophy with underlying choroidal flush,
Discussion absence of PVR and self-settlement of retinal detachment.

Coat’s response has been inappropriately used as a blanket Compliance with Ethical Standards
term for fundus changes seen in a variety of retinopathies
including retinal vein occlusion, retinitis pigmentosa, * Disclosure of potential conflicts of interest- Author
ocular toxoplasmosis, morning glory anomaly, retinal declare that she has no conflict of interest.
macroaneurysms, retinal capillary hemangiomatosis,
familial exudative retinopathy and retinal vasoproliferative * Research involving human participants- Ethical
tumors,2,3,4 so it has been suggested to be a diagnosis of approval: All procedures performed in studies involving
exclusion.4 The typical feature is a unilateral involvement human participants were in accordance with the ethical
in a male subject presenting in the first or second decade.4,5 standards of the institutional and/or national research
The inferior and temporal quadrants of the retina are most committee and with the 1964 Helsinki declaration and
commonly involved.4 its later amendments or comparable ethical standards.
Our male subject did not have any other ocular or systemic

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DJO Vol. 32, No. 2, October-December 2021

References Cite This Article as: Punita Kumari Sodhi, Bilateral Long
Standing Exudative Retinal Detachment In Coat’s Disease. Delhi
1. Ryan SJ. Retina. Fifth Edition. New York. Elsevier. 2013. J Ophthalmol 2021;32 (2), 60 - 62.
2. Campbell FP. Coats disease and congenital vascular retinopathy. Acknowledgments: Nil
Conflict of interest: None declared
Trans Am Ophthalmol Soc. 1977;74:365-424. Source of Funding: None
3. .Woods AC, Duke JR. Coats disease. I. Review of the literature, Date of Submission: 12 May 2021
Date of Acceptance: 21 Jul 2021
diagnostic criteria, clinical findings, and plasma lipid studies. Br
J Ophthalmol 1963;47:385-412. Address for correspondence
4. Sen M, Shields CL, Honavar SG, Shields JA. Coats Disease: An Punita Kumari Sodhi, MBBS, MS
Overview of Classification, Management and Outcomes. Indian
J Ophthalmol.2019;67 (6):763-771. (Eye), DNB (Eye) Director Professor
5. Reese AB. Telangiectasia of the retina and coats disease. Am J
Ophthalmol. 1956;42:1-8. Department of Ophthalmology,
Guru Nanak Eye Centre and
Maulana Azad Medical College,
New Delhi, India
Email- [email protected]

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DJO Vol. 32, No. 2, October-December 2021

PG Snippet

Hurricane Keratopathy – “A Curlicue on The Cornea"

Vishnu Teja Gonugunta, Srinivasan Muthaiah

Department of Cornea & Refractive Surgery Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India.

Abstract Hurricane keratopathy is seen in the corneas with exaggerated epithelial cell turnover. It represents the path of proliferating
epithelium visible by collection of pigment or iron within the corneal epithelium. It should be differentiated from cornea
verticillata. Hurricane keratopathy is highlighted with fluorescein staining and not associated with drug deposition within the
epithelium. Acute postoperative corneal steepening due to the surgical induced astigmatism causing decreased wetting of the
cornea in addition to healing epithelial defect could be the cause of hurricane keratopathy appearance. Hurricane resolves
once the stimulus for rapid epithelial turnover is eliminated.

Delhi J Ophthalmol 2021;32; 63-64; Doi http://dx.doi.org/10.7869/djo721.

Keywords: Hurricane Keratopathy, Vortex Keratopathy, Healing Epithelial Defect, Contact Lens Wearers, Corneal Grafts, Whorl in the Cornea.

Case Report weak intercellular adhesions within the epithelium.
Use of topical steroids contribute in this regard.
Grayish-brown corneal epithelial lines in an anti-
clockwise whorl like fashion in the cornea of a sixty-six- Electromagnetic fields generated by the dipole of the eye can
year-old female patient who presented forty days after cause a clock wise whorl like appearance of the proliferating
undergoing a manual small-incision cataract surgery. epithelium.2
(Figure 1) Preoperatively, cornea was clear and +1.75
diopter against-the-rule astigmatism (ARA) was noted. HK is also seen in corneal grafts and contact lens wearers.3
HK is different from cornea verticillata, where the appearance
During the immediate postoperative period, an epithelial is due to drug deposition from systemic drug usage, and
defect was noted in the center of the cornea, which healed doesn’t stain with sodium fluorescein.4
well after tapering the topical gatifloxacin-dexamethasone
eye drops. HK persists as long as the stimulus for rapid epithelial
turnover is maintained and resolves from periphery to the
A hurricane keratopathy (HK) developed at the center once the stimulus is terminated.
healed epithelium site. The patient had no history of
using topical NSAIDs postoperatively or using any
systemic medications except for diabetes mellitus.

Figure 1: Hurricane keratopathy (HK). (a) Central hurricane in an anti-clock wise direction as seen with indirect illumination. (b) Optical section showing the HK
confinement to the epithelium. (c) Diffuse illumination depicting the extent of the HK and decreased corneal lustre.

The acute postoperative corneal steepening (3.50 diopter References

ARA) associated with decreased wetting of the cornea and 1. Dua HS, Watson NJ, Mathur RM, Forrester JV. Corneal epithelial
healed epithelial defect could be the cause of HK in our patient. cell migration in humans: 'hurricane and blizzard keratopathy'. Eye
During the healing of an epithelial defect, proliferation of (Lond). 1993;7:53-8.
epithelium occurs circumferentially along the limbus and from
the limbus towards the center in a curvilinear pattern assuming 2. Dua HS, Gomes JA. Clinical course of hurricane keratopathy. Br J
the shape of a hurricane within the corneal epithelium.1 Ophthalmol. 2000 ;84:285-8.

This path is normally not visualized, but becomes 3. Blanchard DL. Hurricane keratitis in penetrating keratoplasty.
highlighted when there is intracellular collection of Cornea. 1984;3:75-6. P

4. Bron AJ. Vortex patterns of the corneal epithelium. Trans

Ophthalmol Soc U K. 1973;93:455-72

material like pigment, iron, drug metabolites, glycogen

etc., HK stains with sodium fluorescein owing to the

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DJO Vol. 32, No. 2, October-December 2021

Cite This Article as Vishnu Teja Gonugunta, Srinivasan
Muthaiah. Hurricane Keratopathy –“A Curlicue on the
Cornea” Delhi J Ophthalmology 2021; 32 (2), 63- 64.
Acknowledgments: Nil
Conflict of interest: None declared
Source of Funding: None
Date of Submission: 26 Jun 2021
Date of Acceptance: 05 Dec 2021

Address for correspondence
Vishnu Teja Gonugunta

Department of of Cornea & Refractive
Surgery Services, Aravind Eye Hospital,
Madurai, Tamil Nadu, India
E-mail: [email protected]

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DJO Vol. 32, No. 2, October-December 2021

Omnibus Humanus (Masters, Change makers, Out of box thoughts)

A Legends Narrative

Ritu Aurora & Kirti Singh

Delhi J Ophthalmol 2021;32; 63-64; Doi http://dx.doi.org/10.7869/djo722

This section focuses on Change makers, Out of box thinkers and
ophthalmologists with passion for aspects other than their career

This issue salutes the humanitarian work by Dr Budhendra Kumar Jain in establishing a state of art, exemplary hospital,
the Sadguru Netra Chikitsalaya (SNC) in a rural setting. The world’s largest rural eye hospital has 25 modular operation
theatres, 79 vision centres in periphery and employs 100 ophthalmologists. Since its inception in 1968 by Param Pujya
Ranchhoddasji Maharaj and Late Shri Arvindbhai N. Mafatlal, it has conducted over 2.5 million surgeries. Situated in the
remote, holy place of Chitrakoot, Madhya Pradesh, it has become the Mecca of ophthalmic training.

His Story
After graduation from S.S Medical College, Rewa and Post-Graduation from College of Physicians and Surgeons, Mumbai,
Dr Jain joined the trust in 1974, with mission of holistic improvement in life of people in villages.
Starting from winter based eye camps aided by devotees of Gurudev, he painstakingly build his team with the selection
criteria of choosing professionals with sincerity over skills. In his words, “skill and technical know-how can always be
improved upon but interest and intent matters more”
Not compromising on quality, his credo became ‘IOL for every one’, from a time when IOL were not done for all. Today
Sadguru Netra Chikitsalaya is one of the few Eye hospitals to perform more than 1,00,000 cataract operations annually for
6 consecutive years.

His Achievements
• Enhancing life of the rural people in his state and adjoining states with his vision of “Rural development through eye

care”
• Establishing a par excellence training centre for ophthalmic surgeons recognised both Nationally & Internationally
• Making 5 rural districts cataract back-log free zones
• Establishing School of Paramedical Science in 1999 for allied ophthalmic staff.
• Ensuring comfortable living with amenities for his employees, including starting an English-medium school for children
• Starting a general hospital in Chitrakoot : Jankikund Chikitsalaya with all modern facilities for the rural patients.
• Aided by his wife Ms. Usha, managing Sadguru Siksha Samiti for rural students and Mahila Bahu-Uddeshiya Samiti, a

self-employment initiative for rural women.
• Numerous awards in recognition of his outstanding contribution. To name a few “The Life Time Achievement “ at

AIOS 2018, Dr Gullapalli Rao Endowment Award-2021, Award of Outstanding Work in Prevention of Blindness at
APAO -AIOS 2013

Excerpts from his interview with DJO
Q. Sir, What was your inspiration when you first started the Institute?
A. Gurudev was and will always be my inspiration. I also believe what Gandhiji had said: India’s soul lives in villages and
I am privileged to be able to contribute to holistic improvement in rural living.

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DJO Vol. 32, No. 2, October-December 2021

Q. When faced with challenges how do you tackle them?

A. Working in such a remote area, challenges were always there but we were determined and convinced to face each one
and make our way. We collaborated with several organisations to get expertise and guidance as I believe that only through
mutual learning can we tackle challenges.

His message to young ophthalmologists

• Be open to challenges.

• Be exposed to practise in rural settings with limited resources once in your life, not only because there is a huge need
there but this will give deeper insight in the possibilities and shape them to be better individuals.

• Inculcate compassion to see not just the Eye but the patient as a whole

• Keep on learning irrespective of where you practice

Truly Dr Jain you epitomise the immortal lines of Henry Wadsworth Longfellow : Lives of great men all remind us, we can
make our lives sublime, and, departing, leave behind us, footprints on the sands of time.

Your footprint is truly inspiring. Long live your creed.

DOI : http://dx.doi.org/10.7869/djo.679

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DJO Vol. 32, No. 2, October-December 2021

Theme Article

OCT RNFL and MACULAR GCC
Nisha Chaudhary, Neha sachdeva, Umesh

Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, India.

Abstract Subjective errors in disc evaluation and visual field analysis is one of the major factor which reduces reliability of
diagnosing and monitoring glaucoma progression. Optical coherence tomography (OCT) retinal nerve fibre layer
and macular ganglion cell complex in glaucoma are non contact, rapid and reliable methods to detect both pre
perimetric glaucoma and its progression .

Delhi J Ophthalmol 2021; 32; 67-74; Doi http://dx.doi.org/10.7869/djo.723

Keywords:Optical Coherence Tomography Retinal Nerve Fiber Layer (OCT RNFL), Macular Ganglion Cell Complex (GCC), Retinal Nerve Fiber

Layer(RNFL),Ganglion Cell Layer (GCL), Inner Plexiform layer (IPL),Optic Nerve Head (ONH).

Introduction Table 1: Thickness of Neuroretinal rim (NRR) in different devices.

The importance of clinical evaluation of optic disc and Thickness Of Neuroretinal Rim

nerve fiber layer cannot be overemphasized. Of the 1.2- 2.4 For Cirrus 5000 And Spectralis For 3D OCT-2000
million nerve fibres present, visual field changes become
evident only after minimum 35% of retinal ganglion cells are NRR is measured as MRW NRR is the distance between
damaged.1 Timely diagnosis and appropriate treatment is of (Minimum rim width) which is retinal pigment epithelium and
prime importance in glaucoma management. the distance from ILM to Bruch ILM.
membrane opening (BMO).

Pre perimetric investigations include Table 2: Analysed parapapillary circle diameter and macular area by
a) Based on Functional damage different devices
1) Frequency doubling perimetry (FDP)
2) Short wave automated perimetry (SWAP) OCT DEVICE ANALYSIS

b) Based on Structural damage Cirrus HD-OCT 5000(Carl Parapapillary circle diameter: 3.46
1) OCT RNFL AND Macular GCC Zeiss Meditec) mm Data points: 40,000
2) Ocular blood flow analysis Spectral domain OCT (SD-
OCT) Analysis area—centered on fovea: 2
mm x 2.4 mm

3) Optical coherence tomography angiography (OCTA) Spectralis (Heidelberg Parapapillary circle diameter: 3.5 mm
Engineering) Data points: 760
Note: Ocular Blood Flow analysis and OCTA are used SD-OCT with scanning laser Analysis area—centered on fovea: 10
more as modalities to investigate causes other than IOP, ophthalmoscope (SLO) x 10 mm

like vascular factors. Avanti Widefield OCT Parapapillary circle diameter: 4.0 mm
(Optovue) Analysis area—1 mm temporal to
OCT RNFL and Macular GCC SD-OCT fovea: 7 x 7 mm

Optical coherence tomography (OCT) is an evolving Optical Coherence Tomography Parapapillary circle diameter: 3.45
technology which performs high-resolution cross-sectional
imaging of tissue structure. A non invasive objective, fast RS-3000 Advance 2(NIDEK CO) Analysis area—centered on fovea: 9

SD-OCT with SLO x 9 mm

and non contact procedure it detects early structural damage 3D OCT-2000 (TOPCON Parapapillary circle diameter: 3.4 mm
by performing high resolution, cross-sectional tomographic CORPORATION) Analysis area—centered on fovea: 7
imaging of the internal microstructure in biologic systems SD-OCT x 7 mm

by measuring backscattered light.2 DRI OCT Triton (topcon) Wide-field scan (12 × 9 mm) images
Principle of OCT: Based on principle of low coherence Swept source –OCT macula and optic nerve head in a
single scan.

interferometry called Michelson interferometry. An in-vivo OCT RNFL
cross-sectional image is made from the spatial information
of tissue obtained by interference between light waves There occurs abnormal thinning of RNFL in superior and/or
reflected by both reference and sample arms.3 It has evolved inferior regions in glaucoma. Diagnostic classifications based
from time-domain, spectral-domain to swept-source with on internal normative databases with color codes help the
faster scans and higher resolution images.4 clinician. Caution has to be exercised while interpretation
of abnormal color codes in eyes with longer axial length and
Important points of OCT analysis in Glaucoma5 smaller disc area.6

Scans around the ONH, capture the measurements of RNFL Color code schemes in Cirrus HD-OCT
and ONH. Thickness of the RNFL is captured on the basis
amount of light reflected between the outer edge of RNFL A) Color code A in RNFL thickness map for depicting
and internal limiting membrane (ILM). RNFL thickness from 0-350 microns where warm colors
(yellow,red) represent thicker RNFL and cold colors

Macular analysis is done in a rectangular area which is blue,green) represent thinner RNFL.

centered on fovea and include analysis of ganglion cell - B) Color code B is based on distribution of different
internal plexiform layer (GC-IPL) thickness and ganglion parameters in normative database of Cirrus HD-OCT.
cell complexes (GCC).Thickness measurements are shown Measurements beyond normative database are shaded
in a TSNIT (temporal, superior, nasal, inferior, temporal) grey,those within thickest 5% of normal are white,those
configuration and are compared to age-matched controls.

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Figure 1: Interpretation of OCT RNFL map. Picture Courtesy: Akman A et al. Optical coherence tomography in glaucoma: A practical guide(ebook).
Springer,2018: p.43

within 5-95% limits are shown by green, those between 3. RNFL thickness map.
1-5% are yellow(borderline abnormal) and those below It gives the raw RNFL thickness data using color code A
1% of normal are red. without any comparison with normative data.

C) Color code C is based on reflectance of tisssue layers. 4.Neuro-retinal rim thickness plot
Hot colors (red,yellow) represents layers with high The neuroretinal rim compared with age and disc size
reflectance and cold colors (blue ,black) represents those matched data of normative database is depicted in temporal-
with low reflectance. superior-nasal-inferior and temporal TSNIT configuration.

1.Patient Data & Signal Strength 5. RNFL Deviation map
Date of birth has to be entered correctly, for age matched Any region not red or yellow lies within normal limits.
database to be applicable.Signal strength serves as a Purple circle is the calculation circle, black circle – BMO
quality measure and should be more than7 (depending (Bruch’s Membrane Opening) circle and Red circle – cup
on machine).Poor signal strength can be due to lenticular border
opacification,posterior capsular opacification and ocular
surface disease.Poor quality scan can also occur due to poor 6 .RNFL Thickness TSNIT plot
centration or inexperienced operator. It uses a 3.46mm calculation circle.Normal eyes have a
typical “Double Hump” configuration.
2. Key parameter table
Different parametres are compared with age matched 7. RNFL Quadrant and Clock-hour graphs
normative data using color code B. It summaries the RNFL thickness TSNIT plot and gives a
quadrant and clockwise RNFL thickness.

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DJO Vol. 32, No. 2, October-December 2021

8. Extracted Vertical and Horizontal Tomograms mimickers, corneal hysteresis affecting IOP measurements,
Horizontal and Vertical B-scans of Optic Disc are difficulty in distinguishing gamma from Beta zone in
obtained from the 6 x 6 cube. These B scans confirm the PPA, OCT values being outside the normative database in
cup configuration and identify artifacts related to NRR myopes, normal volume scan of depth of focus of 2mm often
measurements.It is depicted by Color code C which is based exceeded in myopic eyes, magnification error and vitreous
on reflectance. opacities obscuring light reflection.
GREEN disease is seen in myelinated nerve fibre and
9.RNFL circular tomogram posterior vitreous detachment(PVD).Weiss ring can cause
It gives the raw OCT image of the calculation circle. Artifacts both red or green disease, as it blocks the OCT signal in
and segmentation errors are checked here. different areas of ONH or retina. Careful inspection of
RNFL thickness map, deviation map and TSNIT graph helps
Limitations to identify this artifact. Weiss ring can also lead to green
disease in cases where scanning is done through incorrect
Floor Effect calculation circle.
RNFL thickness does not go beyond 30-40 microns due
to residual glial tissue and vasculature. For advanced OCT MACULAR Ganglion cell complex(GCC)
disease OCT thus becomes unreliable for detecting further
progression. Macula,5.5 mm in diameter, has the highest density of
RGCs though it occupies less than 2% of retinal area.
Poor Quality Scan causes Macular thickness can be affected in glaucomatous eyes
A) Patients factors: Lenticular opacification, ocular surface and may represent RGCs damage.However outer retinal
disease, motion artefacts (confirmed by break in continuity layers contribute approximately 65% of total retinal
of blood vessels). thickness,making macular thickness alone not a totally
appropriate parameter in glaucomatous patient.OCT RNFL
B) Machine factors: Poor Device performance and poor analyzes the axonal portion of the RGCs without considering
centration. the cell bodies and dendrites, which are also affected in
Segmentation error – glaucoma and reside in ganglion cell layer (GCL) and inner
RED disease occurs in high myopes and tilted disc. Glaucoma
diagnosis in myopia is difficult due to visual field changes

Figure 2: OCT RNFL printout of a glaucoma patient. Picture courtesy: Guru Nanak Eye Centre, New Delhi

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DJO Vol. 32, No. 2, October-December 2021

Figure 3: OCT RNFL printout showing floor effect in left eye with advanced glaucoma in left eye. Picture courtesy: Guru Nanak Eye Centre, New Delhi

Figure 4: OCT RNFL printout showing motion artifact depicted by break in continuity of blood vessels,
despite good quality index/signal strength. Picture courtesy: Guru Nanak Eye Centre, New Delhi.

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DJO Vol. 32, No. 2, October-December 2021

Figure 5: OCT RNFL printout of a healthy myopic patient shows red-color regions of the RNFL (false- positive results), based on the built-in normative database
(RED disease).Picture courtesy: Guru Nanak Eye Centre, New Delhi.

Figure 6: Spectralis OCT RNFL printout showing a thick RNFL in both eyes (left thicker than right -red arrowheads) with segmentation problems depicting green
disease. Picture courtesy: Akman A et al. Optical coherence tomography in glaucoma: A practical guide(ebook).Springer,2018: p 121.

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Figure 7:OCT RNFL printout showing red disease in case of blocked signals due Figure 8: OCT Macular GCC printout interpretation. Picture courtesy: Akman
to Weiss ring.Picture courtesy: Akman A et al. Optical coherence tomography A et al. Optical coherence tomography in glaucoma: A practical guide(ebook).

in glaucoma: A practical guide (ebook).Springer,2018:p 137 Springer,2018: p 49.

Figure 10: (a) and (b) showing two page printout of the Cirrus HD-OCT macular ganglion cell GPA Report. Picture courtesy: Akman A et al. Optical coherence
tomography in glaucoma: A practical guide(ebook).Springer,2018: p 258.

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Figure 9: OCT Macular GCC of patient with advanced glaucoma. Picture courtesy: Guru Nanak Eye Centre, New Delhi.

plexiform layer(IPL). Macular GCC measures the following: and an outer elliptical area where sectoral measurements
provided using color Code B. Thickness table gives the
Thickness of Ganglion cell-inner plexiform layer (GCIPL) average and minimum GCL +IPL thickness.
= sum of the thicknesses of GCL and IPL

Ganglion cell complex (GCC) thickness = sum of the Horizontal tomogram must pass through fovea and is for

thicknesses of the RNFL,GCL and IPL.7 detection of Macular pathologies using color Code C

The temporal border of optic disc receives RGC axons from Diagnostic ability of GCC in advanced glaucoma may
superior macula, while inferotemporal border of the optic be inferior to RNFL parameters because only 50% of
disc receives RGC axons from inferior macula.Glaucomatous the RGCs occupy the macula. With best parameters for
defects dominate in the latter referred to as “macular detecting perimetric glaucoma being average GCC thickness
vulnerability zone (MVZ)” by Hood et al.8,9 Temporal area and inferior GCC thickness,,the rate of GCIPL thinning
called as temporal raphe has relatively few axons as the RGC reportedly is significantly faster in glaucomatous eyes
axons don’t cross the horizontal meridian.Most macular with progression.12-15 Minimum GCIPL thickness has been
change in glaucomatous eyes appears in temporal macular found to be the best parameter for discriminating early-
regions along the horizontal raphe.10 Best OCT parameters glaucomatous change from normal eyes.16 Comparing
in differentiating preperimetric glaucoma included GCC ability of GCC in detecting early glaucoma with respect to
average thickness, inferior quadrant RNFL thickness, other OCT parameters, the area under the curve (AUC) is
inferior GCC thickness and superior GCC thickness.11 also significantly higher in the GCC-related thicknesses
Interpreting an than in corresponding GCL/IPL or RNFL thickness.17,18
Many authors report GCC thickness to be a better diagnostic
OCT Macula GCC Report biomarker for early glaucoma than RNFL thickness.19

Thickness Map gives the raw GCL+IPL thickness and is Guided progression analysis compares the individual’s
not related to values from normative database.The normal parameters over time with normative database. Assessment
value is 92.11+-5.48 microns and is depicted in Color Code of progressive changes in optic disc and RNFL is based on
A. Sector map shows a central elliptical region, 1.2 x 1.0mm, event and trend analysis. Event-based analysis helps in
representing fovea where GCL+IPL thickness is minimum

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detecting progression when a subsequent measurement power of optic disc morphology, peripapillary retinal nerve
exceeds a pre-established threshold for change from fiber layer thickness, and macular inner retinal layer thickness
baseline. Progression is given by trend-based analysis when in glaucoma diagnosis with fourier-domain optical coherence
a significant negative slope is detected using linear regression tomography. J Glaucoma. 2011;20(2):87–94.
analysis.20 Monitoring of macular parameters facilitates 15 Lee WJ, Kim YK, Park KH, Jeoung JW. Trend-based analysis of
detection of structural progression in glaucomatous eyes ganglion cell-inner plexiform layer thicknesschanges on optical
and prediction of subsequent visual field defects. The coherence tomography in glaucoma progression. Ophthalmology.
Guided Progression Analysis of Cirrus HD-OCT performs 2017c;124
event analysis of the RNFL thickness maps and gives the 16 Mwanza JC, Durbin MK, Budenz DL, et al. Glaucoma diagnostic
area of change in the same. In Spectralis OCT, eye-tracking accuracy of ganglion cell-inner plexiform layer thickness:
improves reproducibility, which in turn leads to better comparison with nerve fiber layer and optic nerve head.
accurate detection of glaucoma progression. Ophthalmology. 2012;119(6):1151–8.
17 Nakatani Y, Higashide T, Ohkubo S, Sugiyama K. Influences of
Conclusion inner retinal sublayers and analytical areas in macular scans by
spectral-domain OCT on the diagnostic ability of early glaucoma.
OCT provides an excellent opportunity to study the RNFL Invest Ophthalmol Vis Sci. 2014;55(11):7479–7485.
objectively which adds to diagnostic evidence to help in 18. Cennamo G, Montorio D, Romano MR, et al. Structure-functional
clinical assessment and to quantify glaucoma progression; parameters in differentiating between patients with different
however, limitations related to normative databases and degrees of glaucoma. J Glaucoma. 2016;25(10):e884–e888.
imaging artifacts should be kept in mind. The estimation 19 Kim NR, Lee ES, Seong GJ, Kim JH, An HG, Kim CY. Structure-
of glaucoma-induced RGCs loss by using GCC parameters function relationship and diagnostic value of macular ganglion
represents an ideal predictor in assessing early glaucoma cell complex measurement using Fourier-domain OCT in
and offers a more accurate tracking of glaucoma progression. glaucoma. Invest Ophthalmol Vis Sci. 2010;51(9):4646–4651.
20 Bussel, II, Wollstein G, Schuman JS. OCT for glaucoma diagnosis,
References screening and detection of glaucoma progression. Br J
Ophthalmol. 2014;98 Suppl 2(Suppl2):ii15–9
1 Kerrigan-Baumrind LA, Quigley HA, Pease ME, Kerrigan
DF, Mitchell RS. Number of ganglion cells in glaucoma eyes Cite This Article as: Nisha Chaudhary, Neha sachdeva, Umesh,
compared with threshold visual field tests in the same persons. OCT RNFL and Macular GCC. Delhi J Ophthalmol 2021 32 (2) 67 -74.
Invest Ophthalmol Vis Sci. 2000;41(3):741–748.
Acknowledgments: Nil
2 Aref AA, Budenz DL. Spectral domain optical coherence
tomography in the diagnosis and management of glaucoma. Conflict of interest: None declared
Ophthalmic Surg Lasers Imaging 2010;41:S15-27
Source of Funding: None
3 Popescu D. P. et al, “Optical coherence tomography: fundamental
principles, instrumental designs and biomedical applications,” Date of Submission 23 July 2021
Biophys. Rev. 3(3), 155–169 (2011).10.1007/s12551-011-0054-7. Date of Acceptance: 22 Dec 2021

4 Duker JS, Waheed NK, Goldman D. Handbook of Retinal OCT: Address for correspondence
Optical Coherence Tomography. Saunders; 2014.
Nisha Chaudhary,
5 Aref A, Rosdahl J. Focal Points 2019 Module: Optical Coherence
Tomography in Glaucoma Diagnosis. In: Eric P. Purdy M, Senior Resident Ophthalmology
ed. Vol XXXVII. San Francisco, CA: American Academy of Department of Ophthalmology, Guru
Ophthalmology; 2019 Nanak eye centre,
New Delhi, India.
6 Kim KE, Jeoung JW, Park KH, Kim DM, Kim SH. Diagnostic E mail: [email protected]
classification of macular ganglion cell and retinal nerve fiber
layer analysis: differentiation of false-positives from glaucoma. Quick Response Code
Ophthalmology. 2015;122(3):502–10.

7 Ishikawa H. Where does ganglion cell analysis fit? Glaucoma
Today 2016. Available at: http://glaucomatoday.com/2016/06/
where-does-ganglion-cell-anaylsis-fit/ [Accessed January 4, 2018].

8 Hood DC. Improving our understanding, and detection of
glaucomatous damage: An approach based upon optical
coherence tomography (OCT). Prog Retin Eye Res. 2017;57:4675.

9 Hood DC, Raza AS, de Moraes CG, Liebmann JM, Ritch R.
Glaucomatous damage of the macula. Prog Retin Eye Res.
2013;32:1–21.

10 Park KH,KimTW.OCT Imaging in Glaucoma.
Singapore:Springer;2021.29p

11 Scuderi G, Fragiotta S, Scuderi L, Iodice CM, Perdicchi A. Ganglion
cell complex analysis in glaucoma patients: what can it tell us?
Eye Brain. (2020) 12:33–44. 10.2147/EB.S226319

12 Tan O, Chopra V, Lu AT, et al. Detection of macular ganglion
cell loss in glaucoma by Fourier-domain optical coherence
tomography. Ophthalmology. 2009;116(12):2305-2314e2301-2302.

13 Rao HL, Zangwill LM, Weinreb RN, Sample PA, Alencar LM,
Medeiros FA. Comparison of different spectral domain optical
coherence tomography scanning areas for glaucoma diagnosis.
Ophthalmology. 2010;117(9):1692–1699,

14 Huang JY, Pekmezci M, Mesiwala N, Kao A, Lin S. Diagnostic

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Theme Article

Anterior Segment Optical Coherence Tomography in Glaucoma
Arshi Singh
Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, India.

Abstract Anterior segment optical coherence tomography (AS OCT) is a non-invasive imaging modality which provides a
quantitative assessment of subconjunctival space, angle of anterior chamber and lens position. For angle closure
glaucoma, it is useful as a screening tool, understanding of the disease pathophysiology and predicting outcomes of
lens surgery. In open angle glaucoma, its primary use is to monitor success of filtering surgeries like trabeculectomy
or tube shunt by detailing bleb morphology and identifying early failure. By quantifying dimensions of angle, iris,
cornea in real time, it aids in deciding laser or surgical intervention. The rapid, non-contact, high resolution image
acquisition with ruler function, make this a valuable research tool. The review provides a comprehensive summary
on principles, relevance, uses and limitations and advances of ASOCT in glaucoma practise.

Delhi J Ophthalmol 2021; 32; 75-81; Doi http://dx.doi.org/10.7869/djo.724

Keywords:Anterior Segment Optical Coherence Tomography (ASOCT), Glaucoma Diagnosis, Angle Anatomy, Bleb Morphology

Introduction Image resolution is better than UBM. Imaging is rapid

Anterior segment optical coherence tomography has and visualizes all four quadrants in single scan unlike
evolved from the time domain prototype (830nm) used UBM. This tool has a shorter learning curve, with less
to image posterior and anterior structures to dedicated inter operator variability compared to UBM.

systems using longer wavelength of 1310 nm for deeper • Over Gonioscopy: ASOCT scores by being non-contact,
penetration.1 Hence, the anterior segment Optical coherence providing 360 degree and objective quantification
tomography (AS- OCT) devices are classified according to of angle along with measurement of iris thickness.
wavelength used However, clarity of angle structures, additional details
of synechia, pseudoexfoliation, neovascularization etc
a. Dedicated ASOCT uses 1310 nm wavelength: Visante are much better seen on gonioscopy. Indentation or
(Zeiss), Slit lamp SL-OCT (Heidelberg), Casia (Tomey). manipulation cannot be performed, therefore synechial
The longer wavelength reduces scattering of light by closure cannot be differentiated from appositional
sclera, thereby permitting detailed resolution of anterior closure of angle. Iris configuration and iris insertion
chamber angle structure. Technology has evolved from details are also much better visualized on gonioscopy.
the Time Domain Visante (axial resolution 15 µm) to The use of infrared laser with real time eye positioning
Fourier domain Swept Source Casia (axial resolution permits more precise capture of angle details under
10 µm), with increased scan speed resulting in mesopic and scotopic conditions. Many studies
measurement of entire angle within 2-3seconds. however report that ASOCT over estimates angle
closure, particularly in superior and inferior quadrants,
b. Combined AS and Posterior segment OCT uses 820- probably due to variations in iris profile and level of
840 nm wavelength: Spectralis OCT (Heidelberg irido-angle contact.7,8
Engineering Inc), Cirrus HD-OCT (Carl Zeiss Meditec
Inc), RTVue (Optovue Inc). This shorter-wavelength In addition, definition of angle closure is different. In
does give good axial resolution but has the inherent gonioscopy- it is non-visibility of posterior trabecular
problem of limited penetration.2,3 meshwork whereas in ASOCT it is defined as
iridotrabecular contact.9,10 Till date ASOCT does not
The AS-OCT image is a gray scale or false colour provide sufficient information about angle anatomy to
2-dimensional cross sectional representation of backscattered be considered a substitute for gonioscopy as screening
light intensity. The structures seen are cornea, angle and tool for ACG.
angle recess, sclera and scleral spur (highly reflective),
iris and its root, ciliary body and ciliary body band (hypo
reflective) and limbus.

Comparison with ultrasound biomicroscopy and gonioscopy Clinical Utility in Glaucoma

• Over ultrasound biomicroscopy (UBM): AS- OCT scores A. In Angle closure disease (ACG)
by being non-invasive, non-contact procedure.4,5 It can 1. Angle quantification: Extensively used for this purpose,
be safely used in imaging angle, limbus and filtering
bleb in postoperative period of filtering surgery and in ASOCT relies on identification of scleral spur (SS) as the
situations of anterior segment trauma. pivotal landmark. Scleral spur is the highly reflective
structure at intersection of ciliary muscle with inner
Supine position required in UBM causes widening corneal margin. It is identified as a bump‑like structure
of angle due to posterior shift of lens iris diaphragm.4 in inner corneal meshwork margin.6 (Figure 1) Trabecular
The sitting posture makes ASOCT more patient and meshwork is located 250-500 μm anterior to SS.
operator friendly.
ASOCT nomenclature for angle parameters

However, since ASOCT waves are absorbed by iris • Trabecular iris angle (TIA): Angle with apex in iris
pigment epithelium, structures posterior to iris like recess, arms through a point on TM 500 or 750 μm from
ciliary body are not visualized.6 scleral spur and perpendicular on surface of iris.11

• Angle opening distance (AOD): Perpendicular distance

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Figure 1: Identification of Scleral spur (arrow) Figure 2: Angle parameters: Trabecular iris angle (TIA), angle-opening distance
(AOD), trabecular iris space area (TISA), and angle recess area (ARA).15
between trabecular meshwork and iris at 500 μm anterior
to SS. The figure of 500 μm is the theoretical location of the inner corneoscleral wall; and inferiorly by the iris
trabecular meshwork. Since all measurements are done in surface.14 TISA does not require clear visualization of
iris plane; peripheral synechiae, alterations in iris contour angle recess. (Figure 2) It is a better indicator of actual
and curvature confound AOD measures. To compensate, filtering area, since it excludes non-filtering area posterior
AOD 750 μm parameter can be used, which by covering to SS. It is a sensitive identifier of narrow angles in eyes
more area is less affected by iris surface irregularities.12 with deep angle recesses and has better correlation with
• Angle recess area (ARA): Is a triangular area with corneal gonioscopy compared to AOD or ARA.
endothelium (base), angle recess (apex) and perpendicular
line 500-750 μm anterior to SS from iris surface to corneal 2. Anterior chamber parameters 16
endothelium.13 This parameter overcomes confounders • AC width: Is the distance between two scleral spurs
of AOD and measures entire contour of the iris surface. • Anterior chamber depth: Area between corneal
The area being posterior to SS represents the non-filtering
portion of angle. Poor visualization of angle recess is the endothelium to anterior lens surface
common problem faced in ARA measurement. • Anterior chamber area (ARA): Is cross-sectional area

• Trabecular iris space area (TISA): Is a trapezoidal area, bounded by endothelium, anterior surface of iris, anterior
with following boundaries. TISA 500 is an area bounded surface of lens (inside pupil).
anteriorly by the AOD 500; posteriorly by a line drawn • Anterior chamber volume (ACV): This parameter has been
from the scleral spur perpendicular to the plane of the related to risk of developing PAC. ASOCT demonstrates
inner scleral wall to the opposing iris; superiorly by significant increase in ACV after iridotomy. 16,17

3. Iris parameters
• Iris thickness (750 and 2000): Is measured at 750 and 2000

Figure 3: 3D Gonioscopic view and ITC Graph shown on AS OCT9

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Figure 4: AS-OCT imaging on Visante (Carl Zeiss Meditec, Dublin, CA) showing lens vault, anterior vault19

µm from SS. Most studies confirm iris to be thicker in • Lenticular thickness (LT): Is measured from anterior
Orientals and Indians 18 surface of lens to posterior surface. Usually done by
biometry or IOL master.
• Iris curvature (I Curv): Is the line drawn from most
peripheral to most central point of iris pigment epithelium. 5. Risk factors for angle closure
ASOCT has identified additional risk factors for angle
A perpendicular line is extended from this line to iris
pigment epithelium at point of greatest convexity. A closure other than previously known shallow anterior
gender link has been seen for this with more convex iris chamber depth and short axial length.
being seen in women in Chinese population.18 • Angle : Small anterior segment dimensions have been
confirmed , with TISA750, IT 750 being recognized for
• Iris area: Is the cross-sectional area of iris. ACG by studies20
• Irido-trabecular contact index (ITC): Extent of angle • Lens: Greater lens vault (LV), or anteriorly positioned
lens has been identified as an independent significant risk
closure (contact between iris and angle wall anterior to factor for angle closure 20,21,22
SS) expressed as percentage . It is calculated by software • Iris – larger iris area, curvature and iris thickness are
analysis of SS-OCT image of entire circumference of independent risk factors for narrow angles 23
angle in Casia. The ITC chart is generated with blue area
denoting amount and distribution of ITC. (Figure 3) The 6. Understanding disease pathophysiology
green line drawn above red line (representing SS) depicts Biometric parameters on ASOCT have given an insight
amount of angle closure. Positive ITC (angle closure) is
shown above red line and negative ITC open angles) into understanding disease pathophysiology of complex
below the red line. A recent study by Baskaran et al. angle closure mechanisms like plateau iris.
demonstrated that the ITC index has good diagnostic • Plateau iris syndrome presents with occludable angles
performance compared to gonioscopy for estimating the on gonioscopy, flat iris plane and a relatively deep
degree of angle closure.6 central anterior chamber. (Figure 5) Its non- pupil block
mechanism was clearly outlined by UBM imaging,
4. Lens parameters documenting anterior anteriorly directed ciliary processes
• Lens vault (LV): Is the perpendicular distance between propping up the peripheral, iris and causing iris root
angulation. This peripheral angulation is the cause of
anterior pole of crystalline lens & horizontal line joining persistent occludable angle after patent iridotomy.24
two SSs. (Figure 4)

Figure 5: Plateau iris configuration. Narrow angle, deep central anterior chamber narrow, sharp bend in peripheral iris (propped up) while rest iris is flat.29

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Features of flat central iris, absent ciliary sulcus with spaces, fibrosis or scarring and scleral opening. The
irido angle contact in at least two quadrants are the UBM non-contact nature of the test makes it a useful tool in
criteria for plateau iris.25 Recent deep-learning module on immediate post operative period and in fragile thin blebs.
ASOCT demonstrates a high performance in predicting
plateau iris.26 Mature blebs with thicker hypo-reflective walls, large internal
fluid filled cavities, presence of microcysts (collections of
• Predicting lens induced glaucoma: eyes with larger lens aqueous humour), an extensive hyporeflective area and
vault, larger iris area progress to lens induced angle internal ostia indicate good filtration.31 Longitudinal studies
closure after mydriasis, eg. for microspherophakia over 6 months have linked low bleb wall reflectivity with
multiple internal layers and microcysts with success.32
• In malignant glaucoma; demonstration of forward Khamar et al. described bleb wall reflectivity as two types,
movement of lens, angle closure and flat chamber. multiform or uniform reflectivity; with the latter denoting
poor function.33 One can quantify the bleb assessment by
• Secondary angle closure from IOL related complications, using the ruler option and measuring the maximum length
phakic IOL, neovascular glaucoma, post-vitrectomy, and height of internal fluid-filled cavity, bleb wall thickness,
silicone related glaucoma, iridocorneal endothelial number of microcysts in bleb wall etc.
syndrome and epithelial downgrowth all can be
visualized by ASOCT. Another classification of ASOCT defined bleb morphology
patterns is: 34
7 .Therapeutic efficacy of laser PI and iridoplasty • Diffuse filtering bleb - subconjunctival fluid-filled spaces
ASOCT can evaluate suitability and predict outcomes
with low to moderate intrableb reflectivity
of laser or surgical approaches. It is also used to check • Cystic bleb - fluid filled spaces, thickened tenon capsule
efficacy of laser procedures like iridotomy, iridoplasty
etc. with large hyporeflective area
Post prophylactic LPI, documents reduction in angle • Encapsulated bleb - clear fluid-filled space surrounded by
widening at 6 months, which points to role of non-
pupillary block mechanisms in primary angle-closure dense connective tissue of high signal reflectivity
glaucoma.28 Response of iridoplasty in plateau iris can be • Flat bleb - no bleb elevation, high episcleral reflectivity
visualized by ASOCT, demonstrating open angles with
thinning of root of iris, suggestive of scarring. 28 denote episcleral fibrosis. (Figure 7)

B. Open angle glaucoma (OAG) AS OCT guided bleb evaluation in the early post operative
AS OCT guided images aid in understanding period can help in decision for earlier intervention for
blebs destined to fail. A new technology, the polarization
pathophysiology. Reduced schlemm’s canal area (slit- sensitive anterior OCT uses birefringence to evaluate phase
shaped dark area on inner part of limbus) in primary retardation of biological fibrous tissues thereby identifying
open angle glaucoma cases points to SC alterations.10 early intra-bleb fibrosis.35
The tool can provide collaboratory evidence in glaucoma
secondary to pigment dispersion syndrome (concave D. Glaucoma drainage devices
iris), Axenfeld-Rieger’s anomaly, lens particle induced AS-OCT provides high-resolution imaging for glaucoma
glaucoma and some types of traumatic glaucoma. drainage devices, which helps in knowing the position,
patency, state of drainage, impending tube erosion,
C. Post filtering surgery: intraluminal deposits, intraluminal suture and can also show
Bleb morphology is a surrogate marker for assessing any tube-corneal or tube-iris touch.9,36 (Figure 8) It helps in
assessing tubes implanted into ciliary sulcus and implants
bleb function and future bleb success.30 AS OCT -cross
sectional images of internal bleb structure helps assess
bleb wall thickness, area, volume, optically empty cystic

Figure 6: Pre- and Post- laser (6 months) temporal angle measurements showing widening

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Figure 7: ASOCT showing (a) diffuse (b) cystic, (c) encapsulated and (d) fibrosed bleb respectively

placed in suprachoroidal space (Cypas or gold supra- and without sedation. HH-OCT can be used to assess
choroidal microshunt).9 Jung et al identified successful blebs corneal thickness (thicker in PCG) and internal contour of
of Ahmed glaucoma valves to have thinner maximum bleb endothelium; structure of iris (thinner with high insertion)
wall.37 and irido-corneal angle in PCG. Excellent visualisation

E. In Primary congenital glaucoma (PCG) of iris insertion indicates potential for AS-OCT to help in
Anterior high resolution (HH) OCT has significant potential surgical planning of type of surgery and location of incision.
to improve diagnosis and management of PCG. Clinically Intraoperative OCT may in future be used to find segments
relevant information can be obtained non-invasively most affected by anterior position of the iris, to control

Figure 8: Tube patent OU with tube away from cornea (a), tube touch (b) OS , with functional bleb (c)

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localisation and depth of incision and determine position of of the anterior chamber in angle-closure glaucoma patients. Korean
tube shunts or valves.38 J Ophthalmol. 2002;16(1):20-25.
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• Due to poor penetration of iris pigment epithelium, this 13. Ishikawa H, Yemi K. A new method of quantifying angle
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Optical Coherence Tomography: A Comparison between Slit Lamp 29. Bayer A. Anterior segment optical coherence tomography in
OCT and Visante OCT Invest Ophthalmol Vis Sci. 2008;49,8: 3469- glaucoma. In: Akman A, Bayer A, Nouri-Mahdavi K. Editors.
74. Optical Coherence Tomography in Glaucoma -A practical guide.
6. Maslin JS, Barkana Y, Dorairaj SK. Anterior segment imaging in Springer. 2018. p217-234.
glaucoma: An updated review. Indian J Ophthalmol 2015;63: 630-40 30. Hong J, Xu J, Wei A. Spectral-domain optical coherence tomographic
7. Nolan W, See JL, Chew PTK, Friedman DS, Smith SD, assessment of Schlemm’s canal in Chinese subjects with primary
Radhakrishnan S et al. Detection of Primary Angle Closure Using open-angle glaucoma. Ophthalmology. 2013; 120: 709-15.
ASOCT in Asian Eyes. Ophthalmology. 2007; 114(1):33-9. 31. Wells AP, Crowston JG, Marks J, Kirwan JF, Smith G, Clarke JC,
8. SakataLM, LavanyaR, FriedmanDS, AungHT, GaoH, et al. A pilot study of a system for grading of drainage blebs afer
KumarRS,etal. Comparison of gonioscopy and anterior segment glaucoma surgery. J Glaucoma 2004;13: 454‑60.
ocular coherence tomography in detecting angle closure in different 32. Kawana K, Kiuchi T, Yasuno Y, Oshika T. Evaluation of
quadrants of the anterior chamber angle. Ophthalmology 2008; 115:
769‑74.
9. Angmo D, Nongpiur ME, Sharma R, Sidhu T, Sihota R, Dada T.
Clinical utility of anterior segment swept-source optical coherence
tomography in glaucoma. Oman J Ophthalmol. 2016;9(1):3-10.
10. Asrani S, Sarunic M, Santiago C, Izatt J. Detailed visualization
of the anterior segment using fourier-domain optical coherence
tomography. Arch Ophthalmol. 2008;126(6):765-771.
11. Cho HJ, Woo JM, Yang KJ. Ultrasound biomicroscopic dimensions

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trabeculectomy blebs using 3‑dimensional cornea and anterior Cite This Article as: Anterior Segment Optical Coherence
segment optical coherence tomography. Ophthalmology 2009; 116: Tomography in Glaucoma Delhi J Ophthalmol 2021; 32 (2):
848‑55. 75 - 81.
33. Khamar MB, Soni SR, Mehta SV, Srivastava S, Vasavada VA. Acknowledgments: Nil
Morphology of functioning trabeculectomy blebs using anterior Conflict of interest: None declared
segment optical coherence tomography. Indian J Ophthalmol 2014; Source of Funding: None
62: 711‑4. Date of Submission: 21 Nov 2021
34. Leung CK, Yick DW, Kwong YY, Li FC, Leung DY, Mohamed S, et Date of Acceptance: 06 Dec 2021
al. Analysis of bleb morphology after trabeculectomy with Visante
anterior segment optical coherence tomography. Br J Ophthalmol. Address for correspondence
2007, 91:340–4. Arshi Singh Senior Resident
35. .Fukuda S, Beheregaray S, Kasaragod D, Hoshi S, Kishino G, Ishii
K, et al. Noninvasive evaluation of phase retardation in blebs after Department of Ophthalmology, Guru
glaucoma surgery using anterior segment polarization‑sensitive Nanak Eye Centre, New Delhi, India.
optical coherence tomography. Invest Ophthalmol Vis Sci 2014; 55: E-mail: [email protected]
5200‑6.
36. Alvarado JA, Srivastava V, Sun Y. Intraluminal Deposits Found in
Glaucoma Tube Shunts Via Anterior Segment Ocular Coherence
Tomography. J Glaucoma. 2018 ;27(3):e68-e71.
37. Jung KI, Lim SA, Park H-YL, Park CK. Visualization of blebs using
anterior segment optical coherence tomography after glaucoma
drainage implant surgery. Ophthalmology 2013; 120:978–983.
38. Pilat AV, Proudlock FA, Shah S, Sheth V, Purohit R, Abbot
J,et al. Assessment of the anterior segment of patients with
primary congenital glaucoma using handheld optical coherence
tomography. Eye (Lond). 2019;33(8):1232-1239.
39. Sathyan P, Shilpa S, Anitha A. Optical Coherence Tomography in
Glaucoma. J Curr Glaucoma Pract. 2012;6(1):1-5.
40. Parc C, Laloum J, Berges O. Comparison of optical coherence
tomography and ultrasound biomicroscopy for detection of plateau
iris. J Fr Ophtalmol. 2010; 33(4): 266–273.

Quick Response Code

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DJO Vol. 32, No. 2, October-December 2021

Theme Article

UBM Imaging

Shweta Viswanath, Shikha Gupta

Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, India.

Ultrasound biomicroscopy is a non-invasive modality of imaging used for visualization of anterior ocular structures

Abstract that are obscured by the normal as well as pathological relations. This article gives an overview of the imaging
technique and its application in ophthalmology.

Delhi J Ophthalmol 2021; 32; 82-85; Doi http://dx.doi.org/10.7869/djo.725

Keywords:UBM, Anterior segment, Glaucoma.

Introduction

Ultrasound biomicroscopy is a modality of imaging that
allows evaluation of the ocular structures in the anterior
segment regardless of the optical media clarity. The
principle is the same as that of any ultrasound imaging, but
here ultrasound frequency used is in the range 35MHz to
100MHz.1 This frequency confers very high resolution but
limited penetration making this imaging modality ideal for
anterior segment structures. It gives a resolution of up to
20µm axially and 50µm laterally with penetration of 4-5mm.1

The technique of imaging2 Figure 2: UBM showing hyper reflective Bowman’s membrane (arrow)
• The patient is placed in a supine position fixating in the and descemet’s membrane(arrow head). The stroma shows low irregular
primary gaze.
• A topical anesthetic agent is instilled and a silicone cup reflectivity.
(22-24mm diameter) is placed that keeps the eyelid
separated. • To rule out Descemet membrane detachment (DMD) in
• After ensuring proper seal, the cup is filled with normal cases of corneal edema, though the preferred modality
saline. Some examiners also use methylcellulose (1%- remains AS-OCT.
2.5%) as a coupling fluid.
• The transducer should be placed within the coupling • For measurement of sulcus-to-sulcus diameter
solution in such a way that the scanning beam strikes preoperatively for Implantable Collamer Lens (ICL)
the target perpendicularly, taking care not to apply and postoperative lens vault measurement (the distance
undue pressure on the cup (Figure 1) between center of ICL and anterior crystalline lens
surface).
Figure 1: Figure shows the technique of UBM)
OCULAR SURFACE TUMORS
Applications of UBM in ophthalmology The UBM can provide information about echogenicity,

CORNEA reflectivity, depth of involvement of the mass on the
Cornea is the first structure to be visualized on UBM. The ocular surface, and involvement of adjacent structures
different layers can be delineated based on the variation in that aid in diagnosis as well as planning the management
reflectivity(Figure 2). of the patient. It also helps in following up the patient
who has undergone surgical excision to look for any
UBM gives useful information in the following conditions: residual tumor or recurrences.3
• To examine the anterior chamber and lens status in an

opaque cornea.
• Measurement of central corneal thickness and depth of EPISCLERA and SCLERA
UBM can be used to differentiate scleritis episcleritis as
corneal opacity
well as different types of scleritis
The reflectivity of scleral and episcleral tissue appears

hyper-reflective in case of inflammation and depth of
inflammation can help us to come to a diagnosis and
proper management. The sclera also appears thickened
in cases of scleritis.

ANTERIOR CHAMBER and ANTERIOR CHAMBER
ANGLE

The Anterior chamber can be seen as anechoic space
between the posterior surface of the cornea and the
anterior surface of the iris and lens.UBM also allows
visualization of the angle structures. The scleral spur is
an important landmark that is identified as the anterior-

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DJO Vol. 32, No. 2, October-December 2021

Figure 3: Angle structures as seen on UBM. SS-scleral spur, T-trabaecular Figure 6: UBM picture demonstrating post traumatic angle recession.
meshwork, AR-Angle Recess, I- iris

Figure 7: Plateau iris configuration as seen in UBM.

Figure 4: UBM showing increased iridotrabecular contact.

Figure 5: Posterior bowing of iris in PDS as seen on UBM. Figure 8: UBM showing ciliary body cyst leading to pseudo-plateau iris.

most point of the demarcation line between the ciliary rotation of the ciliary body causes peripheral iris
body and sclera, visualized on a longitudinal scan across elevation with secondary angle-closure (Figure 7).
the limbus (Figure 3). UBM differentiates the condition from pseudo-plateau
UBM can be used to find the mechanism of angle-closure iris, where the anterior displacement of peripheral
glaucoma including pupillary block, plateau iris, and iris is caused by cysts of iris and/or ciliary body
lens-induced. neuroepithelium (Figure 8).
• In the pupillary block, increased irido-trabecular contact • UBM can be used post-operatively to demonstrate the
is visible(Figure 4). patency of sclerostomy and the functionality of bleb.
• In pigment dispersion syndrome (PDS), posterior
bowing of iris along with the reverse pupillary block can Parameters of UBM in glaucoma.4
be demonstrated.(Figure 5). • Central anterior chamber depth (cACD): measured
• In plateau iris syndrome, no change in the configuration
of the iris occurs after peripheral iridotomy. Anterior between the anterior surface of the lens and the corneal
endothelium along the central axis

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DJO Vol. 32, No. 2, October-December 2021

Figure 9: UBM picture showing avulsion (arrow) of the ciliary body from scleral Figure 10: UBM showing tumor of the iris and the ciliary body
spur (SS)ant the connection between the anterior chamber and supraciliary
posterior lens capsule and zonular apparatus as AS-OCT is
space-cyclodialysis cleft (triangle). unable to view the same due to lack of penetration of infra
red rays for structures deeper to the pigmented epithelium
• Anterior chamber area (ACA): It is the area surrounded of iris.
by the anterior surface of the iris and the endothelial • Posterior capsule status: This is viewed using a 35MHz
surface of the cornea
probe. UBM is a useful tool in cases of suspected polar
• Angle Opening Distance at 500µm (AOD500): It is cataracts and post-traumatic total cataracts where the
calculated as the perpendicular distance from the status of posterior capsule is not known.
trabecular network at 500µm anterior to the scleral spur • Zonules: In the case of phacodonesis, UBM can determine
to the anterior iris surface. AOD at 500 microns was the status of the zonular apparatus , can show the area of
reported to be 347 ± 181 microns in normal eyes.3 zonular loss, laxity of zonules, or material depositions of
pseudoexfoliation syndrome.
• Angle Opening Distance at 750µm (AOD750): It is • Subluxation of lens: UBM allows us to get a dynamic
calculated as the perpendicular distance from the assessment of the degree of subluxation in supine position
trabecular network at 750µm anterior to the scleral spur which is critical in deciding the management.
to the anterior iris surface. • IOL status: The optic and haptic locations can be
ascertained using UBM post-surgery and in patients with
• Trabecular Iris Surface Area at 500µm (TISA500): dislocated IOL.
It is the trapezoidal area bounded anteriorly by
AOD500, posteriorly by a line drawn from scleral spur IRIS AND CILIARY BODY
perpendicular to the plane of the inner scleral wall to the In Aniridia, residual iris stump can be demonstrated
opposing iris, superiorly by the inner corneoscleral wall on UBM though gonioscopy is the modality of choice.
and inferiorly by the anterior iris surface. However, UBM can be of advantage in cases where corneal
clarity is hampered. Another important finding is iris and
• Trabecular Iris Surface Area at 750 µm (TISA750): ciliary body hypoplasia.
It is the trapezoidal area bounded anteriorly by • UBM helps in differentiating various types of iris and
AOD750, posteriorly by a line drawn from scleral spur
perpendicular to the plane of the inner scleral wall to the ciliary body tumors based on the echogenicity, depth
opposing iris, superiorly by the inner corneoscleral wall of involvement, and involvement of adjacent structures
and inferiorly by the anterior iris surface. (Fig.10).UBM can also be used to assess the growth or
regression of tumors on follow-up visits.
• Angle Recess Area at 750 µm (ARA750): It is defined • UBM helps in studying the ciliary body and pars plana
as the triangular area, the base of which is formed by in case of uveitis for any evidence of edema, thickening,
AOD750, the apex is formed by angle recess and the atrophy of the ciliary processes, cyclitic membrane, pars
sides of the triangle are formed by anterior iris surface plana exudates, and membranes.
and inner corneoscleral wall. • In a case of trauma, UBM can be useful in the demonstration
of cyclodialysis cleft (Figure 9), iridodialysis, angle
• Trabecular-ciliary process distance (TCPD): It recession (Figure 6)
is measured on a line extending from the corneal
endothelium at 500 µm from the scleral spur passing UBM VS AS-OCT5
perpendicularly through the iris to the ciliary process.
AS-OCT is a newly evolved technique, used for imaging
• Iris-ciliary process distance (ILCD): It is the distance of anterior segment of the eye. Compared to AS-OCT, the
measured from the posterior surface of the iris to the main strength of UBM is its ability to visualize structures
ciliary process along the same line as TCPD. behind the iris, including the ciliary body and lens as

• Lens vault (LV): It is the maximum perpendicular
distance from a horizontal line between the two scleral
spurs to the anterior surface of the lens.

LENS AND ZONULAR APPARATUS
UBM is an important modality for viewing the anterior and

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DJO Vol. 32, No. 2, October-December 2021

Table 1: Difference between UBM and AS-OCT

UBM AS-OCT

Principle Based on high-frequency ultrasound waves Based on low-interference interferometry
Method
Patient position Contact scanning Non-contact scanning
Coupling medium Supine position Sitting position
Time
Advantages Requires a silicone eye cup holding a coupling media No coupling media required

Disadvantages Time-consuming Quicker
Visualization of the structures behind the iris.
Near‐perfect tool for filtering blebs.
Risky in open globe injury, recent post-operative Higher axial resolution
period. Easy in uncooperative person

Structures behind the iris not visualised clearly.

the infrared rays, cannot penetrate the pigmented uveal Cite This Article as: Shweta Viswanath, Shikha Gupta,
tissue. Disadvantages compared to AS-OCT include the UBM Imaging Delhi J Ophthalmol 2021; 32 (2): 82 - 85.
need for a water-bath immersion with direct contact to Acknowledgments: Pictures Credits to Dr. Shikha Gupta
the eye, longer image acquisition times, and the need for Conflict of interest: None declared
an experienced operator (Table 1). Source of Funding: None
Date of Submission: 16 June 2021
3D- UBM Imaging System- An emerging modality.6 Date of Acceptance: 24 Nov 2021

3D-UBM allows for visualization of anterior segment Address for correspondence
structures with a 3D anatomical context. It provides detailed Shweta Viswanath Senior Resident
visualization and quantification of structures which allows
for better diagnosis, treatment planning, and assessment as Department of Ophthalmology, Guru
compared to conventional 2D UBM Nanak Eye Centre, New Delhi, India.
E-mail: shwetaviswanath0@gmail.
Conclusion com

Despite the emergence of newer modalities like AS-OCT
which have the advantage of being non-contact and quicker,
UBM remains superior for visualization of the ciliary body,
lens, and zonules.

References Quick Response Code

1. Kumar RS, Sudhakaran S, and Aung T. Imaging. From Pearls of
Glaucoma Management. 2016.

2. He M, Wang D, Jiang Y. Overview of Ultrasound Biomicroscopy.
J Curr Glaucoma Pract. 2012;6(1):25-53.

3. Conway RM, Chew T, Golchet P, Desai K, Lin S, O’Brien J.
Ultrasound biomicroscopy: role in diagnosis and management
in 130 consecutive patients. evaluated for anterior segment
tumors. Br J Ophthalmol 2005;89:950–955.

4. Pavlin CJ, Harasiewicz K, Foster FS. Ultrasound biomicroscopy
of anterior segment structures in normal and glaucomatous
eyes. Am J Ophthalmol. 1992 Apr 15;113(4):381-9.

5. Krema H, Santiago RA, Gonzalez JE, Pavlin CJ. Spectral-domain
optical coherence tomography versus ultrasound biomicroscopy
for imaging of non-pigmented iris tumors. Am J Ophthalmol.
2013;156:806–812.

6. Helms RW, Minhaz AT, Wilson DL, Örge FH. Clinical 3D Imaging
of the Anterior Segment With Ultrasound Biomicroscopy. Transl
Vis Sci Technol. 2021;10(3):11.

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DJO Vol. 32, No. 2, October-December 2021

Theme article

OCT Angiography: A promising tool in Glaucoma

Priya Saraf, Neha Sachdeva, Hage Amung
Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, India.

Abstract Optical Coherence Tomography Angiography, a non-invasive imaging modality provides a quantitative assessment
of microcirculation of retina and choroid in various layers. It is based on split spectrum amplitude decorrelation
algorithm (SSADA) which detects moving red blood cells and eliminates other noise (information). This review
provides a comprehensive summary on relevance, uses and limitations of Optical Coherence Tomography
Angiography (OCTA) in glaucoma.

Delhi J Ophthalmol 2021; 32; 86-89; Doi http://dx.doi.org/10.7869/djo.726

Keywords: OCTA, Glaucoma, SSADA, Vessel density, Flow index, Microvascular dropouts, Radial peripapillary slab, Choroidal slab

Introduction (MvD): Complete loss of chorio-capillaries in localized

Optical Coherence Tomography Angiography, a non- regions of parapapillary atrophy.

invasive imaging modality detects blood flow through Plexus involved in Glaucoma
the motion contrast generated by erythrocytes (RBC). It
provides a quantitative assessment of microcirculation of In current generations available, OCTA can scan both optic
the retina and choroid in various layers. disc region and macula.

Principle • Optic disc scan: Volumetric scan 4.5 x 4.5 mm2
centered around optic disc. It is divided into several slabs
OCTA uses laser light reflectance of surface of moving red of which Radial Peripapillary Capillary slab (RPC) and
blood cells to accurately depict vessels through different Choroidal Slab (CS) are useful in glaucoma.
segmented areas of the eye.1 The scan consists of multiple

individual A-scans, compiled into a B-scan to produce cross- RPC slab delineates vessels within the RNFL layer

sectional structural information. Same tissue area is imaged and extends from internal limiting membrane to posterior

multiple times, and differences are analyzed between scans boundary of RNFL.10 Reduction in vasculature is found more

(over time), thus permitting detection of zones containing in this slab compared to deep retinal slabs in glaucoma.

high flow rates (with marked changes between scans) and Choroidal slab delineates choroidal vessels in
zones with slower/ no flow (similar among scans).2 parapapillary region and extends from 75 µm below RPE in
RTVue –XR SDOCT or 65 µm below RPE in Cirrus HDOCT9,11
OCTA Algorithms This slab assesses deep retinal and choroidal vasculature.

Various commercially available OCTA devices incorporate

several algorithms to interpret variances in OCT signal. • Macular scan: It uses a 3x3 or 6x6 mm2 area of

• Split spectrum amplitude decorrelation macula, the latter having better glaucoma diagnostic ability.
angiography (SSADA) in Angiovue, RTVue-XR SD-OCT, Macular scan is divided into slabs, of which superficial slab
Optovue Inc, Fremont, CA, uses variation in intensity of picks up more reduction in vasculature compared to deeper
OCT signal to identify blood vessels.3,4 slabs in glaucoma.12

• Full spectrum amplitude decorrelation angiography Superficial slab: Extends from 3 µm below ILM to 15 µm
(FS-ADA) in Spectralis OCT2 Module, Heidelberg below inner plexiform layer in RTVue –XR SDOCT or from
Engineering, Heidelberg, Germany, uses variation in entire ILM to IPL in Cirrus HDOCT. 9,11

intensity spectrum of OCT signal to identify blood vessels.5

• OCT Ratio analysis (OCTARA) in DRI OCT Triton,
Topcon, Japan) uses full spectrum of OCT signal for blood
vessel delineation, thereby preserving axial resolution.6

• Optical microangiography OCTA algorithm Figure 1: OCTA images. a) Radial peripapillary capillary (RPC) network.
(OMAG) in Angioplex, Cirrus HD-OCT, Carl Zeiss Meditec b) Superficial Radial vascular network in the macular region (Source: Akman A
Inc., Dublin, CA, uses variation in intensity as well as phase et al. Optical coherence tomography in glaucoma: A practical guide.Springer,
difference of OCT signals for vessel delineation.7-9
2018: p.351)
OCTA Scans and Parameters

Quantification is done using various parameters3
• Vessel density: Ratio of area occupied by vessels divided

by total measured area.

• Flow index: Average decorrelation value in SSADA
algorithm.

• Parapapillary deep-layer microvascular dropout

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DJO Vol. 32, No. 2, October-December 2021

Deeper slab: Extends from 15 µm below inner plexiform distributed reduction of vessels.
layer to 30 µm below retinal pigment epithelium reference • Pseudo-exfoliation glaucoma: Studies have
line in RTVue –XR SDOCT or from IPL to RPE in Cirrus reported greater reduction of vessel densities compared to
HDOCT.9,11 POAG eyes of similar disease severity.25,26
• High Myopia: For glaucoma in high myopia29 visual
Relevance of OCTA in Glaucoma field is often difficult to interpret. Shin JW et al proved OCTA
to be better in linking these field parameters compared to
Functional damage in glaucoma is assessed by visual field OCT thickness. Microvasculature dropout in peripapillary
testing and structural damage by thinning of retinal ganglion choroid in high myopia eyes by OCTA aids in diagnosis,
cell layer and retinal nerve fiber layer by optical coherence where segmentation errors make retinal nerve fiber layer
tomography. Ocular coherence tomography provides thickness measures unreliable by conventional OCT.37
objective information on retinal layers’ thickness, with a • Advanced glaucoma: Visual field indices show a
high repeatability and reproducibility and has been in use higher concordance with OCTA than with OCT.30 This could
both for pre-perimetric disease and diagnose progression in be due to less pronounced floor effect seen in OCTA.31 Radial
advanced glaucoma. 13 peripapillary capillary slab, has been found to be the better
biomarker in advanced disease.32
The limitations in OCT in advanced glaucoma come from
the floor effect where OCT parameters reach a base, beyond Figure 2: Representative vascular, structural images of two eyes with mild-to-
which little change is visible with increasing severity of moderate and severe glaucomatous damage. a) Glaucomatous eye with mild
glaucoma.14 This effect is delayed for OCTA where vessel neuroretinal rim loss, localized vascular drop-out of RPCs (yellow and green
density eventually reaches the floor, for very advanced arrowheads), enlargement of foveal avascular zone FAZ and peripapillary
disease. Thus, OCTA detects changes in advanced glaucoma retinal nerve fiber layer thinning. b) Glaucomatous eye with advanced
which are invisible to OCT. cupping, widespread vascular drop-out of the RPC and macular region,
irregular, enlarged FAZ and diffuse pRNFL loss (Source: Akman A et al. Optical
Early pre-perimetric disease also can be picked up earlier coherence tomography in glaucoma: A practical guide. Springer,2018: p.352)
than structural OCT, with emphasis on early vascular
changes.40,41

• Primary open angle glaucoma (POAG): Reduced
flow index and vessel density within both Optic nerve
head slab and in peripapillary region (RPC slab) have
been demonstrated in eyes with POAG compared with
normal. 3,15 Reduced vessel densities in superficial macular
regions also have been reported with more pronounced
decrease correlated with severity of disease.12,16 Choroidal
slab documents deep-layer microvascular dropout in
glaucomatous eyes.17,18

Vascular derangement by OCTA has been confirmed by
reporting negative correlation of foveal avascular zone with
inner retinal layer thickness and visual field indices .38

Normal tension glaucoma (NTG): OCTA parameters
are lower with significant correlation with both OCT and
visual field indices primarily with mean deviation.19,20 This
finding however is not corroborated by other studies.20,21 The
technology is being used to evaluate early macular circulation
in open angle glaucoma, normal tension glaucoma and ocular
hypertension (OHT). Impaired vasculature before significant
disease has been demonstrated in both OAG and NTG with
lower superficial vessel density than control normal.36 Vessel
loss differences have been identified with lower deep vessel
density in NTG group compared to controls and larger FAZ
compared to OHT group.36

Primary angle closure glaucoma (PACG): OCTA
measurements are reduced in PACG eyes especially after
acute episode of angle closure.14,22,23 Mean vessel density has
been found to be less in PACG eyes compared to severity
matched POAG eyes.24 Inferior temporal peripapillary
vessel density loss has been identified to be more in POAG
eyes than PACG eyes despite similar vision and intraocular
pressure.39 Angle closure eyes document more evenly

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• Post trabeculectomy surgery: Confirming optic nerve head in human subjects. J Biomed Opt 2012;17:116018
the vascular theory, OCTA documented almost 60% 9. Rosenfeld PJ, Durbin MK, Roisman L, Zheng F, Miller A, Robbins
improvement in peripapillary retinal microvascular post
filtering surgery in POAG along with reduction in lamina G et al. ZEISS AngioplexTM Spectral Domain Optical Coherence
cribrosa depth.27 Tomography Angiography: Technical Aspects. Dev Ophthalmol
• Anterior segment OCTA: AS-OCTA images are 2016;56:18–29
found useful for objective assessment of conjunctival 10. Liu L, Edmunds B, Takusagawa HL, Tehrani S, Lombardi LH,
hyperemia and aid in understanding pathophysiology of Morrison JC et al. Projection-Resolved Optical Coherence
post-trabecular aqueous humour outflow.28 Tomography Angiography of the Peripapillary Retina in
Glaucoma. Am J Ophthalmol 2019;207:99–109
Limitations 11. Huang D, Jia Y, Gao SS, Lumbroso B, Rispoli M. Optical
Coherence Tomography Angiography Using the Optovue
• Motion artifacts: OCTA detects RBC movements Device. Dev Ophthalmol 2016;56:6–12
to generate contrast. Being extremely motion sensitive, the 12. Takusagawa HL, Liu L, Ma KN, Jia Y, Gao SS, Zhang M,
technology is prone to motion artifacts with movements like et al. Projection-Resolved Optical Coherence Tomography
heartbeats, respirations, saccadic eye movements, blinking Angiography of Macular Retinal Circulation in Glaucoma.
causing errors.33,34,14 Increasing scanning speed, decreasing Ophthalmology 2017;124:1589–99
image area and eye tracking technology are being used to 13. Shin JW, Lee J, Kwon J, Choi J, Kook MS: Regional vascular
reduce these. density-visual field sensitivity relationship in glaucoma
according to disease severity. Br J Ophthalmol 2017; 101: 1666–
• Shadowing/ masking effect: Signal attenuation 1672.
may occur due to media opacities like cataract, hemorrhages, 14. Rao HL, Pradhan ZS, Weinreb RN, Riyazuddin M, Dasari S,
PVD, PED creating false negative OCTA flow pattern. Venugopal JP, et al: Vessel density and structural measurements
of optical coherence tomography in primary angle closure
• Projection artifacts: It is caused by superficial and primary angle closure glaucoma. Am J Ophthalmol.
vessel signal projecting onto deep retinal and choroidal 2017;177:106-115
circulation, affecting detection of microvascular dropouts 15. Jia Y, Wei E, Wang X, Zhang X, Morrison JC, Parikh M et al.
(MvD).4,35 Newer generation OCTA like projection resolved Optical coherence tomography angiography of optic disc
OCTA reduce this. perfusion in glaucoma. Ophthalmology 2014;121:1322–32
16. Liu L, Jia Y, Takusagawa HL, Pechauer AD, Edmunds B,
Conclusion Lombardi L et al. Optical Coherence Tomography Angiography
of the Peripapillary Retina in Glaucoma. JAMA Ophthalmol
OCTA is a promising tool for diagnosing and monitoring 2015;133:1045–52
glaucoma patients, especially in situations where OCT 17. Suh MH, Zangwill LM, Manalastas PI, Belghith A,
has limitations like advanced disease and myopia. The Yarmohammadi A, Medeiros FA et al. Deep Retinal Layer
technology has corroborated vascular etiology of glaucoma Microvasculature Dropout Detected by the Optical Coherence
and would be useful to identify effect of treatment on retinal Tomography Angiography in Glaucoma. Ophthalmology
blood flow parameters. 2016;123:2509–18
18. Lee EJ, Kim TW, Lee SH, Kim JA. Underlying Microstructure
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(Phila) 2018;7:84–9 Cite This Article as: Priya Saraf, Neha Sachdeva, Hage
26. Park JH, Yoo C, Girard MJA, Mari JM, Kim YY. Peripapillary Amung OCT Angiography: A promising tool in Glaucoma
Delhi J Ophthalmol 2021; 32 (2): 86 - 89.
Vessel Density in Glaucomatous Eyes: Comparison Between Acknowledgments: Nil
Pseudoexfoliation Glaucoma and Primary Open-angle Conflict of interest: None declared
Glaucoma. J Glaucoma 2018;27:1009–16 Source of Funding: None
27. Shin JW, Sung KR, Uhm KB, Jo J, Moon Y, Song MK et al. Date of Submission: 1 Oct 2021
Peripapillary Microvascular Improvement & Lamina Cribrosa Date of Acceptance: 25 Dec 2021
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Optic Disc and Macular Vessel Density Measured by Optical
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587.

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Theme Article

Interpretation of Retinal OCT

Khushboo Chawla
Department of Ophthalmology, Guru Nanak Eye Centre, New Delhi, India.

Abstract With the recent advances in ophthalmic imaging, optical coherence tomography (OCT) has emerged as a non-
invasive, very useful, and sensitive tool to produce high-resolution, cross-sectional images of the macula and the
optic nerve head. OCT has been well absorbed in the clinical practice where it has been used to assess the different
layers of the retina and to some extent choroid in the newer machines. This article helps us to understand the step-
by-step interpretation of OCT in various macular and retinal pathologies, its diagnosis, follow-up, and management.

Delhi J Ophthalmol 2021; 32; 90-96; Doi http://dx.doi.org/10.7869/djo.727

Keywords: OCT, Interferometry, Multimodal Imaging, Retina, Cross-Sectional Imaging

Introduction

OCT has advanced rapidly over a course of a few years.

Based on the principle of laser interferometry. The retinal

morphology is reconstructed by images captured using the

reflected/backscattered light from the different retinal layers

(Figure 1). Qualitative and quantitative assessment of the 10

histological layers of the retina seen in different color codes

on the OCT map.

Evidence-based medicine requires recording all lth findings

until the finest details possible as clinicians, including OCT

analysis. Interpretation

Reading an OCT scan includes (Table 1):

• Qualitative analysis- retinal maps in 2-D, and 3-D

• Quantitative analysis: retinal thickness, map, and

volume

• Evaluation of findings, and with clinical correlation,

fluorescein, and indocyanine green angiography where Figure 2: Concave contour of the retinal layers as in posterior staphyloma.
ever necessary.1 Source: Handbook of retinal OCT [4]

QUALITATIVE ASSESSMENT

I) MORPHOLOGY
A. DEFORMATION OF ENTIRE RETINA

1. Concavity: In High myopes with longer axial length
and posterior staphyloma, OCT will show a marked
concavity (Figure 2). 1

Figure 1: Normal retinal anatomy and the International nomenclature of Figure 3: Convex morphology of the retinal layers seen in a choroidal tumor.
OCT (INOCT) as seen in SD-OCT. Source- Khurana R. New SD-OCT terms
proposed, 2014. B. ABNORMAL RETINAL PROFILE:
Thenormalfovealcontourisaregular,symmetricaldepression
2. Convexity: A convex contour of the retinal OCT map with alternating hyper reflective and hyporeflective layer
may be see in serous detachment of the RPE, sometimes
a lesser convexity in subretinal cysts, (Figure 3). arrangement. OCT can detect abnormalities, such as:
Subretinal tumors (eg. Melanomas) all the retinal layers •Vitreomacular traction(VMT): Deformation of the normal
including the RPE may appear raised so that it becomes
difficult to differentiate the type of tumor.1 foveal contour associated with the formation of fissures
or holes.
•Diffuse retinal edema: Reduced or altered foveal
depression due to retinal edema. Retinal profile may
become flat or irregular.
•Complex vitreoretinal traction
•Macular pucker and Retinal folds: Traction due to
epiretinal memberane (ERM) may cause distortion and
pucker. 2

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Table 1: The sequence of the Interpretation of OCT- Qualitative and Deeper lesions include Posterior retinal morphology, RPE,
Quantitative assessment. and External nuclear layer (ENL). The ENL reflects health
of the photoreceptors. The IS/OS junction and external
II) ANOMALOUS STRUCTURES 3 segments of photoreceptors are important.
A. PRERETINAL/ EPIRETINAL IS/OS JUNCTION POSSIBLE OCT MORPHOLOGIES can be

a. Vitreoretinal interface abnormality, b. Epiretinal/ vitreal • Linear (Normal) •Deformed• thickened • Broken
membrane
III) REFLECTIVITY
B. INTRARETINAL The rays reflected from the retinal tissue may be seen of
a. Superficial retinal
i. Exudates- lipoprotein deposits at the junction of normal varied reflectivity. These signal strengths may depend
on factors such as:
and edematous retina • Light when it strikes a particular layer, having been
ii. Cotton-wool spots- Indistinct borders of hyperreflectivity partially absorbed by intervening tissues- quantity
absorbed and reflected.
suggestive of retinal nerve fibre layer (RNFL) infarcts • Reflected light reaching the detector after having been
iii. Hemorrhages reabsorbed from horizontal anatomical structures
b. Intra-retinal
i. Hemorrhages- Hyperreflective with shadows on The pathologies detected by varied reflectivities: 2
A. VERY HIGH
posterior layers. • Pigment • RPE Hypertrophy • Choroidal nevus • Scar
ii. Hard exudates- Hyperreflective lesions seen in DR,
tissue
hypertensive retinopathy, Coats disease, telangiectasias
and radiation retinopathy. B. HIGH
iii. Retinal fibrosis- Hyperreflective lesions with distortion • RNFL (normal) • IS/OS junction (normal) • RPE/
of the layers
iv. Disciform degenerative scars choriocapillaris complex (normal) • External segments
c. Intra-retinal fluid collections: of photoreceptors • External limiting membrane •
i. Retinal edema Hemorrhage • NVM • Hard exudate
ii. Focal and diffuse edema
iii. Serous retinal detachment (RD) C. MODERATE
d. Deeper retinal lesions • Outer and Inner Plexiform layer (OPL,IPL) (normal) •
i. Drusen- undulations in the RPE-choriocapillary
membranes Retinal edema
ii. RPE hyperplasia,
iii. Intraretinal and subretinal neovascular membrane D. LOW
(NVM), • Nuclear layer (normal) • Fluid collection: cavity, cyst,
iv. scarring following choroiditis,
v. trauma or laser atrophic scars, and detachment
vi. Hyper-pigmented choroidal nevus.
C. SUBRETINAL E. SHADOWING EFFECT
a. Sub-retinal fluid collections a. Anterior
i. Serous RD i. Hemorrhage, Exudates and
ii. CNVM ii. blood vessels (normal)
a. Occult (Type I) b. Classic (Type II) c. RAP (Type III) b. Posterior
i. Thick RPE, Pigments, CNVM, Scarred tissue

Table 2: Normal layers of Retinochoroidal layers according to the
International nomenclature of OCT as seen on SD-OCT. Source-
Khurana R. New SD-OCT terms proposed, 2014.Quantitative
assessment.

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Figure 4: Color coding of the retinal layers: High Reflectivity-Red-RNFL and Figure 5: OCT showing Vitreomacular traction at the macula resulting in
IS/OS junction(white arrow); Medium reflectivity- green-Plexiform layer and distortion of foveal contour and intra retinal edema. Source: Guru Nanak Eye
Centre, New DelhiLow reflectivity- black/blue-nuclear layers(Blue arrow).
Low reflectivity- black/blue-nuclear layers(Blue arrow).
6. Focal choroidal excavation: Localized choroidal
Quantitative Analysis concavity with normal overlying retina and scleral
integrity. Photoreceptor integrity indicates prognosis. 11
Quantitative assessment helps in evaluating the natural
course of the disease, the severity of the condition, follow up Limitations Of OCT
and response to therapy.
Color-coding used to describe the thickness on retinal map • Difficult to interpret the laterality of the eye from the
are 2 White: >450 micron, Red: 350 to 450µ, Orange: 320 to scan map.
350, Yellow: 270 to 320µ, Green: 170 to 250µ, Blue: <170µ.
(figure 4) • Clarity of the scan depends on patient and technical
factors such as cooperation of the patient, eye
Artifacts: movements, focusing on the target, age group and media
1. M i r r o r imaging- A partial or completely inverted clarity (cataract, vitreous opacities, corneal opacities)

image. Arises when the area to be examined crosses zero Figure 6: Full thickness macular hole with few intraretinal cystoid spaces.
line while acquisition. Seen in high myopes or when the
focus is too near to the eye. Figure 7: Diagrammatic description of the macular hole indices parameters
2. Vignetting- The iris may block the OCT beam calculated by OCT. Source: Sana I. Tinwala, optical Coherence Tomography:
3. Misalignment- It may lead to poor scan acquisition due
to poor/eccentric fixation of the patient. Essential Tool in Macular hole Managment. 2018
4. Blink artifact: Partial loss of scan image due to
momentary eye blinking Clinical Application
5. Motion artifact: distortion of the scan due to fine ocular Vitreomacular Interface Syndrome
movements
6. Out of range: the scan may be cut off when the focus is Includes VMT, macular hole, ERM, and cystoid macular
too close or too far from the eye. This error results when edema (CME)
the b-scan shifts vertically out of range. VMT: Various changes in the retina including cystic and
schitic changes, are defined as split in between ONL-OPL,
Newer OCT Biomarkers ERM formation and traction RD (Figure 5)

1. Subretinal hyperreflective membrane- Newer term for
hyper reflective collection in the sub retinal layer or
between neurosensory -RPE. It may constitute fibrin,
hemorrhages, exudates, etc. It is a biomarker seen in
neovascular age-related macular degeneration (nAMD)

2. Disorganization of retinal inner layer (DRIL) - The OCT
biomarker, indicating retinal stress and poor prognosis.
Inner layers of the retina including ganglion cell layer,
IPL, INL, and OPL become indistinguishable due to
distortion of boundaries as in macular edema.

3. Outer retinal tubulations (ORT): Irregularly arranged
cystic spaces at macula. These can be distinguished from
the cysts in edema by their hyper-reflective boundary.
Its presence indicates poor prognosis.

4. Leptochoroid- Thinning of the choroid
5. Pachychoroid- Dilated choroid vessels in Haller’s layer,

focal or diffused choroid thickness on SD-OCT.

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ERM: Highly reflective layer on the inner retinal surface- the foveola, leading to false appearance of true partial MH.
adherent or separate, partially or completely. It may distort A true lamellar hole is characterized by an absence of some
the foveal contour. retinal layers above the RPE, unlike a pseudohole where all
retinal layers are present above RPE.4
A completely detached ERM may be confused with detached Important features are:

posterior hyaloid due to hyperreflectivity of both. The 1. Presence of a hyperreflective ERM on either sides of
pseudo-hole.
posterior hyaloid is distinguished by a thin reflective layer
2. Second, well delineated, steep, punched out foveal
with a greater degree of separation from the retina compared contour.

to the denser reflection and less degree of separation of an 3. Verticalization of the foveal pit –straight and vertical
edges, as opposed to the rounded edges of an MH. This
ERM. The posterior hyaloid is adherent to ONH, unlike is almost pathognomonic for the condition

ERM.4 Macular Hole Myopia

Gass’ classification employs description in stepwise Posterior staphyloma
Posterior concavity of the posterior wall, including sclera,
formation of macular holes. However, recent international choroid and all retinal layers. The choroid is typically almost
imperceptible due to significant thinning.
vitreomacular traction study (IVTS) proposed classification
Myopic macular schisis or foveal schisis:
is based on OCT findings: Small (≤250 µm), medium OCT is critical step in diagnosis and followup to asses the
morphologic changes in myopic schisis. There is characteristic
(>250 µm and ≤400 µm), and large (>400 µm) (Figure 6).5 splitting of outer retinal layers, leaving a thicker inner
retina split. Joining these two layers are stretched muller
OCT has been playing a vital role in predicting the assessing cells which appear as perpendicular strands. Other changes
include thin choroid, prominent posterior hyaloid, ERM,
the severity, grading, and sequel after surgery.Various lamellar or FTMH. (Figure 8) 7

indices 6 used (Figure 7) are: Dome-shaped macula is a rare finding seen in some highly
myopic eyes. The reason is unidentified, but may be due
• The two forces acting on the retina: Anteroposterior to localized differentiation in scleral thickness. A small
or tangential: convexity of the macular area seen within the concavity of p
osterior staphyloma, accompanied by subretinal fluid seen
a.Diameter hole index (DHI)- Minimum diameter of the MH as hypo reflective space, in absence of other pathologies such
as CNV / CSCR.2
Maximal basal diameter
Myopic Tractional RD
This index denotes tangential traction at fovea and shows
that an equal base and inner diameter of MH has a greater A localized irregular elevation of the retina associated with
strength of traction over the retina. vitreous memberanes and traction seen at the macula in the
absence of any visible, peripheral retinal breaks. OCT shows
b. Tractional hole index (THI)- Maximal height of MH large neurosensory detachment at macula. 4, 7
Minimum diameter
Diabetic Macular Edema
Represents the anteroposterior VMT and/or retinal hydration
responsible for MH formation. Most common causes of vision loss seen in clinical practice.
• A few Indices taking into consideration both the forces on The main of DME are increased retinal thickness, intraretinal
retina are: spaces of reduced reflectivity, disintegration of the layered
retinal structure, and flattening of the central foveal
c. Hole forming factor (HFF)- Nasal arm length+ temporal arm length depression.

Maximal base diameter

d. Macular hole index (MHI)- Hole Height
Maximal basal diameter

Newer area indices are being studied: macular hole area
index (MAI), cystoid space area index (MCSAI) and tissue

area index (MTAI). 6

Pseudohole

A pseudo-hole, as opposed to MH, is a defect that appears
due to increased thickness of retinal layers on either sides of

Figure 8: Myopic macular schisis without macular hole.7 Figure 9: OCT of a case of Non proliferative diabetic retinopathy with CSME
showing neurosensory detachment at the macula with multiple cystic spaces
E-ISSN: 2454-2784  P-ISSN: 0972-0200 seen as hyporeflective cavities, hyper-reflective pinpoint suggestive of

hardexudates in the parafoveal area.

93 Delhi Journal of Ophthalmology

DJO Vol. 32, No. 2, October-December 2021

Figure 10: Dry AMD- Atrophy of the outer retinal layers and area of geographic has been reported that IS/OS junction and ELM status is
atrophy seen as an obliteration of outer retinal layers with shadowing.[4] positively correlated to the final recovery of visual acuity
after treatment.8
Figure 11: Classic CNVM showing RPE distruption.
Postoperative CME
Figure 12: Large PED with a cap of Subretinal fluid.
Large, hyperreflective cystic spaces located in the OPL.9
The classification given by Otani et al. (8) based on altered
retinal morphology: cystoid, spongy, and serous RD. Age-Related Macular Degeneration
Another classification proposed by Koleva Georgieva8 gives
interesting information about retinal thickness, retinal Drusens: characteristic OCT appearance is small elevations
morphology, retinal topography, macular traction, and ENL of RPE at the level of Bruch’s membrane.
and IS/OS status. Geographic atrophy: atrophy of the outer retinal layers and
Retinal thickness: No macular edema, subclinical and RPE, showing a reverse shadowing effect on OCT. (Figure
established macular edema 10)
Retinal morphology: includes
Histopathologically, described as changes between plasma
a. Spongiform edema membrane of RPE and basement membrane of RPE known
b. Cystoid edema as basal laminar deposits.
c. Tractional Another more common lesions, seen as hyperreflective
d. Serous macular detachment elevations between basement membrane of RPE and Bruch’s
e. Mixed edema membrane is called as basal liner deposits
Course of DME: It starts as focal edema progress to diffuse
edema. Non-resolving retinal edema leads to necrosis of Wet AMD:
the muller cell forming cystoid cavities, mainly the outer Lesions may be seen as an irregular pigment epithelial
retina (Henle’s fiber and OPL and occasionally IPL). It detachment (PED) with subretinal hemorrhage and fluid.
An irregularly shaped PED (Figure 12, 13) is in contrast to a
more smooth-shaped PED characteristic of CSCR.

CNVM characterized by an interruption in the linear RPE.
There are various key features of wet AMD that can be
uniquely identified based on their OCT appearance 9
• Classic CNVM: abnormal neovascular tissue

penetrating the RPE/Bruch’s membrane complex and is
present in the sub retinal space (Figure 11).
• Occult CNVM: is present when the abnormal
neovascular tissue remains under RPE
• RPE tear: Characteristic OCT appearance of sharply
demarcated region of absent RPE adjacent to an area of
bunched-up RPE.
• Disciform scar: a varied hyper-reflective subretinal scar
• Retinal angiomatous proliferation: rare cause of nAMD
resulting from abnormal neovascular tissue within the
deep retina that typically originates within the retina
and migrates towards the choriocapillaris and/or retinal
surface
• Polypoidal choroidal vasculopathy (PCV): PCV is
thought to be a variation of type 1, where polypoidal
abnormal vascular complexes are located underneath
the RPE. OCT shows highly elevated RPE or double
reflective layers that consist of RPE and another
hyperreflective layer below the RPE known as Double-
layer sign.

CSCR

Acute: OCT shows a well-circumscribed clear area
between the RPE and the neurosensory retina suggestive of
neurosensory retinal detachment (NSD). (Figure 14) Diffused
choroidal thickening in acute CSCR, better visualized with
EDI protocol on most commercial OCT scanners. This
thickening improves on resolution.

Chronic: Accumulation of hyper-reflective material in the
subretinal space. It may result in cystic retinal changes and
eventual retinal thinning, accompanied by photoreceptor
and RPE loss.

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DJO Vol. 32, No. 2, October-December 2021

Figure 13: Fibrous PED. Multifocal CSCR is characterized by multiple discrete NSD.10
OCT is indicated for quantitative monitoring of the subretinal
Figure 14: Smooth dome shaped neurosensory detachment suggestive of fluid.
central serous retinopathy..
Vascular Occlusions
Figure 15: OCT showing intraretinal layers schisis of outer nuclear layer seen
in CRVO. Branched Vein occlusion: Retinal edema localized to the
area drained by the obstructed vein. Diffused or cystic
Figure 16: Stargardt’s disease showing atrophy of the outer retinal layers, (hyporeflective spaces) with Hard exudates (hyperreflective
with hyperreflective flecks at the level of RPE and marked foveal thinning. intraretinal spots) and Subretinal fluid may be seen.

Central retinal vein occlusion: Similar to BRVO but diffuse
edema within the outer retinal layers. (Figure 15)

Retinal artery occlusion: Acute stage show hyperreflectivity
of inner retinal layers creating a shadowing effect over the
outer layer reflectivity. This occurs as the central retinal
artery supplies the inner layers (watershed zone – between
INL and OPL).
It is limited to the territory of the artery supplied in branch
occluded (in BRAO) and diffused (in CRAO). Thinning and
schitic changes are seen in the long term.4,10

Retinitis Pigmentosa

In advanced cases, there is marked atrophy and attenuation
of the Photoreceptor and outer retinal layers. Postoperative
CME may also be detected with OCT. 4

Macular Telangiectasias

Is a form of Coats disease and is developmental in etiology.
There are two types of MacTel:

• MacTel Type 1 being unilateral may be seen as CME
as in any other etiology.

• MacTel type 2: Varied appearance of irregular
lamellar defects within retinal layers, seen as hyporeflective
cavities associated with photoreceptor atrophy and outer
layer tissue loss. In chronic form, pigment deposition and
atrophy and rarely a secondary CNVM may develop.

Stargardt’s Disease

Small deep yellow flecks seen clinically are seen at the level
of RPE. It is associated with foveal and parafoveal atrophy
of the outer retinal layers. In later stages, it may progress to
geographical atrophy like pattern on OCT. (Figure 16)

Traumatic Commotio Retinae

Damage to the outer retinal layers seen as whitening
clinically may be seen as cleft like empty hypo reflective
space under the neurosensory retina due to IS/OS junction
and RPE digitation disruption.

Photothermal And Photomechanical Injury/ Laser
Injury

Occurs due to exposure to high power laser lights used in
military/research devices. Central macula is the commonly
involved area. It shows IS/OS-ellipsoid junction and RPE
disruption. It may involve Inner retinal layers too.

Photochemical Injury

Is due to welding arc or phototoxicity from the sun. Localized
it is single/multiple focal alteration in outer retinal layers
with IS/OS junction distortion seen, which leaves behind a
hypo reflective space (outer retinal hole). ELM and RPE may
be spared.

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DJO Vol. 32, No. 2, October-December 2021

Conclusion Cite This Article as: Khushboo Chawla, Interpretation Of
Retinal OCTDelhi J Ophthalmol 2021 32 (2) 90-96.
OCT has proven to be an important noncontact investigation Acknowledgments: Nil
for confirmation and decision making of various retinal Conflict of interest: None declared
pathologies. With higher resolutions and advances with Source of Funding: None
adaptive optics, knowing OCT interpretation becomes Date of Submission 12 Aug 2021
essential part of the learning curve for all ophthalmologists. Date of Acceptance: 25 Nov 2021

References Address for correspondence
Khushboo Chawla, MBBS, DNB
1. Lumbroso, B., & Rispoli, M. (2011). Guide to interpreting spectral
domain optical coherence tomography (1st ed., pp. 13). Dublin, Senior Resident Ophthalmology
CA: I.N.C. Innovation-News-Communication. Department of Ophthalmology, Guru
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DJO Vol. 32, No. 2, October-December 2021

Theme Article

Fundus Fluorescein Angiography

Priyadarshi Gupta, Ekta Shaw

Department of Ophthalmology, Guru Nanak eye centre, New Delhi, India.

Abstract Fundus fluorescein angiography (FFA) is one of the age-old methods to examine the retinal and choroidal vasculature
using dye namely sodium fluorescein. It involves administration of dye intravenously followed by serial fundus
photographs using FFA machine with barrier and excitation filters. This review article consists of the basic principles,
understanding, interpretation and salient features of FFA for various ocular pathologies.

Delhi J Ophthalmol 2021; 32; 97-101; Doi http://dx.doi.org/10.7869/djo.728

Keywords: Fundus Fluorescein Angiography, Ffa, Fluorescein, Imaging Modality

Introduction Table 1 shows differences between FFA and ICGA.

Herald Novotny and David Alvis, first discovered FFA ICGA
Fundus fluorescein angiography (FFA) and its role in
ophthalmology.1,2 FFA is one of the age-old methods to Uses Sodium fluorescein Uses Tricarbocyanine dye
examine retinal and choroidal vasculature using fluorescein. dye (376 Da) (Iodine based dye) (775 Da)

This review article consists of the basic principles,

understanding and interpretation of FFA for various ocular 80 % protein bound, 20 % free 98 % protein bound, 2 %
pathologies. free

Principle Excitation – 465-490 nm Excitation – 790 nm (infra red)
(blue) Emission – 840 nm
FFA is based on the principle of fluorescence. Luminescence
is emission of light from any source other than high Emission – 520-530 nm
temperature. Fluorescence is luminescence maintained by (yellow green)
continuous excitation. Fluorescent molecules have property
to emit light energy of longer wavelength when stimulated by Escapes chorio capillaries Does not escape chorio
a shorter wavelength. Phosphorescence is the luminescence (being smaller in size) capillaries (being larger in
where the emission continues long after the excitation is
stopped.3 FFA uses Sodium fluorescein as a dye to help Better for retinal vascular size)
image retinal and choroidal vasculature. Indocyanine green pathologies
angiography (ICGA) based on similar principle as FFA, uses Better for choroidal
tricarbocyanial dye and images choroidal vasculature. Table pathologies
1 elaborates on difference between FFA and ICGA.
blood supply and BRB
Fluorescein sodium is an orange red water-soluble dye,
moleular weight of 376 Da and pH of 8 - 9.8. Normal adult Indications of FFA
dose is- 500mg - 3ml of 20%, 5ml of 10% or 10 ml of 5%.
Paediatric dose is – 35mg/ 10 pounds of body weight. Oral • Diabetic retinopathy
dosage – 30 mg/ kg. pH – 8 to 9.8. 80% of molecules bind • Retinal vaso-occlusive diseases
to plasma proteins.It is metabolised by liver & eliminated • Age related macular degeneration
by kidney in 24-36 hrs. The dye absorbs light in blue range • Hypertensive retinopathy
of visible spectrum, peaking at 465-490nm and emits light • Choroidal Inflammatory disorders
in yellow-green range of visible spectrum, peaking at 520- • Ocular ischemic syndrome
530nm. A combination of excitation and barrier filters • Macular dystrophy
help image the vasculature as dye flows within arteries,
capillaries and veins. Contraindications of FFA

Absolute contraindication
• Allergic reaction in past.

For interpretation of FFA, knowledge of retinal and Relative contraindications
choroidal vasculature and the blood retinal barriers (BRB) is • Cardiac disease,
important. Retina receives blood supply from both choroidal • Renal impairment,
vasculature (outer four layers) and central retinal artery • Uncontrolled hypertension and
(Inner six layers).4 Retina has two BRBs: the inner BRB which • Pregnancy.
is constituted by tight junction between the endothelial cells • Allergy to iodine and seafood allergies are
of capillaries in outer plexiform and inner nuclear layer; and
the outer BRB which is formed by the tight junctions between not contraindications to FA – but are absolute
the RPE cells. Ocular pathologies like Diabetic retinopathy contraindications to ICGA as ICG contains iodine.
(DR), hypertensive retinopathy, vascular occlusions, central
serous chorioretinopathy (CSCR) lead to disruption in the Procedure

• The procedure is explained and formal consent is taken.
It is important to mention common adverse effects,

E-ISSN: 2454-2784  P-ISSN: 0972-0200 97 Delhi Journal of Ophthalmology

DJO Vol. 32, No. 2, October-December 2021

particularly invariable skin and urine staining and • Pruritis, urticaria
nausea immediately following fluorescein injection. • Bronchospasm, laryngeal edema, anaphylaxis
• Ensure adequate pupillary dilatation and clear media • Hypotension, syncope, myocardial infarction,
• Photographs of target eye are taken prer to injection cardiac arrest
of dye to detect pre injection fluorescence (Pseudo • Seizures – tonic clonic type.
fluoresecnce and auto fluorescence).
• Intravenous access to inject dye is through ante - cubital Phases of Normal FFA (Figure 1)
vein. The dye is injected in a span of about 4-6 sec and
timer in FFA machine is switched on. Rapid injection of A normal FFA consists of 6 named phases as the dye travels
dye is avoided as it is associated with a higher incidence through the choroidal and retinal vasculature. The arm to
of nausea. retina circulation time is 8-10 seconds
• Light is preferably switched off and the target eye is
imaged at the beginning and end of injection. Choroidal Flush (a)
• Subsequently, photographs are taken at intervals of 1.5- • Dye first appears in the choroid 10-12 seconds after the
2 seconds, upto 30 seconds. Photograph of fellow eye injection
is taken after 30 seconds. Thereafter, photographs are • Choriocapillaries are leaky and dye leaks into the
captured once in 1-2 minutes upto 10 minutes. extravascular space
• Photographs of posterior pole are captured initially and • Cilioretinal artery, seen in 20 % population, also fills
peripheral images are captured later. In case the area during this phase
of interest is in the periphery (e.g in Eale’s disease), • Both are supplied by short posterior ciliary arteries
peripheral images may be captured earlier.
Arterial Phase (b) (12-13s)
Adverse Reactions • Typically fills 1-2 seconds after choroid
• Followed by complete filling of retinal capillary bed
• Nausea (5%) & vomiting (0.3-0.4%)- usually seen 30-60s
after injection and lasts 2-3 minutes Arteriovenous Phase (c) (13-14s)
• In this phase the retinal arteries, capillaries and veins
• Extravasation of dye – transient yellowish discoloration contain fluorescein
of skin (cold compresses for 5-10 minutes usually settles • Complete filling of retinal capillary bed followed by
the discoloration).

• Inadvertent arterial injection

Figure 1: Phases of Normal FFA (a-Choroidal flush, b-Arterial phase, c-arteriovenous phase- note the laminar flow, d-Venous phase, e-Recirculation phase, f- Late
phase) (Source-retina image bank, Internet)

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