Stellate nonhereditary idiopathic foveomacular retinoschisis treated as cystoid macular edema

Brijesh Takkar; Mihika Dube; Prakhar Goyal; Ashwini Singh; Sunita Sabarwal

doi:10.4103/ijo.IJO_1569_20

CASE REPORT

Year : 2021 | Volume : 1 | Issue : 1 | Page : 121-122

Stellate nonhereditary idiopathic foveomacular retinoschisis treated as cystoid macular edema

Brijesh Takkar¹, Mihika Dube², Prakhar Goyal³, Ashwini Singh², Sunita Sabarwal²
¹ Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh; Smt. Kanuri Santhamma Center for Vitreoretinal Diseases; Center of Excellence for Rare Eye Diseases, L. V. Prasad Eye Institute, Hyderabad, Telangana, India
² Department of Ophthalmology, All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India
³ Smt. Kanuri Santhamma Center for Vitreoretinal Diseases, L. V. Prasad Eye Institute, Hyderabad, Telangana, India

Date of Submission	19-May-2020
Date of Acceptance	29-Aug-2020
Date of Web Publication	31-Dec-2020

Correspondence Address:
Dr. Brijesh Takkar
Smt. Kanuri Santhamma Center for Vitreoretinal Diseases, L. V. Prasad Eye Institute, Hyderabad - 500 034, Telangana
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijo.IJO_1569_20

Abstract

Stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) is a rare eye disease, hitherto unreported in Indians. We report a case of SNIFR in an Indian female wrongly treated as cystoid macular edema (CME). Differentiation between chronic CME and foveoschisis is paramount while dealing with rare diseases like SNIFR.

Keywords: Cystoid macular edema, idiopathic foveoschisis, stellate nonhereditary idiopathic foveomacular retinoschisis

How to cite this article:
Takkar B, Dube M, Goyal P, Singh A, Sabarwal S. Stellate nonhereditary idiopathic foveomacular retinoschisis treated as cystoid macular edema. Indian J Ophthalmol Case Rep 2021;1:121-2

How to cite this URL:
Takkar B, Dube M, Goyal P, Singh A, Sabarwal S. Stellate nonhereditary idiopathic foveomacular retinoschisis treated as cystoid macular edema. Indian J Ophthalmol Case Rep [serial online] 2021 [cited 2021 Feb 26];1:121-2. Available from: https://www.ijoreports.in/text.asp?2021/1/1/121/305492

Foveoschisis refers to splitting of the neural retinal layers. It can be associated with high myopia, X linked retinoschisis (XLR), vitreo-macular traction and epiretinal membrane, chornic macular edema, optic disc pit and enhanced S cone syndrome.^[1],[2] Diagnosis is confirmed by optical coherence tomography (OCT) which shows the characteristic splitting of retinal layers, with the absence of leakage on fluorescein angiography (FA). Stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) is a rare entity and according to Ober et al.,^[3] it typically involves single eye of young females. Cases of SNIFR don't have any identifiable cause for the macular pathology and there is no family history. The disease is characterized by typical OCT features which may be used for differentiating it from other etiologies of retinoschisis. Its usual non-progressive nature differentiates it from other causes of retinoschisis, though rare localized macular detachment is described.^[3] To our knowledge, SNIFR has not been reported in Indians.

We report a case of SNIFR in an Indian female. The case was misdiagnosed as chronic cystoid macular edema (CME) and suggested surgical procedure. We also discuss features useful for its differentiation from other causes of foveoschisis.

Case Report

A 49-year-old lady presented with complaints related to near vision loss and low vision in left eye (LE). She had been diagnosed to have a branch vein occlusion of the macula with macular edema, and also advised anti-vascular endothelial growth factor (VEGF) therapy. The duration of vision loss in LE was long but not known exactly. There was no family or systemic history. Her visual acuity was 20/20 in right eye (RE) and 20/100 in LE with mild myopia of -0.5 D. Ocular adnexa and anterior segments were within normal limits. Fundus examination revealed a normal RE, while in the LE there was a lesion resembling macular edema, but without signs of recent or chronic retinal vein occlusion. Peripheral retinal examination was within normal limits. OCT angiography (OCTA) of LE showed a well demarcated dark area in the deeper capillary plexus, corresponding to the schisis [Figure 1]. OCT showed schisis in the outer plexiform layer centrally, and also in the retinal nerve fibre layer inferior to the fovea and in the peripapillary region [Figure 2]. Mildly hypo-autofluorescent areas were noted corresponding to the area of the schisis [Figure 1]. Perimetry showed only a central scotoma involving the foveal area [Figure 1]. Right eye was within normal limits on imaging [Figure 3].

Figure 1: (a) Fundus picture of left eye with overlay showing the scanned area. (b) Composite OCT angiography shows centrally well demarcated dark area due to large schitic cavities. (c) En face OCT angiography with slab set at deep retinal layer showing centrally well demarcated dark area. (d) Short wave autofluorescence (AF) showing mildly hypo AF corresponding to schitic areas. (e) Late phase fluorescein angiography at 4 minutes showing absence of dye leakage. (f) 10 degrees standard perimetry of left eye showing central scotoma with normal peripheral macula

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Figure 2: Swept source OCT vertical (upper panel) and horizontal (lower panel) line scans showing stellate splitting of retinal layers beginning at the posterior border of the outer plexiform layer. Involvement of peripapillary superficial layers can also be seen nasal to the fovea. The bridging tissue is symmetrical and regularly placed across the fovea

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Figure 3: Fluorescein angiography and optical coherence tomography of right eye showing normal images

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The lady was suspected to have SNIFR in LE and was advised to undergo electroretinogram and genetic analysis for RS1 gene with a following course of topical dorzolamide therapy. Her son was evaluated for visual acuity and general fundus examination that were normal. She refused further evaluation and was only interested in the presbyopic correction as LE had low vision for a long time.

Discussion

Ober et al. described 22 eyes with SNIFR, which is the largest series of patients with this disease. Majority of the patients (70%) had involvement of one eye in that series, and 16/17 patients were female.^[3] The hallmark of schisis in SNIFR is a separation occurring at the posterior border of the outer plexiform layer in the central macula as seen in our case too.^[4] Though most conventional studies have reported only posterior findings and splitting of outer retina, a report with widefield OCT has shown that the schisis can involve peripheral macula and retina, and also cause splitting of inner retinal layers.^[3],[5] In our case, the inner layers were involved additionally in the peri-papillary area. Involvement of inner layers specifically in the peri-papillary area has also been documented in cases of SNIFR before.^[6],[7] SNIFR is generally considered not amenable to therapy, and vision loss can be progressive rarely.^[3] There is low-level evidence in support of topical dorzolamide for the management of SNIFR.^[8]

XLR is an important differential of SNIFR, but it is almost exclusively seen in males as the implicated RS1 gene is present on the X chromosome. Bilateral involvement is generally a rule in XLR, though asymmetry is well established. It manifests in females only in special situations like Turner syndrome (XO genotype) and in cases with known familial mutations.^[3],[9],[10] Our patient was a female and did not consent to a genetic analysis, but it is highly unlikely that she had XLR in one eye only, and that too without familial involvement. OCTA findings may prove useful for differentiation between SNIFR and XLR, but this requires a binarization software code. The dark area seen in OCTA is due to the large schitic cavities and is well known.^[4]

Apart from XLR and chronic CME, other diseases may also present as retinoschisis though the stellate pattern of splitting is highly unusual for them. Myopic tractional maculopathy can cause splits inside the neural macula at multiple levels but is always accompanied by evidence of high myopia. Epiretinal membranes and vitreoretinal traction can also lead to retinoschisis, though in most of these cases traction is a prominent feature on OCT and can be easily identified. Similarly, optic disc pit and advanced glaucomatous disorders should have other evident clinical and OCT signs. Enhanced cone syndrome should have bilateral affection with complaints of nyctalopia and characteristic pigmentary changes.

Conclusion

To summarize, this is the first report of SNIFR in India. SNIFR needs to be differentiated from other causes for accurate therapy.

Acknowledgements

Hyderabad Eye research foundation for research support.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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