Structured Abstract
Purpose
To present a case of stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) resolution associated with vitreomacular adherence (VMA) release and propose a potential contributing association between SNIFR and vitreomacular interactions.
Observations
A 67-year-old female patient was diagnosed and followed for SNIFR in OD with spectral-domain optical coherence tomography (SD-OCT) scans at presentation and subsequent visits at 3, 6, 16 and 22 months. VMA and foveomacular retinoschisis remained unchanged on SD-OCT during the first 6 months of the follow-up. At 16-month follow-up visit, SD-OCT revealed VMA release and an important improvement of the macular schisis. At 22 months of follow-up, SNIFR cavities completely resolved in the presence of posterior hyaloid separation from the macular area without any adjunct treatment. The authors could not identify any other possible cause to justify the resolution of SNIFR other than VMA release in this case. Patient did not undergo any treatment for OD other than phacoemulsification 3 months after initial visit.
Conclusion
The present case illustrates with SD-OCT scans a possible association between SNIFR resolution and VMA release, highlighting a potential tractional component of the posterior vitreous on the internal limiting membrane and consequent glial cells stretching with schisis formation.
Summary statement
Vitreomacular adhesion release may be associated to the anatomical resolution of stellate nonhereditary idiopathic foveomacular retinoschisis.
Ethics
Ethics Committee advice is not required for the routine medical care of patients.
Patient consent
Written consent to publish this case has not been obtained. This report does not contain any personal identifying information.
Introduction
Stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) was first described in 2014 by Ober et al. and its pathogenesis remains to be clarified. Previous reports suggested that macular retinoschisis could be associated to vitreous traction in eyes with fragile nerve fiber layer and that the stellate pattern observed in SNIFR could be associated with the lack of structural support provided by local blood vessels in the Henle fiber layer.
We report a case of SNIFR with spontaneous resolution after vitreomacular adherence (VMA) release.
Case report
A 67-year-old white woman was referred to Ophthalmology Department of Maisonneuve-Rosemont Hospital, University of Montreal (Montreal, QC, Canada) in March 2016 for foveomacular retinoschisis in OD and vitreomacular traction (VMT) syndrome in OS. She had a previous medical history remarkable for type 2 diabetes diagnosed 2 years before the referral, hypertension and hypothyroidism. Patient refraction was +4.50 in OD and +3.00 + 0.50 × 150° in OS. Best corrected visual acuity was 20/40 in OD and 20/25 in OS. Slit-lamp biomicroscopy revealed a grade 2 nuclear cataract in OD and mild nuclear sclerosis in OS. Fundus evaluation showed radial spoking around the fovea in OD and suspicion of VMT in OS. No signs of diabetic retinopathy were identified.
On SD-OCT scan, OD presented retinal splitting at the level of Henle fiber layer (HFL) with bridging tissue separating cystic spaces in the fovea and broad vitreomacular adhesion ( Fig. 1 A). HFL en face slab of OD evidenced the stellate appearance of the macula with alternating radial hyporeflective and hyperreflective areas ( Fig. 2 A). SD-OCT scan of OS confirmed the presence of VMT which was treated with combined phacoemulsification and pars plana vitrectomy during the follow-up ( Fig. 1 B, 1D, 1F, 1H and 1J).
The diagnosis of SNIFR was stablished after an extensive investigation and exclusion of other causes of foveomacular retinoschisis. The patient had no personal or familial risk factors for congenital juvenile X-linked retinoschisis (CXLR) and as such RS1 mutation was not investigated. Patient denied previous use of niacin or taxane derived drugs.
Three months after initial presentation the patient underwent routine phacoemulsification. Her post-operative BCVA improved to 20/25 in OD. Fundus examination and SD-OCT remained unchanged in OD ( Fig. 1 E) at her 6-months retina follow-up. No specific treatment for the SNIFR was recommended as visual acuity was satisfactory and patient was asymptomatic. Sixteen months after initial referral, VMA release and an important improvement of the macular schisis were observed ( Fig. 1 G). At 22-months follow-up, total resolution of SNIFR with the reabsorption of residual intraretinal fluid was detected in OD ( Fig. 1 I). BCVA remained at 20/25 in OU without metamorphopsia or other visual symptoms. Patient denied any other eye surgeries, use of carbonic anhydrase inhibitors or any other plausible cause to justify the schisis resolution in OD apart from observed VMA release.
Discussion
Ober et al. presented a series of 22 eyes from 17 patients with foveomacular retinoschisis without any known hereditary or acquired predisposition and described it as SNIFR. This condition was observed mainly in female (94%) and myopic (72%) patients with unilateral schisis (70%). Interestingly, 19 (86%) of the eyes presented with VMA. SNIFR diagnosis is based on the presence of characteristic radial spoking around the fovea and the splitting of the retina at the level of Henle fiber layer in OCT after the exclusion of other possible causes of retinoschisis. Such conditions include CXLR, myopia, optic disc pit, glaucoma, myotonic dystrophy, enhanced S-cone syndrome and vitreomacular traction.
Other findings in SNIFR include mild radial hypofluorescence in perifoveal region and absence of leakage/staining on fluorescein angiography. BCVA is usually 20/40 or better and metamorphopsia has also been described as a possible symptom.
In this case, other causes of macular retinoschisis were excluded. The presence of VMA associated with SNIFR in OD and VMT in OS may suggest that SNIFR could be an alternative presentation in patients with vitreomacular interface abnormalities. It is also possible that patients with SNIFR might present an underlying susceptibility for retinoschisis caused by normal vitreo-retinal interface adhesion which would not cause retinal splitting in patients without this condition. As visual acuity is usually preserved in SNIFR cases, invasive interventions to promote VMA release would rarely be warranted.
According to the International Vitreomacular Traction Study Group Classification of Vitreomacular Adhesion, Traction, and Macular Hole’s Group Classification, OD presented a broad VMA on SD-OCT. Interestingly, a clear spatial correlation of VMA and macular retinoschisis areas was observed ( Fig. 3 ).
