Target Audience: General Ophthalmologists
Source Article:American Journal of Ophthalmology Case Reports 42 (2026) 102551
Authors: Alexandre Bourdin, Isabelle Audo, Amine Benadji, Franck Fajnkuchen, Michel Paques, and Sarah Mrejen
Introduction & Clinical Context
Stellate Nonhereditary Idiopathic Foveomacular Retinoschisis (SNIFR) is a relatively recently described entity characterized by foveomacular splitting without an underlying genetic defect (such as X-linked retinoschisis) or significant secondary drivers like high pathologic myopia or optic disc pits. While SNIFR classically presents as localized maculopathy, extended variants involving the midperipheral retina (MPRS) and presenting with microvascular abnormalities pose diagnostic and management challenges. This case study provides a multimodal imaging overview of an extensive SNIFR variant with associated neovascular-like microvascular anomalies and an electronegative ERG pattern.
Key Clinical Case Presentation
- Patient: 44-year-old female presenting with non-specific ocular discomfort and preserved visual acuity (20/20 OU).
- Refraction: Moderate myopia (Axial length: 25.01 mm OD, 24.48 mm OS; SE: -5.75D OD, -4.75D OS) without staphyloma, lacquer cracks, or myopic chorioretinal atrophy.
- Fundus Exam: Bilateral extended retinoschisis with visible microvascular abnormalities along the vascular arcades.
Multimodal Imaging & Diagnostic Findings
| Diagnostic Modality | Findings & Structural Characteristics | Clinical Significance |
|---|---|---|
| Spectral-Domain & Widefield SS-OCT | Splitting at Henle’s Fiber Layer (HFL) in the macula; involvement of HFL, INL, GCL, and RNFL-ILM interface in the periphery. Incomplete PVD (stage 1) without vitreomacular traction. | Demonstrates widespread inner retinal layer splitting beyond the typical foveal locus. |
| OCT-Angiography (OCT-A) | Normal superficial and deep capillary plexi perfusion. Microvascular anomalies localized between the RNFL and ILM. | Identifies two morphological patterns: superficial/elongated along the ILM and deeper/tufted. |
| Fluorescein Angiography (FA) | Late leakage corresponding to the microvascular abnormalities, but no non-perfusion or ischemia. | Distinguishes this condition from ischemia-driven retinal neovascularization. |
| Full-Field ERG | Electronegative ERG under scotopic conditions with reduced b/a ratio under light-adapted conditions. | Points to inner retinal/post-photoreceptoral synaptic dysfunction. |
| Adaptive Optics (AO-FIO) | Hyperreflective foveal dots within the foveal avascular zone (FAZ). | Potential novel biomarkers representing cone/Müller cell dysfunction or synaptic transmission impairment. |
| Genetic Testing | Sanger sequencing of RS1 coding sequence was negative for pathogenic variants. | Excludes X-linked juvenile retinoschisis (XLRS). |
Pathophysiology: Mechanical Stretch vs. Ischemia
A pivotal finding in this case is the presence of neovascular-like vessels with active fluorescein leakage despite complete absence of capillary non-perfusion on OCT-A and FA.
- Stretch-Induced Angiogenesis: Rather than ischemic drive (VEGF release due to hypoxia), vessel stretching caused by severe inner retinal splitting triggers localized vascular proliferation.
- Extracellular Matrix Microenvironment:
- Within the fluid-filled schisis cavity, new vessels take on a globular/tufted morphology.
- Beneath the ILM, they assume an elongated shape.
- Absence of Preretinal Extension: Because ischemia is absent, these vessels do not breach the ILM into the cortical vitreous, significantly lowering the risk of vitreous hemorrhage or tractional retinal detachment.
Differential Diagnosis
- X-Linked Retinoschisis (XLRS): Differentiated by female sex, negative RS1 genetic testing, and lack of characteristic XLRS non-perfusion areas.
- Myopic Foveoschisis (MF): Lacks classic high-myopia markers (e.g., axial length > 26.5 mm, posterior staphyloma, or posterior hyaloid traction).
- Primary Peripheral Retinoschisis (PPR): MPRS can overlap with PPR, but SNIFR features prominent maculopathy and non-ischemic microvascular anomalies.
Clinical Management Key Takeaways
- Conservative Management is Safe: In the absence of ischemia, retinal neovascularization, or vitreous hemorrhage, invasive treatments such as laser photocoagulation or anti-VEGF injections are not indicated.
- Stability Over Time: Over a follow-up period exceeding one year, morphological features of both the retinoschisis and microvascular changes remained completely stable without intervention.
- Electronegative ERG is Not Exclusive to XLRS: An electronegative scotopic ERG waveform can occur in extensive SNIFR, reflecting extensive synaptic or post-photoreceptoral inner retinal disruption.
