PRESENTING AUTHOR

To investigate the microanatomical changes in the outer nuclear layer (ONL) following schisis resolution in two siblings harboring identical pathogenic variant in RS1 associated with X-Linked Retinoschisis (XLRS).

Sibling 1: 13-year-old male referred at age 7 with XLRS complicated by vitreous hemorrhage. Initial best-corrected visual acuity (BCVA) was 20/200 OD, 20/100 OS. Retinal examination revealed vitreous hemorrhage OD, foveal and peripheral schisis OU. Spectral-domain optical coherence tomography (SD-OCT) revealed central foveal thickness (CFT) of 778 μm OD, 589 μm OS. By age 12, had three episodes of vitreous hemorrhage OD (BCVA HM to 20/300 OD, 20/60 OS). At age 13, retinoschisis resolved (CFT 143/168 μm OD/OS), ONL thickness (33/35 μm OD/OS) and BCVA of 20/50 OD and 20/40 OS.

Sibling 2: 11-year-old male referred as a 5-year-old with XLRS and no visual complains (BCVA 20/50 OD, 20/40 OS). Fundus examinations since baseline appeared normal except for a blunted foveal reflex and discrete vitreous debris (no changes observed in 6 years of follow-up). CFT remained stable with discrete macular intraretinal cysts (228 μm OD, 221 μm OS). ONL thickness (72 μm OD, 70 μm OS). Final BCVA was 20/30 OU.

Previous studies reported CFT thinning in older XLRS patients. This study highlights, how persistent schisis led to reduced CFT and ONL thickness in one sibling, while the other, with discrete intraretinal cysts, maintained normal retinal thickness over 6 years.

Prolonged schisis may contribute to photoreceptor degeneration, resulting in a reduction in the ONL thickness and inducing microanatomical changes detectable on OCT.