Purpose: To detail the clinical, multimodal imaging and genetic findings of a patient with bilateral foveoschisis caused by the in-frame c.498_506del (p.Ile167_Gly169del) variant in CRB1, emphasizing distinctions from other hereditary cystic maculopathies. 

Case Description: A 19-year-old man presented with blurred vision (BCVA 20/40 OD, 20/50 OS). Anterior segment and peripheral retina were unremarkable. High-resolution macular OCT disclosed multilamellar intraretinal cavities and hyper-reflective "pillar" columns centred on the fovea; fundus autofluorescence showed a faint parafoveal hyper autofluorescent halo without vitelliform or fleck deposits. Full-field ERG was normal (b/a ≈ 1.6); Goldmann perimetry and color vision were intact. A 330-gene retinal dystrophy panel identified the heterozygous in-frame deletion c.498_506del in CRB1 and excluded variants in RS1, BEST1 and ABCA4. A localized CRB1-associated cystic maculopathy was diagnosed; semi-annual monitoring and genetic counseling were instituted. 

Conclusions: Hypomorphic CRB1 variants can produce isolated foveoschisis with preserved peripheral function and a normal ERG, clinically mimicking X-linked juvenile retinoschisis. High-resolution OCT combined with molecular confirmation is essential for accurate differential diagnosis, prognostication and potential enrolment in future CRB1 gene-based therapies.