A case of undiagnosed X-linked retinoschisis presenting as unilateral macular demarcation line.

We intend to describe an uncommon presentation of X-linked juvenile retinoschisis (XLRS) in a 17-year-old boy showing a macular demarcation line in the right eye and an inferior peripheral bullous retinoschisis in both right and left eye, at his first ophthalmologic examination. The patient underwent a complete ophthalmologic examination including best-corrected visual acuity assessment, anterior segment and dilated fundus examination, ultra-wide-field retinography, spectral-domain optical coherence tomography, fundus autofluorescence, fluorescein angiography, electroretinography, visual field test, and genetic molecular testing. We report a rare case of genetically confirmed XLRS, presenting as a unilateral mildly-pigmented macular demarcation line (advanced sequel of unilateral spontaneous retinal reattachment of a previous retinal detachment or bullous retinoschisis) without foveoschisis in the fellow eye. XLRS is the most frequent cause of macular retinoschisis. The hallmark of XLRS is the evidence of a foveoschisis presenting with a characteristic spoke-wheel aspect in patients younger than 30 years of age. It is important to recognize uncommon presentations of XLRS so that the correct diagnosis is made, in order to provide the patients with appropriate genetic counseling and therapeutic care.