X-linked juvenile retinoschisis is a form of vitreoretinal dystrophy that is characterized by foveal and peripheral splitting of the retinal nerve fiber layer. Pathognomonic of this disorder is a microcystic radiate appearance in the fovea. We encountered a 10 year-old, mildly retarded, Japanese boy, who exhibited a widely extended macular retinoschisis bilaterally. A break in the inner layer of the left eye mimicked a lamellar macular hole, which is a rare manifestation of the disease. Peripheral retinoschisis was absent. Only a few reports have described marked bilateral macular retinoschisis that involved entire posterior pole, while various other macular findings have been reported. This patient with a severe form of retinoschisis was found to harbor the deletion of 33 base pairs, including the boundary region of exon 3 and intron 3 in the XLRS1 gene.