Retinoschisis is an eye disease characterized by the abnormal splitting of the retinas neurosensory layers, usually in the outer plexiform layer. Retinoschisis can be divided into degenerative forms which are very common and almost exclusively involve the peripheral retina and hereditary forms which are rare and involve the central retina and sometimes the peripheral retina. The degenerative forms are asymptomatic  and involve the peripheral retina only and do not affect the visual acuity. Some rarer forms result in a loss of vision in the corresponding visual field.Almost all cases are X-linked recessive and caused by a mutation in the retinoschisin gene (RS1). Classification
Hereditary
X linked juvenile retinoschisis
Familial foveal retinoschisis
Tractional
Exudative
Secondary to Optic disc pit
Degenerative
Typical
Reticular

Degenerative retinoschisis
This type of retinoschisis is very common with a prevalence of up to 7 percent in normal persons. Its cause is unknown. It can easily be confused with retinal detachment by the non-expert observer and in difficult cases even the expert may have difficulty differentiating the two. Such differentiation is important since retinal detachment almost always requires treatment while retinoschisis never itself requires treatment and leads to retinal detachment (and hence to visual loss) only occasionally. Unfortunately one still sees cases of uncomplicated retinoschisis treated by laser retinopexy or cryopexy in an attempt to stop its progression towards the macula. Such treatments are not only ineffective but unnecessarily risk complications.
This may occur in:
a) The vitreomacular traction syndrome; b) Proliferative diabetic retinopathy with vitreoretinal traction; c) Atypical cases of impending macular hole. Exudative retinoschisis
Retinoschisis involving the central part of the retina secondary to an optic disc pit was erroneously considered to be a serous retinal detachment until correctly described by Lincoff as retinoschisis. Significant visual loss may occur and following a period of observation for spontaneous resolution, treatment with temporal peripapillary laser photocoagulation followed by vitrectomy and gas injection followed by face-down positioning is very effective in treating this condition. Diagnosis
The diagnosis of the disease is usually made during an examination of the back of the eye (fundus) where any splits, tears or rips may be seen. One diagnostic tool is optical coherence tomography (OCT), which that uses light waves to create images of the retina and based on ophthalmoscopy with scleral depression and contact lens examination. The fellow eye should also be examined. Treatment
Retinoschisis usually doesn’t require treatment aside from glasses to improve vision. However, some children with X-linked retinoschisis may have bleeding in their eye. This can be treated with either laser therapy or cryosurgery. In rare cases, children may need surgery to stop the bleeding. As of 2022, a clinical trial of gene therapy to treat XLRS was ongoing. After 1 year, the paper concluded that the therapy "was generally safe and well tolerated but failed to demonstrate a measurable treatment effect". References
External links

GeneReview/NCBI/NIH/UW entry on X-Linked Juvenile Retinoschisis
X-linked juvenile retinoschisis on Genetics Home Reference
NCBI Genetic Testing Registry