Epidemiology, onset & clinical features


Degenerative retinoschisis affects about 5-7% of the adult population. Occurrence in up to 22% of individuals older than 40 years has been reported. Both genders are equally affected. No ethnical predisposition has been found.


Based on histopathological criteria, two forms of degenerative retinoschisis have been described:

    • typical (flat) retinoschisis characterized by: adhesion of cystic lesions as a result of degeneration of neuroretinal and glial supporting elements within areas of peripheral cystoid degeneration; deep separation of the retina into an inner and an outer layer; the inner layer contains the inner limiting membrane, retinal vessels, and inner plexiform layer, whereas the outer layer has portions of the outer plexiform, outer nuclear, and photoreceptor layers.

    • reticular (bullous) retinoschisis characterized by: an extremely thin inner wall consisting of inner limiting membrane, remnants of the nerve fiber layer, attenuated blood vessels, and complete loss of the supporting radial pillars.


Clinical features

The disease is asymptomatic in majority of cases. Advanced cases may present a large peripheral visual field defect corresponding to the area of retinoschisis. Unselected clinical series reveal a bilateral occurrence in approximately 80% of cases, with typically symmetrical presentation between the eyes. The schisis is most frequently located in the inferior temporal quadrant, has a discrete border and is immobile. There is no associated pigmentation of the retinal pigment epithelium or vitreous. Blood vessels on the inner retinal layer may be white and sheathed, and white ‘snowflakes' may be visible.

Single or multiple retinal holes (outer retinal holes being more common than inner retinal breaks) are rare and occur in less than 20% of cases, creating a risk for secondary retinal detachment. Retinal detachments associated with retinoschisis are two types: a localized, relatively stable and asymptomatic form usually presenting with outer retinal holes only; a rapidly progressive form presenting with retinal breaks in both layers. The asymptomatic form is much more frequent than the symptomatic one (ratio of about 180:1). Retinoschisis is responsible for less than 2.5% of all rhegmatogenous retinal detachments. Tractional retinal tears in retinoschisis are extremely rare.

The hallmark feature of the disease is foveal schisis (retinal splitting) though over time this may become less distinct. More than 50% of patients have some peripheral retinoschisis (mostly in the inferotemporal region) that can vary from shallow schisis to marked elevation in the inner leaflet over a large retinal area. Breaks occur within the inner layer varying from small holes to large tears. Vessels crossing between the walls of the schisis may be unsupported and at risk of hemorrhage. Additional peripheral changes may include pigmentation, which can resemble retinitis pigmentosa, sublinear retinal fibrosis, white retinal flecks and vascular attenuation or sheathing. Some patients present an inner retinal reflex resembling a tapetal reflex. XLRS may progress to retinal detachment in 5-22% of affected individuals, including infants with severe retinoschisis. Four to 40% of individuals with XLRS may develop vitreous hemorrhage.

Carrier females almost always have normal visual function and normal electroretinogram (ERG). Rarely, white flecks or areas of schisis in the peripheral retina can be present. So far, affected females have been reported only twice in the literature, one of these report describing females with XLRS from a highly consanguineous Columbian family.