Retinoschisis is defined as a splitting of the sensory retina into two layers, which most often results In an elevated lesion that resembles an intra-retinal blister. It is typically an acquired disorder that is nearly always found in the peripheral temporal fundus, either superior or inferior. The split is usually at the outer plexiform and inner nuclear layers. The typical lesion is dome shaped with the convex border pointing towards the posterior pole.

Retinoschisis must be differentiated from other membranous lesions such as retinal detachment and choroidal detachment. With B-Scan, a retinoschisis Is only about half as thick as a retinal detachment and both are much thinner than a choroidal detachment.