Splitting occurs in outer plexiform or inner nuclear layer. Splitting occurs in nerve fiber layer. Most congenital cases X-linked.
Holes can become quite large and flimsy retinal vessels bridge holes.
Eventually, no outer layer, only pigment clumps. Frequently affects the macula. In one study of 56 males from 16 families, macular abnormalities seen in all eyes. FA shows no dye leakage into these cystoid spaces, distinctly different from microcystoid macular edema. Macular finding may be only fundus finding in congenital retinoschisis.