Description and pathogenesis of late stages of retinopathy of prematurity.

The retinal and vitreous changes seen in retinopathy of prematurity (ROP) can be explained by proliferation and contraction of tissue originating in the shunt area. Avascular retina is stretchable, and therefore much of it stays attached, while vascular retina is nonstretchable and detaches. When the shunt area forms a circular ring, one of three distinct patterns of retinal detachment develops, according to whether the shunt area is anterior, equatorial, or posterior in location. The detachments of ROP are, typically, traction detachments.