Peripheral neovascularization complicating rhegmatogenous retinal detachments of long duration. Nine eyes in nine patients with rhegmatogenous retinal detachments of 1-18 years, duration showed clinical evidence of significant retinal neovascularization in the equatorial region. The retinal new vessels showed a sea-fan configuration. Their extent in the periphery of the fundus ranged from 10 degrees to 180 degrees. All retinal detachments were associated with round atrophic retinal holes in the equatorial region. Retinal reattachment was achieved in all eyes with scleral buckling. The retinal new vessels totally regressed within 15 days to 3 months after retinal reattachment. It is believed that the peripheral retinal new vessels were secondary to retinal hypoxia resulting from decreased retinal blood flow in the detached retina.