[Inhibitory effect of prior panretinal photocoagulation on experimental iris neovascularization]

We could produce iris neovascularization experimentally in rhesus monkey eyes, by occlusion of the major retinal vessels of the retina and persistent ocular hypotony. We confirmed that panretinal photocoagulation inhibits development of iris neovascularization. We evaluated the effect of panretinal photocoagulation one month before occlusion of major retinal vessels with secondary iris neovascularization in 3 monkey eyes. Rubeosis iridis appeared on day 5 and disappeared on day 14 after retinal vessel occlusion. Histologically, the newly formed vessels near the iris surface showed fenestrations and protruded into the anterior chamber. The endothelial cells were flat and similar to matured vessels. These findings were in sharp contrast to our previous experiments with panretinal photocoagulation after rubeosis iridis became manifest. The findings also showed that retinal scarring by preceding panretinal photocoagulation did not completely inhibit the iris neovascularization.