Simulated treatment of recurrent choroidal neovascularization in primate retina: Comparative histopathologic findings

We simulated the treatment of recurrent choroidal neovascular membranes (CNVM) by applying two courses of laser treatment to monkey retinas. Argon green, argon blue-green, and krypton red lasers (KRLs) were used in juxtafoveal, papillomacular bundle, and nonmacular areas. The effects were examined clinically and histopathologically. Results of once-treated control eyes were consistent with those of previous studies. Repeat treatment, however, resulted in full-thickness retinal destruction or necrosis with all laser modalities and in all fundus locations. These results are consistent with the absorptive characteristics of xanthophyll and melanin and suggest only limited advantages to the KRL when treatment of recurrent CNVM is performed in a previously treated area of the fundus. However, treatment of recurrent CNVM is still probably most successful with a KRL, because recurrent CNVM is usually at a border of a photocoagulation scar, where the retina is still untreated, and because histologic studies have demonstrated inner retinal sparing with a KRL in juxtafoveal areas.