Retinal vascular changes associated with transpupillary thermotherapy for choroidal melanomas

Purpose: To define retinal vascular changes after transpupillary thermotherapy (TTT) for choroidal melanomas and assess their clinical impact. Methods: Stereoscopic fluorescein angiogram pairs of 29 patients pre- and post-treatment with TTT were examined for patterns of vascular damage, and the patients were studied for ensuing complications. Results: Widespread retinal capillary loss was confined within the treatment margins except in cases of coexisting large retinal artery or vein occlusions. Artery occlusions occurred in 83%, involving a large artery in 23%. Venous occlusions occurred in 69%, involving large veins in 10%. Subretinal choroidal neovascularization occurred in four cases, in one causing hemorrhage that broke through into the vitreous. No retinal neovascularization occurred. Choroidal vasculature was relatively preserved at the periphery of the treated area. Foveal vascular damage caused visual loss in six cases. Vascular changes beyond the treatment margins did not affect the fovea in any case. Retinal fibrosis affected two cases. Diabetic patients fared no worse than healthy counterparts. Conclusions: Transpupillary thermotherapy produces characteristic retinal vascular changes that may reduce vision when affecting the fovea. Vascular changes are confined within the treatment margins except in cases of associated large vessel occlusion. There is a small risk of neovascularization, both retinal and choroidal.