Photocoagulation of the fovea.

The visual outcome, histopathology, and electrodiagnostic tests of a man with a malignant melanoma of the choroid who received foveal argon laser photocoagulation prior to enucleatiion are described. The low intensity foveal burn destroyed only the outer retinal layers and spared the inner retina. Vision was reduced to 20/50 immediately, but recovered to 20/30 after one day. The visually-evoked-potential (VEP) was altered in both amplitude and waveform by the small foveal burn. A patient with solar retinopathy and permanent visual loss demonstrated only waveform changes on VEP testing. Monkeys with mild experimental foveal burns demonstrated outer layer retinal damage and waveform changes on VEP testing. The retinal energy density threshold for argon laser photocoagulation of the fovea is lower than 0.13 joules/mm.2.