Effects of the Nd:YAG laser on the primate retina and choroid.

The effects of the neodymium:YAG laser in the thermal mode on the subhuman primate retina were studied with ophthalmoscopy, intravenous fluorescein angiography, light microscopy, transmission electron microscopy, and scanning electron microscopy using a plastic injection-corrosion technique. Representative samples were examined at 24 hours, 14 days, and 28 days after treatment. The burns appeared to predominantly affect the outer half of the retina and the inner half of the choroid, although with higher energy levels the inner retinal layers were occasionally involved. In most instances Bruch's membrane was disrupted. The injured choriocapillaris underwent a reparative process during a four-week period in which the discrete lesions observed at 24 hours had disappeared.