Optic nerve damage following argon laser photocoagulation in a human eye.

Argon laser photocoagulation of diabetic neovascular formations overlying the optic disc risks injury to the nerve fibers. Isolated reports of postoperative field defects have appeared but extensive pathologic studies of the effects on nerve fibers are lacking. In an eye with a malignant melanoma nasally, laser photocoagulation was directed at the superior temporal artery on the disc. Applications were made repeatedly until spasm was produced at two sites. The following day, the eye was enucleated. Histopathologic examination revealed loss of endothelial cells and absence of nuclei in the media of the treated artery, and coagulative necrosis of nerve fibers around the vessel. Extensive damage to the peripapillary outer segments and retinal pigment epithelium also was demonstrated.