Histopathology of neodymium: YAG laser iridectomy in humans

Fifteen peripheral iridectomy specimens were obtained, with informed consent, from patients with primary narrow angle glaucoma, after previous neodymium:YAG (Nd:YAG) laser iridectomy. The iridectomies were performed three hours to ten weeks after laser application. Iridectomy specimens were examined by scanning and/or transmission electron microscopy. Early effects of the Nd:YAG laser on the iris were mild hemorrhage and fibrinous aggregates. There were no inflammatory cell infiltrates. At later time intervals (up to 2 months post-laser treatment) the holes showed irregular thickness of iris pigment epithelium at the margins, and tissue atrophy limited to the immediate margins of the hole. Elsewhere the iris was structurally intact. The diameter of the holes varied from 60 to 500 microns. The larger holes corresponded to cases that had received more application shots.