An argon laser iridotomy was performed on 53 eyes of 34 patients with closed-angle glaucoma. Technically, all of the iridotomies were successful. Blue irides were more resistant to treatment than brown irides. The iridotomies were performed with high energy of 2 W and a very short exposure time of 0.01 to 0.04 s, thus minimizing thermal damage to adjacent tissues. Patients with narrow angles who underwent preventive laser irodotomy benefited most from the procedure, and all the eyes of this group maintained a normal intraocular pressure (IOP) after the iridotomy. Of the 20 eyes with acute angle-closure glaucoma, 17 maintained a normal IOP after iridotomy, and only three were resistant to this treatment, calling for filtering operations later. The IOP of eyes with chronic closed-angle glaucoma did not change after the procedure, and the iridocorneal angles remained practically the same. Argon laser iridotomy by this technique is highly recommended as the procedure of choice for eyes with acute angle-closure glaucoma and for preventive iridotomy in the fellow eye. The procedure is simple, is performed in the outpatient clinic, and engenders no major complications.