Long-term reduction of intraocular pressure after repeat argon laser trabeculoplasty.

Thirty-eight eyes (in 31 patients with glaucoma) that had shown a favorable response to an initial argon laser trabeculoplasty had a repeat laser trabeculoplasty four to 81 months (mean +/- S.E.M., 23 +/- 3 months) later because of inadequately controlled intraocular pressures. A mean (+/- S.E.M.) of 65 +/- 3 burns (range, 50 to 115) were given during the initial laser trabeculoplasty, and 58 +/- 2 burns (range, 36 to 100) were given during the first repeat treatment. Three months after the first repeat laser trabeculoplasty, one eye (3%) had undergone filtering surgery and 30 eyes (78%) were considered successes. Of the 30 eyes that were followed up for 12 months after the first repeat laser trabeculoplasty, two (7%) had undergone filtering surgery, three (10%) had received a second repeat laser trabeculoplasty, and 22 (73%) were successes. Fifteen eyes underwent a second repeat laser trabeculoplasty at six to 47 months (mean +/- S.E.M., 21 +/- 3 months) after the first repeat laser trabeculoplasty. Seven (47%) of these eyes required filtering surgery within three to 12 months after the second repeat laser trabeculoplasty. Four of 38 (11%) of the initial, two of 38 (5%) of the first repeat, and zero of 15 of the second repeat laser trabeculoplasty treatments resulted in a one- to two-hour rise in intraocular pressure of at least 10 mm Hg.