Argon laser trabeculoplasty in pigmentary dispersion syndrome with glaucoma.

Thirteen eyes in ten patients with pigmentary dispersion syndrome and glaucoma underwent argon laser trabeculoplasty. All eyes responded well initially with an average decrease in intraocular pressure of 10.6 mm Hg. The intraocular pressure in five of these eyes increased to levels higher than those before treatment after an average of nine months. This loss of control occurred in patients who were older (average age, 59 years vs 31 years) and who had had glaucoma for a longer period (10.2 years vs 2.5 years). There was no evidence of further pigment dispersion to explain failure. Trabecular sclerosis may have prevented the maintenance of an adequate trabecular "tightening effect" of argon laser trabeculoplasty. Because of its greater absorption in the deeply pigmented trabecular meshwork, the laser may actually cause further trabecular damage.