Do any factors predict a favourable response to laser trabeculoplasty?

One hundred and thirty-three eyes with raised intraocular pressure treated by argon laser trabeculoplasty were studied to determine the factors predicting a fall in pressure with treatment. The two main predictive factors were: (i) initial pressure--a higher initial pressure was associated with a greater fall in pressure (p less than 0.001); and (ii) diagnosis (type of glaucoma)--pseudoexfoliative glaucoma (PXFG) and chronic open-angle glaucoma (COAG) had the greatest fall (p less than 0.05). Aphakic glaucoma was associated with the worst results. Of the other factors studied, only the degree of pigmentation of the angle was a significant predictor: the greatest fall in pressure occurred in eyes with moderately pigmented angles (p = 0.05). Complications of treatment were pigment scatter in the angle with depigmentation (41% of eyes), peripheral anterior synechiae (7.5%), immediate postoperative rise in pressure of 10 mmHg or more (7%), moderately severe iritis (3%) and hyphaema (2%). Medication was able to be ceased in only five patients after laser trabeculoplasty; even if a small fall in pressure is achieved, a large fall to the bottom of the normal range is unlikely.