Argon laser trabecular surgery as an alternative to carbonic anhydrase therapy.

Thirty-four eyes (25 patients) with diagnosed chronic open angle glaucoma on maximal medical therapy were studied to determine whether argon laser trabecular surgery was a desirable alternative to carbonic anhydrase therapy. Ninety-four per cent of patients responded favourably to argon laser trabecular surgery as an alternative to carbonic anhydrase therapy. The average pressure drop was 9.9 mm Hg. Interestingly, there was a mean drop of 4.2 mm Hg in the contralateral eye. There was minimal, if any, iris response although there was a small but probably not clinically significant decrease in corneal endothelial cell count. Blanching of the trabecular wall was used as the endpoint to help minimize post-laser pressure rise. Blacks and aphakic patients responded satisfactorily. Laser surgery is best reserved for those patients with a pretreatment intraocular pressure no higher than the 30 to 35 mm Hg level. Trabeculectomy, in spite of its known complications, offers a better prognosis in those cases where the pretreatment pressure exceeds the 30 to 35 mm Hg level.