Long-term follow-up of argon laser trabeculoplasty in uncontrolled primary open-angle glaucoma. A study with standardized extensive preoperative treatment.

The long-term results of 180 degrees argon laser trabeculoplasty (ALT) were studied in 61 eyes of 43 patients with uncontrolled primary open-angle glaucoma [intraocular pressure (IOP) less than 22 mm Hg]. In order to enhance the relevance of this prospective study, only eyes that had not responded to medication despite standardized extensive therapy were followed up over an average period of 4.4 years [52.8 +/- 7.3 (mean +/- SD) months]. The success rate of treatment (decrease in IOP less than 5 mm Hg, IOP below 20 mm Hg, stable visual field, stable optic nerve head and no further laser or surgical intervention) after 4.4 years was 73.7%. The mean decrease in IOP was 8.5 +/- 2.9 mm Hg (mean +/- SD). Eyes receiving ALT before cataract surgery retained control of IOP after surgery. A comparable pressure control was also attained with those eyes that had undergone previous trabeculectomy. Failures (26.3%) all occurred in the 1st year after treatment. The results and conclusions from our study are compared with those reported in the literature. The different theories regarding the mechanisms of action of ALT are discussed.