Seventy-eight patients (109 eyes) with progressive glaucoma had argon laser trabeculoplasty as a substitute for filtration surgery and were then followed up for a minimum of 5 years. One hundred spots were placed at the anterior margin of the posterior trabecular meshwork over 360 degrees. Consecutive cases between 1980 and 1985 were reviewed, 95% of treated cases being included in the final analysis. Eighty-two eyes had primary open angle glaucoma. If only the group with primary open angle glaucoma is considered, the failure rate the first year was 19%. After that, the failure rate was approximately eight per year. At the end of 5 years, 65% of all eyes had failed. At the end of 10 years, data were available on 84 of the original 109 treated eyes; in 80 treatment had failed, and four were still receiving medical therapy.