In a group of 121 eyes the author compared three methods of argon laser trabeculoplasty (ALT). Using the method of 360 degrees ALT 1.0 W 30 eyes were treated, using the method 180 degrees ALT 1.0 W 60 eyes and by the method of 180 degrees ALT 0.5 W 31 eyes. After a mean observation period of 11.5 +/- 3.6 months compensation was achieved in 81% and there were no significant differences between different methods. Improved efflux was most marked (by 100%) in method 180 degrees ALT 0.5 W where also the incidence of complications was significantly lower, as compared with the other two methods (P less than 0.01) and the postoperative course was practically without risk.