Forty-five phakic eyes with open-angle glaucoma and uncontrolled intraocular pressure underwent laser trabeculoplasty. Each eye was assigned randomly to one of three treatment groups: group 1, 100 spots over 360 degrees; group 2, 50 spots over 180 degrees; or group 3, 50 spots over 360 degrees. A 50-micron spot was aimed at the anterior meshwork; power and time were varied to achieve a blanch. Forty-four eyes were followed up for at least four weeks without further intervention. The mean IOP before therapy and the initial IOP elevation were similar in all groups. After four weeks, the mean IOP reductions in 15 eyes in group 1, 15 eyes in group 2, and 14 eyes in group 3 were not significantly different. However, significantly more eyes in group 1 demonstrated a greater than 12 mm Hg reduction in IOP than eyes in the other groups. Group 2 tended to have the fewest eyes with reduced medications.