Effects of argon (green) laser treatment of soft drusen in early age-related maculopathy: a 6 month prospective study.

Abstract

To evaluate whether perifoveal laser photocoagulation of soft drusen reduces the total area occupied by drusen. In a prospective, randomised study, 20 patients (mean age 71.3 (SD 7.7) years) with early age-related maculopathy (ARM) in the form of soft drusen and pigmentary changes and with good visual acuity (0.94 (0.09)) were treated with argon green laser photocoagulation. Mild laser burns (200 microns) were placed within a temporal horseshoe-shaped area, extending from a distance of no less than 500 microns from the centre of the fovea to the vascular arcades. They were placed on the drusen and scattered over areas where no drusen were present. Fundus colour photography and fluorescein angiography were performed at study entry as well as after 3 and 6 months. Nineteen age-matched patients (68.5 (6.2) years) with soft drusen maculopathy (visual acuity 0.95 (0.10)) were followed as a control group. Using a computer system, the area occupied by drusen was determined as a portion of the total area of a circle with a radius corresponding to 1250 microns in the fundus for the angiograms and 2500 microns for the colour photographs, respectively. At study entry, the mean area occupied by drusen in the treatment group was not significantly (p > 0.5-0.7) different from that of the control group. The mean drusen area of the angiograms and fundus colour photographs in the treated group decreased significantly from 19.3% to 13.8% (p = 0.002) and from 7.84% to 5.02% (p = 0.005), respectively. In the untreated group, the mean area occupied by drusen increased significantly from 17.4% to 20.4% (p = 0.030) and from 8.33% to 9.23% (p = 0.002), respectively. No significant changes in visual acuity (p > 0.05-0.5) or in visual fields (p > 0.05-0.3) occurred in either of the two groups during 6 months. The study suggests that the area occupied by soft drusen in patients with early ARM decreases after perifoveal laser photocoagulation but increases in an untreated control group.