In this prospective, randomised trial, 19 patients (mean age 72.2 +/- 6.6 years) with soft drusen maculopathy and good visual acuity (0.93 +/- 0.1) were treated with argon green laser photocoagulation. Fundus colour photography and fluorescein angiography were performed at study entry and after 3, 6 and 12 months. Nineteen patients (mean age 68.5 +/- 6.2 years) with visual acuity 0.95 +/- 0.1 and similar fundus changes served as a control group. The area occupied by drusen within a circular zone was calculated in the fundus colour photographs (radius 2500 microns) and in the angiograms (radius 1250 microns). Mean drusen area of the treatment group did not differ from that of the control group at study entry (p > 0.5-0.7). In the treatment group, mean drusen area had decreased significantly from 7.87% to 2.93% (p = 0.00013) and from 19.22% to 7.15% (p < 0.0001) at 12 months respectively in the colour photographs and in the angiograms. Visual acuity and colour contrast sensitivity did not change. No complications were seen in the treated group. In the control group, mean drusen area increased from 8.33% to 10.69% and from 17.41% to 22.05%, respectively. These differences did not reach statistical significance. When comparing the 12-month change in drusen area in the two groups, significant differences were found both in fundus colour photographs and angiograms (p < 0.001). In the control group, mean visual acuity decreased to 0.89 +/- 0.1 (p = 0.008) and mean colour contrast threshold for the tritan axis increased significantly (p = 0.044), indicating impairments of retinal function. Three patients in the control group advanced to an exudative stage of the disease.