Purpose: To investigate the effect of prophylactic subthreshold macular grid laser photocoagulation on drusen area, and to evaluate visual outcome and incidence of new CNV formation in patients with bilateral soft drusen maculopathy.Desigin: Non-randomized, non-masked clinical trial.Methods: Fourteen patients (28 eyes) with bilateral soft drusen maculopathy were enrolled in this prospective pilot study. In each patient, one eye was treated with 48 subthreshold (invisible end point) applications of KTP-laser (532nm) in a macular grid pattern and the fellow eye was observed.Soft drusen area and chorioretinal atrophy surface area were calculated at baseline and follow-up (3,6,12 months) and compared between two groups. BCVA was also compared in observation and laser- treated eyes.Main Outcome Measures: Reduction of drusen area, change in visual acuity, and rate of new choroidal neovascularization (CNV) formation.Results: At baseline, there was no significant difference in mean drusen surface area between two groups (P=0.90). Mean surface area of soft drusen in treated eyes was 6.54mm2 after one year and 7.56mm2 (P=0.50) in control eyes. There was a trend towards reduction of mean soft drusen area after one year from baseline in treated eyes.(6.54 versus 7.03mm2).In treated eyes, there was no statistically significant difference between mean BCVA at baseline (0.29 logMAR) and after 12 months (0.32 logMAR) (P=0.40).Conclusion: In our study, subthreshold KTP-laser (532nm) macular grid photocoagulation in bilateral soft drusen did not seem to reduce drusen surface area significantly and did not improve BCVA after one year. No exudative lesion developed in laser-treated eyes. A large, multicenter, prospective, randomized clinical trial with longer follow-up is needed to determine the efficacy of treatment in reducing soft drusen area and the rate of CNV formation.