ARGON GREEN VS KRYPTON RED LASER PHOTOCOAGULATION FOR EXTRAFOVEAL CHOROIDAL NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION - 3-YEAR RESULTS OF A MULTICENTER RANDOMIZED TRIAL

Objective: To determine whether argon green laser (AGL) or krypton red laser (KRL) is superior for the treatment of well-defined extrafoveal choroidal neovascularization (CNV) in patients with age-related macul ar degeneration (AMD) after 3 years of follow-up. Design: Multicentre randomized clinical trial. Setting: University-based referral practice s in Canada. Participants: Among 210 patients selected by ophthalmolog ists at 13 participating centres there were 191 eligible patients aged 50 years or more with angiographically proven CNV whose posterior edg e was 200 to 2500 mu m from the foveal avascular zone. Other inclusion criteria included the presence of drusen in either eye, a best correc ted visual acuity in the study eye of at least 35 letters on the Early Treatment Diabetic Retinopathy Study chart (equivalent of 20/200 or b etter on the Snellen chart) and no prior photocoagulation in the study eye. The patients were randomly assigned to receive either AGL (96 pa tients) or KRL (95 patients) treatment. Interventions: Treatment with 200-mu m spots of 0.2 to 0.5 seconds' exposure to produce a homogeneou s grey white lesion that completely covered the CNV. Outcome measures: Change from baseline in visual acuity at 1, 2 and 3 years (primary me asure), development of persistent or recurrent CNV (secondary measure) . Results: There were no significant differences between the treatment groups in drop-out rates, No significant differences were found betwe en the two groups in loss of visual acuity or angiographic evidence of persistent or recurrent CNV. Conclusion: KRL is no better than AGL in preserving vision and preventing loss of visual acuity in patients wi th AMD with well-defined extrafoveal CNV followed for 3 years.