Intravitreal Ranibizumab for Diabetic Macular Edema with Prompt versus Deferred Laser Treatment

Abstract

Objective: To report 3-year follow-up within a previously reported randomized trial evaluating prompt versus deferred (for ≥24 weeks) focal/grid laser treatment in eyes treated with intravitreal 0.5-mg ranibizumab for diabetic macular edema (DME). Design: Multicenter randomized clinical trial. Participants: Three hundred and sixty one participants with visual acuity of 20/32 to 20/320 (approximate Snellen equivalent) and DME involving the fovea. Methods: Ranibizumab every four weeks until no longer improving (with resumption if worsening) and random assignment to focal/grid laser treatment promptly or deferred (≥24 weeks). Main Outcome Measures: Best-corrected visual acuity and safety at the 156-week (“3-year”) visit. Results: The estimated mean change in visual acuity letter score from baseline through the 3-year visit was 2.9 letters greater (9.7 versus 6.8, mean difference = 2.9, 95% confidence interval 0.4 to 5.4, P = 0.02) in the deferral group compared with the prompt laser treatment group. In the prompt laser treatment group and deferral group, respectively, the percentage of eyes with a ≥10 letter gain was 42% and 56% (P = 0.02), while the percentage of eyes with a ≥10 letter loss was 10% and 5% (P = 0.12). Up to the 3-year visit, the median numbers of injections were 12 and 15 in the prompt and deferral groups, respectively (P = 0.007), including 1 and 2, respectively, from the 2- up to the 3-year visit. At the 3-year visit, the percentages of eyes with central subfield thickness ≥250 μm on time domain optical coherence tomography were 36% in both groups (P = 0.90). In the deferral group, 54% did not receive laser treatment during the trial. Systemic adverse events appeared similar in the two groups. Conclusions: These 3-year results suggest that focal/grid laser treatment at the initiation of intravitreal ranibizumab is no better, and possibly worse for vision outcomes, than deferring laser treatment for ≥ 24 weeks in eyes with DME involving the fovea and with vision impairment. Some of the observed difference in visual acuity at three years may be related to fewer cumulative ranibizumab injections during follow-up in the prompt laser treatment group. Follow-up through five years continues.