Purpose: The purpose of this study was to prospectively study the efficacy of grid laser combined with intravitreal bevacizumab or ranibizumab in eyes with macular edema due to branch retinal vein occlusion.
Patients and methods: Treatment-naïve eyes were enrolled to receive injections of ranibizumab or bevacizumab. During the first 6 months, patients were evaluated monthly and injected if the best-corrected visual acuity changed by five or more letters or fluid was noted on spectral domain optical coherence tomography (OCT); during the next 6 months, patients were evaluated bimonthly and injected only if the best-corrected visual acuity decreased by five or more letters with the associated fluid. Grid laser photocoagulation was performed if there was fluid on OCT and was repeated if patients were eligible after a minimum interval of 3 months.
Results: The mean numbers of ranibizumab and bevacizumab injections were, respectively, 3.2±1.5 and 3.0±1.4 in the first 6 months and 0.3±0.6 and 0.3±0.6 in the last 6 months. Moreover, 55/75 (73.33%) participants did not receive any injections in the last 6 months. The mean reductions in central retinal thickness at 12 months were 165.67 μm (P<0.001; 95% confidence interval -221.50 to -135.0) in the ranibizumab group and 184.78 μm (P<0.001; 95% confidence interval -246.49 to -140.0) in the bevacizumab group (P=0.079). More patients in the bevacizumab group compared to those in the ranibizumab group required rescue laser at 12 months (20 vs eleven; P=0.06).
Conclusion: Bimonthly evaluations after month 6 with very few pro re nata injections were effective in maintaining visual gains achieved during the first 6 months. Grid laser photocoagulation is effective in maintaining the vision even in the presence of fluid on OCT, although it's required more often in patients treated with bevacizumab.
Keywords: PRN dosing; grid laser; randomized clinical trial; visual acuity.