The outcome of low-frequency intravitreal bevacizumab therapy for macular edema in retinal vein occlusions

AIM: We aimed to evaluate the 1-year efficacy and safety of low-frequency intravitreal bevacizumab in the treatment of macular edema due to retinal vein occlusions (RVOs). METHODS: The study comprised an interventional prospective study of patients with macular edema due to central retinal vein occlusion (CRVO) or branch retinal vein occlusion, followed for 12 months. Treatment-naïve patients with reduced best-corrected visual acuity (BCVA) and central macular thickness (CMT) of at least 250 μm received intravitreal injection of bevacizumab. After 1 month, BCVA and optical coherence tomography (OCT) images of the macula were recorded. In patients with <30% improvement in BCVA and CMT, two more injections were applied at 1.5-month intervals. In all other patients, further injections were applied as needed. In cases with ischemic areas of retina, laser photocoagulation of the retina was performed. RESULTS: In total, 33 patients with CRVO and 55 with BRVO were treated. After 1 year, 65 eyes (73.86%) had clinically significant improvement of BCVA (>0.3 log of the minimum angle of resolution [logMAR] units) with average number of injections of 1.98. Improvement of mean BCVA in CRVO was significant (P=0.001) from baseline (1.2±0.95 logMAR units) to 1 year (0.75±0.6 logMAR units). Significant improvement of mean BCVA (P<0.001) was also found in BRVO, from 0.71±0.75 logMAR units at baseline to 0.28±0.5 logMAR units at 1 year. Baseline CMT was 852.21±298.20 μm for CRVO and 597.95±185.63 μm for BRVO. In both groups, there was significant decrease (P<0.001) in CMT after 1 year of treatment. Panretinal laser photocoagulation was done in 75.8% of all eyes with CRVO and sectoral photocoagulation in 49.1% of eyes with BRVO. CONCLUSION: In macular edema due to RVO, intravitreal bevacizumab provides improvement in visual acuity and reduction of macular edema in a high percentage of treated eyes after 1 year, even with low number of injections.