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.