Efficacy of conbercept after switching from bevacizumab/ranibizumab in eyes of macular edema secondary to central retinal vein occlusion

AIM: To explore the efficacy of conbercept after switching from bevacizumab/ranibizumab in eyes of central retinal vein occlusion (CRVO) through optical coherence tomography angiography (OCTA). METHODS: Patients with prior treatment of a minimum of three consecutive intravitreal injections of either bevacizumab or ranibizumab, followed by injection of conbercept, were recruited. The minimal follow-up period after switching was 12mo. Central retinal thickness (CRT), best-corrected visual acuity (BCVA), the interval of injections was reviewed. Perfusion density (PD) and vascular length density (VLD) of superficial and deep capillary plexus were acquired from OCTA images before and after switching. RESULTS: Twenty-four eyes were included. CRT significantly decreased from 460.71 +/- 153.23 mu m (before switching) to 283.92 +/- 38.27 mu m at the end of follow-up (P<0.001). However, BCVA gained to some extent (from 0.98 +/- 0.33 to 0.76 +/- 0.42 logMAR) but the difference was not significant (P=0.070). After switching to conbercept the injection interval extended from 5.2 +/- 2.3wk to 8.3 +/- 3.9wk (P=0.012). At the end of follow-up, PD of deep retinal layer decreased significantly compared with before switching (from 34.62%+/- 5.27% to 33.26%+/- 5.82%, P=0.016), similar result was found in VLD of deep retinal layer but not in PD or VLD in superficial layer. CONCLUSION: In cases of refractory macular edema secondary to CRVO, switching to conbercept improves macular thickness and extends interval of injection. Retinal microvasculature cannot improve with treatment of conbercept.