Central retinal vein occlusion: modifying current treatment protocols

Central retinal vein occlusion (CRVO) is a common retinal vascular disorder that can result in severe visual acuity loss. The randomized control study, CRUISE, helped establish anti-VEGFs as the standard of care in cases with CRVO. The extension studies for CRUISE; HORIZON and RETAIN showed that not all visual gains are maintained beyond the first year. In addition, patients showed different behavior patterns; with some patients showing complete response with few recurrences, whereas others showed partial or even no response with multiple recurrences. Long-term follow-up demonstrated that patients responding poorly to anti-VEGFs tended to do so early in the course of treatment. It also demonstrated the effectiveness of a pro re nata (PRN) protocol for improving vision and maintaining these gains over long-term follow-ups. The SHORE study further illustrated this point by demonstrating that there were minimal differences in visual outcomes between patients receiving monthly injections and patients being treated PRN. In this review we analyzed the data from the major randomized clinical trials (RCT) that looked at anti-VEGFs as the primary treatment modality in patients with CRVO (CRUISE and the extension studies HORIZON and RETAIN for ranibizumab as well as GALILEO and COPERNICUS for aflibercept). In addition, we looked at SCORE and GENEVA to help determine whether there is a place for steroids as a first line therapy in current treatment practice. We then explored alternative treatment regimens such as laser therapy and switching between anti-VEGF agents and/or steroids for non or partially responding patients. Finally, we propose a simplified modified treatment algorithm for patients with CRVO for better long-term outcomes in all types of responders.