Central Retinal Vein Occlusion: Modifying Current Treatment Protocols

M Ashraf; AAR Souka; RP Singh

Disclosures

Eye. 2016;30(4):505-514. 

In This Article

Abstract and Introduction

Abstract

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.

Introduction

Central retinal vein occlusion (CRVO) is an acute retinal vascular condition that can severely affect visual acuity.[1] Previous studies estimated that ~2.5 million people worldwide are affected by CRVO and about 13.9 million people are affected by branch retinal vein occlusion (BRVO).[2] Visual loss after CRVO commonly occurs as a result of macular edema, macular ischemia, or in more advanced stages, vitreous hemorrhage, and neovascularization.[3]

CRVOs have been traditionally classified into ischemic and non-ischemic based on the degree of capillary non-perfusion on fluorescein angiography.[4] The most commonly used criteria for ischemic CRVO was determined by the CVOS study group, which defined ischemic CRVO as at least 10 disc areas of capillary non-perfusion.[5]

Differentiating both subtypes is important because it allows us to predict the natural history for these patients and how they will respond to therapy. The ischemic subtype of CRVO accounts for about 20% of cases and is associated with worse initial presenting visual acuity (VA) and poor visual prognosis even after edema resolution.[6] A cohort study showed that presenting VA in ischemic CRVO patients was (6/30) or better in only 1% of ischemic CRVO patients compared with 78% of non-ischemic patients.[6] Furthermore, final VA after resolution was better than 6/30 in only 12% of ischemic CRVO patients compared with 83% in non-ischemic patients. Stratifying patients early based on the perfusion state and the initial presenting visual acuity is useful in predicting outcomes.[6,7]

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