Natural history of central retinal vein occlusion: an evidence-based systematic review.

Objective: To describe the natural history of central retinal vein occlusion (CRVO) based on the best available evidence from the literature.

Clinical Relevance: Central retinal vein occlusion is a common sight-threatening retinal vascular disease. Despite the introduction of new interventions, the natural history of CRVO is unclear.

Methods: Systemic review of all English language articles retrieved using a keyword search of MEDLINE, EMBASE, Current Contents, and the Cochrane Library to November 13, 2008. This was supplemented by hand-searching references of review articles published within the last 5 years. Two investigators independently identified all relevant observational studies evaluating the natural history of RVO and all clinical trials evaluating interventions for CRVO; an untreated control arm was included.

Results: Of 5966 citations retrieved, 53 studies were reviewed, providing 3271 eyes with CRVO for analysis of its natural history. Visual acuity (VA) was generally poor at baseline (<20/40) and decreased further over time. Although 6 studies reported an improvement in VA, none of these improvements resulted in VA better than 20/40. Up to 34% of eyes with nonischemic CRVO converted to ischemic CRVO over a 3-year period. In ischemic CRVO cases, neovascular glaucoma developed in at least 23% of eyes within 15 months. In nonischemic CRVO cases, macular edema resolved in approximately 30% of eyes over time, and subsequent neovascular glaucoma was rare.

Conclusions: Untreated eyes with CRVO generally had poor VA, which declined further over time. One quarter of eyes with nonischemic CRVO converted to ischemic CRVO.