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

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

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.

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.

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.

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