Macular oedema secondary to retinal vein occlusion (RVO) can cause vision loss due to blockage of the central retinal vein (CRVO) or a branch retinal vein (BRVO). This systematic review assessed the efficacies of widely used treatments for macular oedema secondary to RVO and the feasibility of conducting indirect comparisons between these therapies.
A systematic review was undertaken in November 2010, including a literature search for trials in medical databases and relevant websites. Abstracts, conference presentations and unpublished studies were considered. Studies were data-extracted and quality assessed by two independent researchers. Outcome measures included the mean change in best corrected visual acuity (BCVA) from baseline in the study eye and/or number of patients gaining at least 10 letters from baseline to 6 months or the nearest equivalent time point.
Fourteen unique randomized controlled trials (RCTs) were identified. Ranibizumab 0.5 mg produced greater improvements in BCVA at 6 months than sham in BRVO (mean difference 11.0 letters, 95% confidence interval [CI] 7.83, 14.17) and CRVO (mean difference 14.10 letters, 95% CI 10.51, 17.69) in two double-blind sham-controlled RCTs. Pooled data from two double-blind, sham-controlled RCTs showed that improvements in BCVA were also significantly better for dexamethasone intravitreal (IVT) implant 0.7 mg compared with sham in patients with BRVO or CRVO (mean difference 2.5 letters, 95% CI 0.7, 4.3); the difference was significant for BRVO alone, but not CRVO alone. A significantly greater proportion of patients with BRVO gained ≥15 letters with laser therapy vs. no treatment at 36 months in a large prospective RCT (odds ratio 3.16, 95% CI 1.25, 8.00), whereas no difference was observed at 9 months in a smaller study. Three studies reported no benefit for laser therapy in CRVO. No indirect comparisons with ranibizumab were feasible due to differences in study design and baseline characteristics.
Data from RCTs for ranibizumab and dexamethasone IVT demonstrate that both new agents constitute significant improvements over the previously widely accepted standard of care (laser therapy) for the treatment of BRVO and CRVO. However, head-to-head studies are needed to assess the relative efficacies of licensed therapies for RVO.