Steroids and macular edema from retinal vein occlusion

The possibility of applying long-lasting steroids, such as triamcinolone and subsequently dexamethasone implant, directly in the eye, without the systemic side effects observed after their oral or intravenous administration, aroused great enthusiasm among ophthalmologists.

The SCORE study, a multicenter clinical trial, compared the efficacy and safety of 1-mg and 4-mg doses of preservative-free intravitreal triamcinolone with observation in central retinal vein occlusion (CRVO) participants with macular edema secondary to perfused CRVO. This study marked a turning point in the management of retinal vein occlusion (RVO), since it was the first report on an effective treatment of macular edema due to CRVO. But in branch retinal vein occlusion (BRVO), the SCORE study showed no difference in visual acuity for the standard care group compared with the triamcinolone groups; however, the rates of adverse events (particularly elevated intraocular pressure and cataract) were highest in the 4-mg group. The authors concluded that laser grid photocoagulation should remain the benchmark against which other treatments should be compared. The Geneva Study, a randomized, controlled, clinical trial, conducted to evaluate the safety and efficacy of an intravitreal implant that delivers sustained levels of dexamethasone (Ozurdex™), studied the largest group of RVO patients with macular edema (1267 patients), including 35% CRVO and 65% BRVO. The study demonstrated that this slow-release device could both reduce the risk of vision loss and improve the speed and incidence of visual improvement in eyes with macular edema secondary to CRVO and BRVO, with fewer side effects, such as elevation of intraocular pressure or cataract. Other ongoing studies evaluate the safety and efficacy of anti-vascular endothelial growth factor injection; preliminary results showed that these therapies are effective in decreasing macular edema and improving visual acuity, with fewer ocular adverse effects, but their duration of action seems limited.

These recent studies result in a great change in the management of macular edema from RVO. Unfortunately, long-term studies on safety and efficacy are not yet available, and further studies will have to show whether the short-term benefits are only transient or may finally lead to a long-lasting improvement in vision.