Photocoagulation for retinal vein occlusion.

The role of photocoagulation in retinal vein occlusion (RVO) has been studied since 1974. The most serious complications of central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO) are: (i) visual deterioration, most commonly due to macular edema, and (ii) the development of ocular neovascularization (NV), particularly neovascular glaucoma (NVG), with hazardous consequences for vision and even the eye itself. Before discussing the role of photocoagulation in the management of NV and macular edema in RVO, it is crucial to gain a basic scientific understanding of the following relevant issues: classification of RVO, ocular NV in RVO, and the natural history of macular edema and visual outcome of RVO. These topics are discussed. In CRVO, ocular NV is a complication of ischemic CRVO but not of nonischemic CRVO. Photocoagulation has been advocated to prevent and/or treat the development of ocular NV and NVG. Since NVG is the most dreaded, intractable and blinding complication of ischemic CRVO, the role of photocoagulation and its management are discussed. Findings of three randomized, prospective clinical trials dealing with photocoagulation in ischemic CRVO are discussed. The role of photocoagulation in the management of ocular NV and macular edema in BRVO, and three randomized, prospective clinical trials dealing with those are discussed. Recent advent of intravitreal anti-VEGF and corticosteroid therapies has drastically changed the role of photocoagulation in the management of macular edema and NV in CRVO and BRVO. This is discussed in detail.