Retinal vein occlusions. 26/03/2013
Retinal vein occlusions (RVOs) have been defined as retinal vascular disorders characterized by dilatation of the retinal veins with retinal and subretinal hemorrhages and macular edema, and/or retinal ischemia. Fluorescein angiography (FA) remains essential for the diagnosis and prognosis of RVO, allowing recognition of the diverse types of RVO, such as perfused or nonperfused, as well as detection of the different modalities in natural history. F A is the most effective method to determine the presence (or absence) of macular cystoid edema, its extension, persistence, regression, or the degree of ischemia. Spectral domain optical coherence tomography (SD-OCT) helps to quantify the changes in retinal thickness, the amount of cystoid macular edema, and supplies additional information, such as whether the accumulated fluid is located mostly within the retinal layers or additionally in the sub retinal space. SD-OCT can display the presence and integrity of the outer limiting membrane and of the inner and outer segments of the photoreceptors, useful information for prognosis and a guide for treatment in the management of RVO. Laser photocoagulation in a 'grid' pattern over the area, demonstrated as leaking by FA, remains the 'reference treatment for macular edema due to branch retinal vein occlusion', according to the recent results of the SCORE Trial. Recent case series studies and prospective randomized trials strongly suggest an antiedematous effect of intravitreal steroids and an associated improvement in vision. These studies have suggested that intravitreal steroids (triamcinolone, fluocinolone, dexamethasone in a slow-release device) and intravitreal anti-VEGF drugs (bevacizumab, ranibizumab, pegabtanib) may at least temporarily reduce foveal edema and correspondingly improve visual function. Surgical treatment modalities have been reported for RVOs. The positive action of vitrectomy seems durable; the combination of surgery and intravitreal injection of steroids and/or an injection of tissue plasminogen activator could permit a more rapid and lasting action. However, strong data from randomized trials are warranted.