Optical Coherence Tomography Angiography of Retinal Vein Occlusion.

Retinal vein occlusion is the second most common cause of retinal vascular disease after diabetic retinopathy and is a frequent cause of significant vision loss and associated morbidity. Currently, fluorescein angiography is the gold standard for imaging of the retinal and choroidal vasculature. However, this imaging modality is invasive, involving the use of an intravenous contrast agent that can cause systemic side effects and rarely, anaphylaxis. Optical coherence tomography angiography is a noninvasive, depth-resolved imaging modality that allows for the appreciation of spatial relationships of fundus vessels and enables detailed en face visualization of the superficial and deep retinal vasculature separately without the risk of adverse affects associated with the intravenous administration of fluorescein dye. When viewed alongside corresponding structural B-scans, optical coherence tomography angiography demonstrates almost all of the clinical and fluorescein angiographic findings that are characteristic of acute and chronic retinal vein occlusion, such as a decrease in capillary perfusion, macular edema, vascular dilation, foveal avascular zone enlargement, and venous-venous collateral formation.