Branch and Central Retina Artery Occlusion and its treatment according to OCT-A Findings

The retina requires a large blood supply to cope with the metabolic demands of the tissue, so it is vulnerable to hypoxia when the arterial blood flow is obstructed. Retinal artery occlusions are not common, but they can cause severe vision loss and may be indicative of cardiovascular disorders, such as cerebral stroke and ischemic heart disease. The central retinal artery arises from the ophthalmic artery and its branches supply blood to the inner retina via the superficial capillary plexus. Central retinal artery occlusion (CRAO) is characterized by an obstruction to the central retinal artery that often presents with severe vision loss and a poor prognosis. Branch retinal artery occlusion (BRAO) is defined by a blockage of a branch of the central retinal artery, which typically has a good prognosis if visual acuity is 20/40 or better on presentation. Optical coherence tomography-angiography (OCT-A) is a rapid, highresolution imaging technique that can visualize the microvasculature of the retinal layers, including the superficial and deep capillary plexuses.
Therefore, it is possible to determine the microvascular changes that occur following retinal artery occlusions, and before and after potential therapies that are being actively researched. Therapies under investigation for the treatment of CRAO and BRAO include hyperbaric oxygen, fibrinolysis, and embolysis with laser therapy. In this chapter, the capabilities of OCT-A imaging to visualize and quantify retinal microvascular changes following CRAO and BRAO are assessed. Moreover, the use of OCT-A to understand the benefit of potential therapies is reviewed. 

Keywords: Retinal artery occlusion, Optical coherence tomography angiography, Retinal vascular disease, Retinal ischemia.