Central Retinal Artery Occlusion - Color Fundus Photograph, Example #2
Most cases of central retinal artery occlusion are caused by emboli from the carotid artery or the heart valves. The embolus blocks the central retinal artery and reduces blood flow to a variable extent to the retina. In this photograph, the blood flow was severely impaired as evidenced by the "boxcarring" of the blood column (yellow arrow). Inadequate blood supply causes the retina to lose its transparency, so-called ischemic retinal whitening (green arrow). The fovea is thinner and does not turn white, hence the origin of the term "cherry red spot" that is a classic sign of this disease (blue arrow).