Final answer:
The #1 cause of retinal artery occlusion is arteriosclerosis, which is the hardening and narrowing of the arteries due to the build-up of plaque.
Step-by-step explanation:
The #1 cause of retinal artery occlusion is arteriosclerosis, which is the hardening and narrowing of the arteries due to the build-up of plaque. Arteriosclerosis can damage the endothelium of an artery, making it more prone to injury. Factors such as high blood pressure, high blood glucose, tobacco use, and high blood lipids can contribute to the development of arteriosclerosis.