How can arteriosclerosis cause sudden loss of vision from a blocked retinal artery?

In arteriosclerosis, degenerative processes cause the walls of arteries to thicken and harden, which narrows the vessel lumen and reduces blood flow. This condition can lead to a sudden and profound loss of vision if the central retinal artery—the vessel responsible for supplying blood to the inner retina—becomes completely occluded.12

The blockage occurs because the thickening of arterial walls restricts the passage of blood, and in some cases, the formation of fatty plaques or associated blood clots can result in a total obstruction of the vessel. When this supply of oxygenated blood to the retina is cut off, the resulting ischemia causes immediate and severe vision loss. Unless the obstruction is relieved promptly, this damage to the retina is typically permanent.12