The primary symptom of retinal artery occlusion is a sudden, painless, persistent, substantial loss of vision in one eye. In about 10% of those affected, this loss of vision is preceded by one or more episodes of a condition called amaurosis fugax. Amaurosis fugax is a temporary episode of decreased vision, usually lasting no more than 10 to 15 minutes, that is sometimes described as "closing a curtain" on one eye.
Although retinal vein occlusion also causes painless loss of vision, this vision loss sometimes develops gradually over several days or weeks rather than suddenly. Also, depending on the extent of retinal damage, some people have only minimal blurring of vision, while others have more substantial vision loss.