Sudden vision loss can occur for a number of reasons, and most causes of sudden vision loss are painless. These can include stroke, brain tumors, injuries to the brain, retinal detachment, and wet macular degeneration. Clots and venous blockages in the eye can also contribute to sudden vision loss.
Retinal vein occlusion and retinal artery occlusion are two causes of vision loss related to circulatory problems in the eye. Retinal artery occlusion generally occurs when a blood clot blocks blocks one of the arteries supplying blood to the retina of the eye. Permanent vision loss can occur if retinal artery occlusion isn't treated right away. Most physicians believe emergency care is necessary to prevent permanent retinal damage.
Retinal vein occlusion occurs when the central retinal vein, which helps move deoxygenated blood back to the lungs and heart, becomes blocked. This type of occlusion normally has causes other than embolism, and only about one-third of patients recover their normal vision with treatment.
Amaurosis fugax is an eye condition most often found in geriatric patients suffering from vascular disorders. Amaurosis fugax causes tiny blood clots to block the blood vessels inside the eye. These clots often break up on their own, restoring vision. Persons with this disorder, however, are at an increased risk for stroke and more serious ocular occlusion.
Retinal detachment can cause sudden vision loss, though often, the vision loss associated with retinal detachment occurs slowly, over a period of a few days. Persons who experience trauma-related retinal detachment may experience more sudden vision loss.
Strokes, tumors, and other neurological conditions can cause sudden vision loss if they damage the part of the brain responsible for interpreting visual signals. Vision loss related to neurological disorders may not be total. Patients may experience blind spots, or they may lose peripheral vision. Some patients experience loss of inside or outside fields of vision in both eyes.
A macular hole, or degeneration of the part of the retina responsible for central vision, can cause sudden vision loss. Physicians do not yet understand all of the causes of macular holes, but hemorrhages within the eye have been implicated. The vision loss associated with this condition is generally not total, but may create blind spots in the center of a patient's vision. Both eyes may be affected, though experts do not yet understand why.
Hemorrhages within the eye, whether or not they are associated with permanent damage to the structures of the eye, can cause sudden vision loss. Certain conditions, including retinal tears, macular degeneration, or diabetes, can increase the risk of such hemorrhages.
Injuries to the cornea can also cause sudden vision loss. Such injuries are typically painful, and most patients are able to connect vision loss with corneal injury even before seeking medical treatment.