Blindness is not only caused by a wide variety of disorders, it comes in a variety of shapes and sizes. Temporary blindness can be caused by several different underlying issues -- and is often a symptom, rather than a syndrome. Here’s a look at temporary blindness.
Transient Vision Loss
Transient vision loss is, literally, the loss of vision. It may last from only a few seconds up to several hours. In most cases, there is an identifiable cause, usually an underlying disorder, whether neurological or cardiovascular in origin. Thromboembolisms, or clots that break loose and travel around the blood stream, can be responsible for vision loss. The blood vessels in the eyes are extremely small, and although rare, it is possible for larger clots to lodge in that area and cut off vision temporarily. Issues with the heart, such low blood pressure, arrhythmias in the heart, or anemia may also be responsible. More serious concerns, like brain tumors or epilepsy, can also be at the root of the problem.
Amaurosis Fugax
Other disorders are characterized by temporary loss of vision. Amaurosis fugax, or episodic blindness, occurs when there is an interruption in the blood flow to the retina. The retina is a layer of the eyeball, located near the back, filled with photosensitive cells (rods and cones) that filter light before the information is sent through the optic nerve to centers in the brain responsible for vision. Generally, this interruption is because of clots or plaque (a substance that forms in the blood vessels made of calcium, fat, and other debris) that form in larger blood vessels and wind up in the smaller vessels of the eye, creating a sort of dam. Generally, the vision loss affects only one eye at a time and lasts no more than a few minutes. It may seem as if a dark shadow descends over the eye. More serious neurological issues can follow, as this is often a forerunner of a stroke.
Flash Blindness
Flash blindness is extremely common and occurs to almost everyone at some point. The most relatable scenario is that of getting your picture taken in a dark room. When the flash goes off, it floods the eyes with light, taking them out of near darkness and then quickly returning them. Basically, the retina gets over saturated because when the pupils are dilated to take in more light in a dark setting they do not have time to shrink and re-expand normally.
Conversion Disorder
Conversion disorder, or functional neurological symptom disorder, used to be called “hysterical blindness.” However, blindness isn’t the only characteristic symptom of conversion disorder. Conversion disorder is a psychological disorder in which a stressful event transcends from psychological stress and becomes a physical construct. The senses are those most often affected. When vision issues are the result, your sight may grow blurry or darkened, or you may see double. If you have recently experienced a stressful event, seek medical care. If your doctor finds no physical reason for episodes of temporary blindness, counseling may be beneficial.
Sudden Vision Loss
Complete vision loss in one or both eyes can be the result of a few other things, but should be considered an emergency. The retina can become torn or detached, interfering with the passage of visual information to the optic nerve. The macula, a small spot in the retina responsible for clear central vision, can also become damaged and make it difficult to see detail, such as small print or familiar faces. Injury or untreated infection can cause corneal opacity, or a clouding of the normally clear protective lens on the outside of the eye. Chemical burns, scratches, and radiation as a result of extensive amounts of light off reflective surfaces (snow blindness) can all damage the corneas. Vitreous hemorrhage occurs when blood leaks into the jelly-like substance i the eye, preventing light from passing through normally. Additionally, pressure in the brain (such as that brought on by traumatic head injuries) can also cause blindness, suddenly or temporarily. Fluids can build up around the skull, putting pressure on the parts of the brain and nerves responsible for vision.
Temporary blindness, whether sudden and complete or occasional and short-lived should not be taken lightly. Seek medical attention immediately if you have experienced vision loss.
