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 Encyclopedia - Photophobia

What causes photophobia?
How is photophobia treated?

Photophobia is an abnormal sensitivity to, and discomfort from, light. A person with photophobia experiences the same sensation in normal light that most people experience when they exit a dark room (such as a theater) into bright sunlight -- pain and discomfort. Unlike persons with normal vision, however, the eyes of persons with photophobia are unable to adapt to changing light conditions.

What causes photophobia?

Photophobia can be a symptom of a variety of diseases or a reaction to any of several different drugs. Any situation that causes the pupil to dilate (enlarge) and allow an excessive amount of light to enter may cause the condition. The most common cause of photophobia is inflammation of the anterior region (front) of the eye, which includes the iris. The iris controls pupil size and adjusts the amount of light entering the eye, and when the muscles of the iris are inflamed, it painfully constricts when light hits the eye.

People with light-colored eyes and those who suffer with migraine headaches experience more light sensitivity and glare, as do individuals who have been diagnosed with albinism, total color deficiency, a central nervous system disorder (such as meningitis), or botulism. Corneal abrasions can also cause light sensitivity, as can uveitis, an inflammation of the inner portion of the eye.

Certain retinal conditions, such as a retinal detachment, are also associated with photophobia. Another common cause is cataracts, a condition that occurs when the eye's natural lens becomes cloudy. The photophobia in this situation is easily eliminated by removing the cataracts.

Some medications and drugs, including some that are illegal, can cause photophobia by causing the pupil to remain dilated for an extended period of time. For instance, frequent cocaine users often wear sunglasses inappropriately.

How is photophobia treated?

The primary symptom of photophobia is the desire to squint or close the eyes when exposed to light. Any light source including sunlight or artificial light will cause the sensitive reaction. Sometimes this light sensitivity is accompanied by headaches.

Because photophobia is a symptom of another disorder, the underlying cause should be diagnosed and treated by a physician. If medication is causing light sensitivity side effects, discontinuing the drug will normally solve the problem. Patients should wear sunglasses with ultraviolet protection and a hat with a brim to decrease the symptoms. Light sources should be shielded to prevent direct light into the eyes, and sources of glare in the environment should be eliminated. Light sensitivity is sometimes a natural defense when the eye has been traumatized whether from an injury, refractive surgery, or other eye conditions. If the light sensitivity is caused by one of these situations, the eye simply needs time to heal.

Left untreated, photophobia can cause very intense pain. If you experience any symptoms, see an eye physician.

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