When the Light Hurts Your Eyes
Photophobia or light sensitivity is a common eye complaint. It can result from several different conditions and in most cases is easily treatable.
The most common cause of photophobia is inflammation of the anterior region of the eye, which includes the colored iris. The muscular iris controls pupil size and adjusts the amount of light entering the eye. Just as a sore back hurts when you bend it, an inflamed iris muscle painfully constricts when light hits the eye. Even if the injured eye is patched, the light sensitivity continues because light hitting the uninjured eye causes both pupils to constrict.
The treatment for inflammatory light sensitivity is two fold. First we dilate the inflamed pupil with special medications. This chemically paralyses the pupil in the open position so it cannot move. Thus, the pain is reduced because iris movement is minimized. Second, we treat the eye with steroid drops to reduce the inflammation. Significant relief is usually felt within twelve hours.
Another common cause of photophobia is a cataract. When the natural clear lens of the eye becomes cloudy, a cataract has formed. Cataracts tend to scatter light, similar to a frosted window in wintertime. The disrupted image causes discomfort which is perceived as pain. It is not fully understood why this condition results in discomfort. Possibly, the scattered light may cause a brisk, spastic constriction of the pupil which may contribute to the feeling of discomfort. Most likely the feeling is subjective and develops at a higher, emotional level. Fortunately, symptomatic cataracts can be removed with a very high success rate, eliminating the photophobia.
Certain medications and illegal drugs can cause photophobia by simply dilating the pupil and allowing an excessive amount of light to enter the eye. Frequent use of cocaine can cause a chronic dilation of the pupil. This side effect may lead to the inappropriate use of sunglasses.
Occasionally, a patient will complain of light sensitivity, for which no logical explanation can be found. Most of these individuals tend to be fair skinned, with blue eyes. The treatment is the judicious use of tinted glasses to relieve their symptoms.
