Photophobia, or light sensitivity, is an abnormal response to light in which the sufferer experiences an aversion to light accompanied by aching eye pain. Numerous ocular conditions can produce light sensitivity, most notably uveitis, glaucoma, and keratitis. A variety of medications may also cause patients to experience sensitivity to light. Photophobia may also happen secondary to several neurological abnormalities, including migraine and meningitis. The treatment for light sensitivity depends on the underlying cause of the condition.
Uveitis is one of the most frequent causes of light sensitivity. Resulting from inflammation in the blood vessel lining of the eye, uveitis is characterized by redness, ocular pain, headache, and pronounced light sensitivity. Uveitis can be the result of trauma, surgery, or an underlying systemic disease, such as lupus, rheumatoid arthritis, or ankylosing spondylitis. Physicians who see patients with anterior uveitis, also known as iritis, and posterior uveitis routinely perform blood tests, chest x-rays, and other tests to determine if a patient with uveitis has an associated disease. In addition to treating any related illnesses, physicians treat uveitis with topical, injected and oral steroids, nonsteroidal anti-inflammatory medications, and dark eyeglasses.
Keratitis is an infection of the cornea, which is the transparent window on the front of the eye. When the cornea is infected or traumatized, the patient often experiences light sensitivity. Bacteria and viruses, including herpes simplex virus, may cause ulcers on the cornea. Patients treat keratitis by using antibiotic or antiviral drops directed at the infectious agent causing the problem. Scratches or burns of the cornea and contact lens overuse may also lead to light sensitivity.
Several drugs increase the ocular response to light by dilating the pupil, which allows too much light to enter the eye. Amphetamines, methamphetamine (crystal meth), and cocaine all cause pupil expansion after use. Pharmacologic drops used in an eye doctor's office for pupil dilation include mydriacyl, cyclopentolate, atropine, and phenylephrine. Scopolamine patches, used to prevent sea sickness and motion sickness, will also produce light sensitivity through excessive pupil dilation. Chemotherapy drugs, antibiotics, birth control pills, and some acne medications may also increase the body's response to light.
Migraines are periods of abnormal brain activity due to reduced blood flow to a brain region secondary to spastic closure of the blood vessel. Migraine sufferers frequently complain of a throbbing headache that is often accompanied by nausea, vomiting, hypersensitivity to sound, and light sensitivity. Many migraine patients also report visual disturbances that precede the onset of the headache. Common triggers for migraine include hormonal fluctuations, alcohol, caffeine, chocolate, monosodium glutamate, and exposure to bright lights. Treatments for migraine include avoidance of known triggers, beta-blockers, antidepressants, triptans, and botulinum injections.