What causes light sensitivity?

Bright light may feel uncomfortable because the surface of the eye is irritated, the eye is inflamed, or the brain is processing light more sensitively. Conjunctivitis can cause redness, watering, discharge, and sensitivity. A small particle or other foreign body in the eye may cause sharp discomfort, watering, and a strong urge to keep the eye closed. Migraine can bring light sensitivity with headache, nausea, or visual symptoms, although the headache may not always be prominent.

Light sensitivity with a severe headache, fever, stiff neck, confusion, or marked drowsiness needs urgent assessment because meningitis can affect the tissues around the brain. The symptom itself does not identify one diagnosis; timing, pain, redness, vision changes, and other symptoms help a clinician narrow the cause.

Rest your eyes in a comfortably dim room and use sunglasses outdoors if they reduce discomfort. Avoid rubbing the eye, and remove contact lenses until symptoms settle or a clinician advises otherwise. If dust, a chemical, or another object may have entered the eye, rinse with clean running water and do not try to pick out an embedded object. Arrange medical advice if symptoms persist, recur, or affect reading, work, or driving.

Seek urgent care for sudden vision loss, severe eye pain, an eye injury, a chemical splash, a very red eye with reduced vision, or light sensitivity with fever and a stiff neck. Contact a clinician promptly if one eye is affected, symptoms are worsening, or there is persistent discharge. A clinician can examine the eye and decide whether testing or treatment is needed.

Ask what findings point to an eye problem, migraine, or another cause; whether contact lenses or medicines could be contributing; what symptoms should trigger urgent review; and how to protect your eyes while they recover.