One eye red, sore and sensitive to light

Surface irritation, a small scratch, contact-lens trouble, or conjunctivitis can cause redness and discomfort. Inflammation deeper in the eye can also make light feel painful. A blocked or infected eyelid gland may add tenderness, but marked light sensitivity is a reason not to assume this is simple irritation. The pattern, speed of onset, discharge, and effect on sight help a clinician decide what needs examination.

Remove contact lenses and do not wear them again until a clinician says it is safe. Avoid rubbing the eye, sharing towels, or using someone else’s drops. Sunglasses may make bright surroundings more comfortable, but they do not treat the cause. Arrange prompt medical advice and mention any injury, chemical exposure, recent eye procedure, or reduced vision.

Seek urgent care if pain is severe, vision is blurred or reduced, the eye looks cloudy, the pupil looks unusual, or headache, nausea, vomiting, fever, or swelling around the eye occurs. A chemical splash needs immediate rinsing with clean running water while emergency help is arranged. Do not delay if symptoms began after an injury or while wearing contact lenses.

Ask whether the surface of the eye is scratched, whether an infection or inflammation is present, and whether you should stop contact lenses or any current eye drops. Ask which changes in vision or pain should send you back urgently.