Eye red, painful and sensitive to light: what to know

Redness may come from surface irritation, dryness, a small foreign body, or inflammation of the tissues around the eye. Conjunctivitis can cause redness, watering, discharge and soreness; allergic conjunctivitis often causes itching and may affect both eyes. Pain and light sensitivity deserve extra attention, particularly when vision is blurred or the pain feels deep rather than gritty.

The pattern, speed of onset and any exposure help a clinician narrow the cause. Contact lens wear, an eye injury, chemical splash, recent eye procedure, severe headache or reduced vision changes the level of concern.

Stop wearing contact lenses and avoid eye makeup until the eye has recovered or a clinician has advised you. Do not rub the eye. If dust may be present, rinse gently with clean lukewarm water; do not try to remove an embedded object. Rest in dim light and use sunglasses outdoors if they make you more comfortable.

Do not use leftover antibiotic or steroid eye drops, because the wrong drop can worsen some eye conditions or hide important changes. Arrange medical advice promptly when pain and light sensitivity persist, recur, or affect normal activities.

Seek urgent assessment for reduced or blurred vision, severe or increasing pain, marked light sensitivity, a cloudy-looking cornea, unequal pupils, swelling around the eye, nausea with eye pain, or an injury or chemical exposure. Get emergency help if vision suddenly changes or the eye has been pierced. A red eye in a contact lens wearer also needs prompt review because infection can progress quickly.

Ask what part of the eye appears inflamed, whether your vision and eye pressure need checking, and whether contact lenses or an injury could be contributing. Ask which drops are suitable, how long to avoid lenses, and which change should bring you back sooner.