What should you know about bright red eye?

A sharply defined red patch on the white of the eye can occur when a tiny surface blood vessel leaks; it may look dramatic while causing little discomfort. Redness with discharge, gritty discomfort, or eyelids stuck together can occur with Conjunctivitis. Itching, watering, and symptoms in both eyes can occur with Allergic Conjunctivitis. A painful red eye, light sensitivity, reduced vision, injury, or a visible foreign body needs a different level of assessment. Contact-lens wear also changes the urgency because corneal infection can progress quickly.

Do not rub the eye. Wash your hands, avoid sharing towels, and remove contact lenses until a clinician confirms they are safe to wear. Rinse with clean water if dust or a mild irritant entered the eye; do not try to remove an embedded object. Artificial tears may soothe mild surface irritation, but avoid using someone else's drops or leftover antibiotic treatment. Arrange review if redness persists, recurs, or comes with discharge.

Seek urgent care for severe pain, blurred or reduced vision, halos around lights, strong light sensitivity, injury, chemical exposure, unequal pupils, swelling around the eye, or headache with nausea. Contact-lens wearers should seek prompt assessment for a red or painful eye, particularly when vision changes. Flush a chemical exposure continuously with clean water while obtaining emergency help.

Does the redness involve the surface or deeper parts of the eye? Do I have signs of infection or allergy? Should I stop contact lenses or any eye drops? Which changes mean I need same-day review?