My eye has been red for a week: what should I do?

Redness happens when small blood vessels on the eye surface widen or become irritated. Allergic conjunctivitis often causes itching, watering and redness, sometimes in both eyes. Conjunctivitis may cause gritty discomfort, watering or sticky discharge and can spread between people. Dryness, smoke, dust, contact lenses or rubbing can also irritate the surface. The duration alone cannot identify the cause, so an examination matters when redness has not settled.

Do not rub the eye. Wash your hands, avoid sharing towels, pause contact lens use, and discard eye makeup used during the episode. A cool clean compress may soothe irritation. Avoid using another person’s drops or leftover antibiotic or steroid drops; the wrong product can delay diagnosis or worsen some eye problems. Arrange a medical or optometry review because the redness has persisted for a week, and mention any discharge, exposure or injury.

Seek urgent eye care for moderate or severe pain, reduced or blurred vision, marked light sensitivity, a severe headache with nausea, injury or chemical exposure, a bulging eye, or swelling that makes eye movement difficult. Contact lens wearers with redness or pain should seek prompt advice. Flush a chemical exposure with clean running water while obtaining emergency help.

Is the redness on the surface or deeper in the eye? Could allergy, infection, dryness or contact lenses explain it? Should I use any drops, and when can I resume lenses? What changes should trigger urgent review?