What should you know about people with red eyes?

Redness happens when small blood vessels on the surface of the eye become more visible or irritated. Allergy may cause itching and watering; conjunctivitis may cause redness with discharge and can spread between people depending on its cause. Dryness, dust, contact-lens irritation, or a small surface blood vessel can look different again. A red eye is a symptom rather than a diagnosis, and a person may need an examination when pain, light sensitivity, or visual change is present.

Avoid rubbing the eye and wash your hands often, especially if there is discharge. Remove contact lenses and do not wear them again until a clinician says it is suitable. A clean cool compress may ease irritation. Do not share towels, pillows, eye cosmetics, or eye drops. Seek advice before using leftover or borrowed antibiotic or steroid drops, because the wrong product can mask a serious problem or worsen infection. Use the red eye and conjunctivitis information to compare patterns safely.

Get urgent eye care for severe pain, reduced or blurred vision, marked light sensitivity, a chemical splash, an embedded object, significant injury, or redness with headache and nausea. Contact-lens wearers with pain or visual change need prompt assessment. Same-day advice is sensible when thick discharge is worsening, the eyelids are very swollen, or symptoms are not settling. Call emergency services for sudden major loss of vision or a serious eye injury.

Ask what is causing the redness, whether you should stop lenses or eye cosmetics, whether treatment is needed, and which changes should trigger an urgent review.