What should you know about real red eyes?

Redness occurs when small blood vessels on the eye surface widen. Dryness, smoke, dust, prolonged screen use, allergy and infection can all contribute. Allergic conjunctivitis commonly brings itching and watering, whereas conjunctivitis may also cause discharge or eyelids that stick together. A sharply defined red patch can follow a small surface blood vessel breaking and may look alarming despite little discomfort. Redness with pain or vision change needs a different level of attention.

Do not rub the eye. Rinse away loose irritants with clean water, take breaks from screens and avoid contact lenses until the eye feels normal or a clinician advises otherwise. Do not use someone else’s drops or share eye cosmetics. If itching, discharge or repeated redness continues, arrange an assessment so the cause can be identified rather than masking it with drops.

Seek urgent assessment for severe eye pain, reduced vision, strong light sensitivity, a chemical splash, penetrating injury, a foreign body that will not wash out, or redness in a contact-lens wearer with pain. Sudden changes, a very swollen eye, or redness with severe headache and vomiting also warrant urgent help. Contact a clinician when redness persists, recurs or comes with discharge.

What features point to allergy, infection, dryness or injury? Do I need an examination or drops? When is it safe to wear contact lenses again?