Why does dry eye cause red eye?

Tears keep the front of the eye smooth and reduce friction between the eyelid and eye surface. When the tear film is unstable, the eye may respond to irritation with visible redness, burning, a gritty feeling or watering. Red Eye is a common presentation of Dry Eye, but redness can also follow allergy, infection, an eyelid problem, a contact-lens issue or an injury.

Dry air, long periods of focused screen work, smoke and wind can aggravate symptoms. One eye may look redder than the other depending on exposure or how the tear film behaves.

Give your eyes regular breaks from screens, blink fully and keep away from direct fan or air-conditioner flow. Avoid smoke and do not rub the eye. Lubricating drops can be useful for dryness; a pharmacist or eye-care professional can help select one. Redness-relief drops work differently and may not address the underlying dryness.

Take out contact lenses if redness or discomfort develops. Do not use another person's drops, and avoid eye makeup until irritation has settled or you have received advice.

Seek urgent assessment for severe pain, reduced or suddenly changed vision, light sensitivity, an injured eye, chemical exposure, or a red eye while wearing contact lenses. Arrange a non-urgent review if redness persists, frequently returns, or is accompanied by discharge or eyelid swelling.

Is dryness the likely contributor, or should allergy, infection or eyelid disease be checked? Are my lenses, drops or medicines aggravating the problem? How should I use lubricating drops safely?