What should you know about red eye in photos?

A flash can illuminate blood-rich tissue behind the pupil, creating a red reflection in the image. This is different from visible redness on the white of the eye. If one eye repeatedly appears different in photographs, especially without flash, arrange an eye examination so the pupil, cornea and retina can be checked. A photograph alone cannot diagnose an eye problem.

Visible redness may occur with dryness, irritation, a broken surface blood vessel or conjunctivitis. Allergies commonly cause itching and watering; infection may bring discharge or eyelids sticking together. These patterns are described in [Conjunctivitis](/conditions/conjunctivitis/) and [Allergic Conjunctivitis](/conditions/allergic-conjunctivitis/).

Compare photographs taken in different lighting, but do not rely on repeated pictures as a screening test. Avoid rubbing the eyes, sharing towels or using someone else’s eye drops. Remove contact lenses if the eye feels irritated. Preservative-free lubricating drops may soothe mild dryness when suitable for you; a pharmacist or clinician can help choose an option. See the [Red Eye](/symptoms/red-eye/) guide for symptom-focused care.

Seek urgent medical care for eye pain, reduced or blurred vision, marked light sensitivity, an injury, chemical exposure, a new irregular pupil, or redness in a contact-lens wearer. Prompt assessment is also sensible when redness is persistent, keeps returning, or comes with significant discharge or swelling.

Ask whether the image shows a flash reflection or true eye redness, whether your vision and eye pressure need checking, and which symptoms should prompt urgent review. Mention when the photographs were taken, whether one eye is consistently affected, contact-lens use, pain, discharge and any recent injury.