Eye infections occur when bacteria, viruses, or fungi invade the eye or surrounding tissues, leading to irritation, redness, and discomfort. They can affect different parts of the eye, including the eyelids, conjunctiva (the thin membrane covering the white of the eye), or cornea. Eye infections are common and usually mild, but in some cases, they can lead to complications if not treated properly.

Common types of eye infections include conjunctivitis (often called pink eye), which causes redness, watering, and sticky discharge, and blepharitis, an inflammation of the eyelids that makes them swollen or crusty. More serious infections, such as keratitis or uveitis, affect deeper parts of the eye and can cause pain, blurred vision, or light sensitivity.

Symptoms vary depending on the cause but often include redness, itching, swelling, discharge, and a gritty or burning feeling. Viral infections usually cause watery discharge, while bacterial ones often produce thicker, yellow or green discharge. Allergic reactions can mimic infections but are not contagious.