Causes

Understanding Red Eye: Causes

Choose a preferred language

Do your eyes sometimes get red and irritated? This could be a sign of irritation or infection. The inside of your eyelid and the white of your eye are covered with a membrane called the conjunctiva. When your eye is irritated or infected, the blood vessels in this membrane swell. This condition is called conjunctivitis. It is also called red eye or pink eye.

Front view of eye showing red eye.


Irritation

Allergies and environmental irritants are common causes of inflamed eyes. Other causes can include:

  • Injuries

  • Objects in the eye

  • Some eye drops

  • Makeup

  • Contact lenses

  • Eye diseases

  • Eye fatigue


Infection

Viruses and bacteria can cause eye infections. An infection may begin in your eye. It can also start somewhere else in your body, such as your nose or throat. Sexually transmitted infections can also cause eye infections.

Online Medical Reviewer: Chris Haupert MD

Online Medical Reviewer: Raymond Kent Turley BSN MSN RN

Online Medical Reviewer: Rita Sather RN

Date Last Reviewed: 09/01/2025

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

FPC Locations

FPC Locations

Find a Provider

Find a Provider

Our Services

Our Services

Patient Portal

Patient Portal
Related Articles
Read article
Eye Care
Fourth Nerve Palsy

The fourth cranial nerve controls the actions of one of the external eye muscles. It can be damaged by disease or injury. The condition usually affects only one eye.

Read article
Eye Care
Eye Exposure, Chemical

If a chemical comes in contact with the eye, it is very important to flush it out as quickly as possible. The effects of a chemical exposure can range from mild irritation to permanent scarring and vision loss.

Read article
Eye Care
Understanding computer vision syndrome

CVS is very common. Your eyes may itch and tear, or be dry and red. You may not be able to focus well. These problems are the result of a lot of computer use.

Read article
Eye Care
Conjunctivitis, Allergic

Allergic conjunctivitis is caused by an allergen. Symptoms may include redness of the eye, swelling, fluid leakage, and itching or burning.