Dismiss Modal

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.

© 2000-2025 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.

Make an Appointment

Make an Appointment

Find a Doctor

Find a Doctor

Find a Location

Find a Location
Related Articles
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
How the Eye Works

Sharp vision depends on many factors. The parts of the eye work together to bend (refract) and focus light rays.

Read article
Eye Care
Eyeglasses and Contact Lenses

Eyeglasses are the most common form of eyewear used to correct or improve many types of vision problems. Contact lenses are worn directly on the cornea of the eye.

Read article
Eye Care
Anatomy of the Eye

The structures of the eye include the cornea, iris, pupil, macula, retina, and the optic nerve.