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.

© 2000-2026 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.

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
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
Understanding Color Blindness

Your retina has special cells that detect color. If you have a problem with these cells, you may not be able to see some colors.

Read article
Eye Care
Cataracts

A cataract is a clouding of the lens of the eye. This is an area that is normally clear. Cataracts can cause cloudy or blurry vision.