Red eye

Date Updated: 03/10/2023

Definition

Red eye is a common problem that can happen in one or both eyes. The redness comes from the blood vessels on the surface of the eye. These blood vessels expand or dilate due to irritation or disease.

Causes

Allergies
Blepharitis (which is eyelid inflammation)
Chalazion or stye, which comes from inflammation in the glands of your eyelid
Complication from a recent eye surgery
Contact lens complication
Corneal abrasion (scratch): First aid
Corneal herpetic infection or herpes
Corneal ulcer
Dry eyes (caused by decreased production of tears)
Ectropion (a condition in which the eyelid turns outward)
Entropion (a condition in which the eyelid turns inward)
Episcleritis, which is inflammation of the covering of the white part of the eye
Eye drops side effect or complication
Floppy eyelid syndrome, which happens when the eyelid can easily fold on itself
Foreign object in the eye: First aid
Glaucoma (which is a group of conditions that damage the optic nerve)
Hay fever (allergic rhinitis)
Injury, such as from a blunt trauma or a burn
Iritis (which is inflammation of the colored part of the eye)
Keratitis (which is inflammation of the cornea)
Orbital cellulitis, which is an infection of the area around the eye
Pink eye (conjunctivitis)
Scleritis (which is inflammation of the white part of the eye)
Subconjunctival hemorrhage (broken blood vessel in eye)

When to see a doctor

Seek immediate medical care if:

Your eyesight changes suddenly.
Red eye happens with a bad headache, eye pain, fever or if light starts to hurt your eyes.
You also have an upset stomach or are throwing up.
Red eye is caused by an object or chemical splashed in your eye.
You suddenly begin to see circles around lights.
You feel as if something is in your eye.
You have swelling in or around your eye.
You cannot open or keep your eye open.

Make an appointment with a health care provider

Sometimes, having red eye for a short time is not a reason to worry. If you think the redness is caused by an over-the-counter eye drop, try a different brand or take a break from using them.

Call your health care provider for an appointment if you have red eye that doesn't clear up after several days, especially if you have thick pus or mucous for a long time.

Contact your eye surgeon if:

You're having eye redness with pain.
You've had eye surgery or an eye injection in the past.