Red eye is a common problem that can affect one or both eyes. The redness associated with red eye comes from expanded blood vessels on the surface of your eye due to inflammation, usually from some form of irritation or infection.

Most often the inflammation that causes red eye occurs in the membrane covering the white of your eye and lining your eyelid. This membrane is called the conjunctiva (kun-JUNK-tih-vuh); inflammation of the conjunctiva is called conjunctivitis (kun-junk-tih-VY-tis).

"Pink eye" is a term commonly used to describe red eye and refers to both viral and bacterial infections of the conjunctiva (conjunctivitis). It can also have other causes, such as allergy.

Pink eye caused by a virus may involve clear discharge or some amount of pus and mucous discharge.

Pink eye caused by bacteria is more common in children than adults and may involve a more continuous and thicker discharge of pus and mucus.

1. Pink eye (conjunctivitis)

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

Source: mayoclinic.org

Seek immediate medical attention if red eye is accompanied by:

• Vision loss
• Severe headache, eye pain, nausea or unusual sensitivity to bright light
• Inability to open your eye or keep your eye open
• A sensation that there's something in your eye

For persistent red eye that doesn't clear up after several days, especially if you have a thick or nearly continuous pus or mucous discharge, contact your doctor for an appointment.

Source: mayoclinic.org