Definition

By Mayo Clinic staff

Pink eye (conjunctivitis) is an inflammation or infection of the transparent membrane (conjunctiva) that lines your eyelid and covers the white part of your eyeball. When small blood vessels in the conjunctiva become inflamed, they’re more visible. This is what causes the whites of your eyes to appear reddish or pink.

Pink eye is commonly caused by a bacterial or viral infection, an allergic reaction, or — in babies — an incompletely opened tear duct.

Though pink eye can be irritating, it rarely affects your vision. Treatments can help ease the discomfort of pink eye. Because pink eye can be contagious, early diagnosis and treatment can help limit its spread.

Symptoms

The most common pink eye symptoms include:

• Redness in one or both eyes
• Itchiness in one or both eyes
• A gritty feeling in one or both eyes
• A discharge in one or both eyes that forms a crust during the night that may prevent your eye or eyes from opening in the morning
• Tearing

When to see a doctor
Make an appointment with your doctor if you notice any signs or symptoms you think might be pink eye. Pink eye can be highly contagious for as long as two weeks after signs and symptoms begin. Early diagnosis and treatment can protect people around you from getting pink eye too.

People who wear contact lenses need to stop wearing their contacts as soon as pink eye symptoms begin. If your symptoms don’t start to get better within 12 to 24 hours, make an appointment with your eye doctor to make sure you don’t have a more serious eye infection related to contact lens use.

In addition, there are other serious eye conditions that can cause eye redness. Typically, these conditions will also cause pain and blurred vision. If you experience these symptoms, seek urgent care.

http://www.mayoclinic.com/health/pink-eye/DS00258