Pink Eye Fact Sheet

Red, gunky eyes are the hallmark of conjunctivitis, a common eye condition. Help keep your eyes clear with this fact sheet.

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If you've ever woken up with an itchy, red, crusty eye, you may have been a victim of pink eye, also known as conjunctivitis. This sticky eye condition is unpleasant, but common, and has a variety of causes. Here's what you need to know to help keep your eyes gunk-free.

What is conjunctivitis?
Conjunctivitis occurs when the clear membrane lining the white part of the eye and the inner part of the eyelid (the conjunctiva) becomes inflamed or irritated. When this happens, the blood vessels feeding the conjunctiva dilate and become larger, which makes the eye appear red. It also commonly results in eye discharge, itchiness or grittiness and mild eye pain.

What causes it?
Pink eye is commonly caused by allergies, bacteria, viruses, an irritant in the eye or, in newborns, a blocked tear duct. 

Viral conjunctivitis is the most common cause. Adenovirus, the same virus that causes the common cold, is frequently to blame. Other viruses that less commonly cause conjunctivitis include herpes simplex virus, varicella-zoster virus, picornavirus, poxvirus and HIV. Viral pink eye usually produces a watery discharge and often affects both eyes, even if it starts only in one.

Bacterial conjunctivitis is more common in children than adults. Bacteria that cause it include staphylococci, streptococci, gonococci, and Chlamydia. Bacterial conjunctivitis tends to cause a thick, yellow, white or green discharge, which can cause your eyelids to feel crusty and welded together, especially in the morning. Bacterial conjunctivitis is more likely to affect one eye, but may spread to the other.

Allergic conjunctivitis usually affects both eyes and is a response to an irritant such as pollen. You may also experience sneezing and watery nasal discharge.

How is it spread?
Viral pink eye is highly contagious and can be spread for 10-12 days after the start of symptoms. You can give it to yourself if you have a cold by coughing or blowing your nose and then touching your eyes. You can also get it from others or even from touching objects contaminated with eye secretions or respiratory droplets of someone who is infected with the virus. You can also spread it from one eye to another. Bacterial conjunctivitis is also highly contagious and usually spreads by touching a contaminated person or surface and then touching the eye. Allergic conjunctivitis is not contagious.