Pink eye is a commonly used term for conjunctivitis, an inflammation of the conjunctiva, the thin membrane that covers the front of the eyeball and the lower eyelid. Conjunctivitis is very easily spread, especially among children, and can be caused by bacteria, viruses or allergies. The symptoms vary slightly depending on the type of infection. Most cases of conjunctivitis are caused by viruses or allergies.
Redness
Pink eye causes the capillaries, the tiny blood vessels in the eye, to become inflamed and more prominent. This gives the eye its characteristic pink appearance. The entire eye has a shiny, glassy look. In most cases, only one eye is affected at first, but the infection can spread to the other eye.
Discharge
People with pink eye have a mucousy discharge from the eye. This can be copious enough to stick the eyelids together, especially first thing in the morning. The secretions from bacterial infection are thicker and more likely to be yellow or green, according to the Mayo Clinic, while viral conjunctivitis and allergic conjunctivitis produce a more watery discharge. The discharge from bacterial conjunctivitis is also more likely to last throughout the day, according to Deborah Jacobs, M.D.
Other Symptoms
Conjunctivitis can cause the eye to become scratchy and itchy, especially in cases of allergic conjunctivitis. Sometimes eyelids become swollen. Pink eye can also make the eye very sensitive to bright light. Vision loss is not common with pink eye, although vision may be blurry if large amounts of discharge are being produced, according to the Merck Manual. When the secretions are wiped away, the blurred vision should improve. Allergic conjunctivitis can also cause what appear to be clear blisters on the surface of the eye, according to the Mayo Clinic.
