Eye Health Center
Understanding Pink Eye -- the Basics
What Is Pink Eye?
Pink eye (or conjunctivitis) occurs when the conjunctiva -- the thin, transparent membrane that lines your eyeball and your eyelid -- becomes inflamed for various reasons. Most cases of pink eye run a predictable course, and the inflammation usually clears up in a few days.
Pink eye is a common disease, especially in children. Although pink eye can be highly contagious (known to spread rapidly in schools or daycare settings), it is rarely serious and will not damage your vision if detected and treated promptly.
- Bacterial pink eye usually infects both eyes and produces a heavy discharge of pus and mucus.
- Viral pink eye typically begins in one eye, causing lots of tears and a watery discharge. Within a few days the other eye becomes involved. A swollen lymph node may be felt just in front of the ear. This is probably the most contagious form of pink eye.
- Allergic pink eye produces tearing, itching, and redness in the both eyes, and sometimes an itchy, runny nose.
- Ophthalmia neonatorum is a severe form of bacterial pink eye in newborn babies. It must be treated immediately by a doctor to prevent permanent eye damage or blindness.
- Giant papillary conjunctivitis is another form of pink eye. It is most frequently associated with the long-term use of contact lenses.
What Causes Pink Eye?
Pink eye is caused by an irritant. It could be a bacterial or viral infection, a chemical exposure, or a reaction to eye drops. Pink eye can also be caused by an allergic reaction to pollen, smoke, or other material that irritates your eyes. Sometimes pink eye appears after a cold or a sore throat.
Viral pink eye is easily spread from person to person. Virus strains that most frequently cause pink eye include:
- Adenovirus, which often causes the common cold
- Herpes viruses, which cause chickenpox, shingles, or cold sores
Gonorrhea, a sexually transmitted disease, is the most important form of bacterial conjunctivitis and it can lead to vision loss if left untreated. Another sexually transmitted disease, chlamydia, can cause conjunctivitis in adults and also in newborns when the disease is passed to the child from its mother.
Ophthalmia neonatorum may occur if the infant is exposed to pathogens when passing through the birth canal of a mother infected with chlamydia or gonorrhea.
Giant papillary conjunctivitis is thought to be an allergic reaction to the presence of a chronic foreign body. It is most frequently encountered in people wearing soft contact lenses and those who have an artificial eye (ocular prosthesis).
WebMD Medical Reference
