Health Topics A-Z

What Is Conjunctivitis?

The conjunctiva — the thin, transparent membrane that lines your eyeball and your eyelid — can become inflamed for various reasons. Most cases of conjunctivitis run a predictable course, and the inflammation usually clears up in a few days.

Conjunctivitis, commonly known as 'pinkeye,' is a common disease, especially in children. Conjunctivitis is painless. Although conjunctivitis 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 conjunctivitis usually infects both eyes and produces a heavy discharge of pus and mucus.
• Viral conjunctivitis typically begins in one eye, causing copious tears and a watery discharge. Within a few days the fellow eye becomes involved. A swollen lymph node may be felt just in front of the ear.
• Allergic conjunctivitis produces tearing, itching and redness in the both eyes, and sometimes an itchy, runny nose.
• Ophthalmia neonatorum is a severe form of bacterial conjunctivitis 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 conjunctivitis; it is most frequently associated with the long-term use of contact lenses.

What Causes Conjunctivitis?

Conjunctivitis is caused by an irritant.  It could be a bacterial or viral infection, a chemical exposure, or a reaction to eye drops.  Conjunctivitis can also be caused by an allergic reaction to pollen, smoke, or other material that irritates your eyes.  Children sometimes contract conjunctivitis after a cold or a sore throat.

Viral conjunctivitis is easily spread from person to person. Viruses strains that most frequently cause conjunctivitis include:

• Adenovirus, which often causes the common cold.
• Herpes viruses, which cause chickenpox, shingles or cold sores on the lips.
• Corona viruses.

Gonorrhea, a sexually transmitted disease, is the most important form of bacterial conjunctivitis.  Another sexually transmitted disease, chlamydia, can cause conjunctivitis 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.

iant papillary conjunctivitis is thought to be an allergic reaction to the presence of a chronic foreign body.  It is most frequently encountered in folks wearing hard contact lenses and those who have an artificial eye (ocular prosthesis).