This term describes a group of diseases that cause swelling, itching, burning, and redness of the conjunctiva, the protective membrane that lines the eyelids and covers exposed areas of the sclera, or white of the eye. It is caused by a virus which is very contagious and spreads easily. The virus may affect one or both eyes. At its onset, conjunctivitis is usually painless and does not adversely affect vision but can be uncomfortable. The body’s defenses will clear viral conjunctivitis in one to three weeks, and medication is not always necessary. Cold compresses several times a day on the eyes may offer relief as may artificial tears and dark sunglasses.

But for some forms of conjunctivitis, treatment will be needed. If treatment is delayed, the infection may worsen and cause corneal inflammation and a loss of vision.