Conjunctivitis is the inflammation of the conjunctiva (the membrane that lines the eyelids and covers the exposed surface of the eyeball).
Conjunctivitis can be caused by allergies, bacteria, viruses, chemicals, or underlying health conditions.

Conjunctivitis, commonly known as pink eye, is an infection of the conjunctiva (the outer-most layer of the eye that covers the sclera). It is a fairly common condition and usually causes no danger to the eye or your child's vision. Often called "pink eye," it is an inflammation of the conjunctiva, the tissue that lines the inside of the eyelid. Inflammation causes small blood vessels in the conjunctiva to become more prominent, resulting in a pink or red cast to the whites of your eyes.

Acute conjunctivitis is redness and soreness (inflammation) of the clear covering (the conjunctiva) which coats the white of the eye and lines the inside of the eye lids. Conjunctivitis can be caused by a virus, bacteria, irritating substances (shampoos, dirt, smoke, and especially pool chlorine), allergens (substances that cause allergies) or transmitted diseases (STDs). Pink eye caused by bacteria, viruses, and STDs can spread easily from person to person, but is not a serious health risk if diagnosed promptly.

Causes

One cause involves the introduction of either bacterial or viral microorganisms into the eye. These may be transmitted to the eye by contaminated hands, washcloths or towels, cosmetics (particularly eye makeup), false eyelashes or extended wear contacts.

Minor conjunctivitis can accompany a viral cold or flu. Although bacterial and some of the viral infections (particularly herpes) are not very common, they are potentially serious. Both types of infection are contagious.

Symptoms

Symptoms of conjunctivitis can range from mild to serious. The symptoms are due to release of histamine and other active substances by mast cells , which stimulate dilation of blood vessels. In acute bacterial conjunctivitis, the infection usually lasts only 2 weeks. The patient typically complains of burning and the sensation of a foreign body in his eye.

The common symptoms include the eyes turning red, irritation and pain. Depending on the causes the symptoms differ slightly.
Pink eyes due to bacterial and virus infections will lead to red eyes that are watery and often discharge of fluid occurs. This starts in one of the eyes and spread to the other and both the eyes will be affected very soon. Infectious pink eyes are highly contagious.

Treatment of Conjunctivitis

1.Conjunctivitis sometimes requires medical attention. Cool compresses and artificial tears sometimes relieve discomfort in mild cases.

2.In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Some patients with persistent allergic conjunctivitis may also require topical steroid drops.

3.Bacterial conjunctivitis is usually treated with antibiotic eye drops or ointments that cover a broad range of bacteria (chloramphenicol or fusidic acid used ).

Antibiotic medication, usually eye drops, is effective for bacterial conjunctivitis. Viral conjunctivitis will disappear on its own. Many doctors give a mild antibiotic eyedrop for pink eye to prevent bacterial conjunctivitis.
A decoction prepared with a handful of dried coriander in 60 ml of water is an excellent eye-wash in conjunctivitis. It is said to relieve burning and reduces pain and swelling. This decoction should, however, be sparingly used by persons suffering from bronchial asthma and chronic bronchitis.