This term applies to any condition causing redness and inflammation of the conjunctiva.

There are three common types:

1. Infective conjunctivitis

Caused by a bacterial or viral infection; can be contagious. The whites of the eyes will look pink and the eyelids may be red and swollen (see picture).

Sufferers may also complain of a sticky, yellow coating or discharge on the eyelashes upon waking. One or both eyes may be affected.

2. Allergic conjunctivitis

Symptoms occur because of an allergic reaction to pollen, dust mites, animal dander, etc. Both eyes are usually affected. Sufferers will complain of watery, itchy eyes and there may be a stringy discharge.

3. Irritant conjunctivitis

Caused by contact with substances that irritate the conjunctiva (e.g. shampoo, chlorinated water, smoke). Eyes will look red and feel tired, sore or irritated (see picture, right). Symptoms tend to resolve once the irritant is removed.