At some time, most of us have had sore eyes. This is distressing but, fortunately, is usually not serious. The most common cause is conjunctivitis, an inflammation of the clear covering of the white of the eyes.

This may be due to infection, either with bacteria or viruses, or it may be due to an allergy as, for example, occurs in hay fever.

Bacterial infections usually cause a discharge of very sticky pus. Often the eyelids are hard to open in the morning and seem ¡®glued¡¯ together. Viral infections may be more painful, with very red eyes and less discharge. They spread easily and can be passed on by contact and sharing towels, face flannels and so on. Allergic problems cause a gritty feeling, redness and watering of the eyes.

Treatment usually consists of frequently inserted eye-drops with, when there is a discharge, regular bathing with warm, salty water to get rid of the pus.

Sometimes more serious conditions can be mistaken for conjunctivitis. Medical attention should always be sought if:

• only one eye is affected;
• there is a lot of pain;
• vision is affected; or
• a small baby has discharging or red eyes.