Tears are usually associated with crying, often as a result of unhappiness or pain. But our eyes are continuously making tears. They are important for protection, lubrication and cleaning.

Tears are secreted by tiny glands (lacrimal glands) situated above the outer corner of each eye.

They flow across the eye, acting as a sort of lubricant. Their spread is helped by blinking.

Tears leave the eye by draining into 2 tiny canals, the lacrimal ducts (sometimes called tear ducts), situated near the corner of each eye next to the nose. The lacrimal ducts join together forming the nasolacrimal duct, down which tears flow into the nose.

When things go wrong with this system one of 2 things may happen. There may be a watery eye or a dry eye.

Watery eyes are sometimes due to excessive production of tears. This can happen as a result of wind and glare, or some allergic stimulus. But usually watery eyes are due to a problem, usually a blockage, in the drainage system. Blockage of the lacrimal ducts is common, especially in tiny babies. This may lead to recurring infections (conjunctivitis) of the eye's surface layer.

In children, regular massaging of the area between the eye and nose may unblock the tear ducts. Sometimes they need probing or syringing to be cleared. Very rarely an operation is needed to allow tears to drain into the nose.

Dry eyes are common with increasing age, when tear production is reduced. Certain diseases, such as rheumatoid arthritis, and certain drugs such as diuretics (¡®fluid tablets¡¯) are associated with dry eyes.

People with dry eyes usually notice an uncomfortable ¡®gritty¡¯ feeling in the eye. This can be relieved by frequent use of drops, or ¡®artificial tears¡¯, which can be used as often as necessary. Sometimes ointment inserted at night, when tear production is lowest, helps.