What is dry eye?
Normally your eyes are kept moist by the tears that bathe the surface. The action of blinking spreads the tears across the surface of your eyes. Tears contain important substances that lubricate the eyes, prevent infection and slow down evaporation of the tears.
Dry eye is one of the most common of all eye conditions. Although it particularly affects older people, it can occur at any age. It is also more common in women.
Dry eye can occur for several reasons – either because you do not make enough tears or because your tears evaporate too quickly.
What are the symptoms of dry eye?
Stinging, burning or a gritty feeling in your eyes are common symptoms. Your eyes may look red, feel heavy and become sensitive to bright light. Stringy mucus may collect on the lids. Symptoms may be worst when you first wake up, but improve as the day goes on, or vice versa.
Symptoms can be triggered by various situations. These include:
- Activities that make you blink less often, eg reading, driving, working at a computer monitor or watching television.
- Exposure to fumes, dust and cigarette smoke can be particularly aggravating.
- Air-conditioning which can produce a dry atmosphere.
- Fortunately dry eye is unlikely to affect your sight. However, if your eyes are very dry the symptoms may be intolerable.
What causes dry eye?
The most common cause of dry eye is a failure of the glands in your eyelids to produce tears, which often occurs as part of the ageing process. Blockage of the oil glands in the eyelids may worsen the problem.
Medicines used in the treatment of medical conditions, such as high blood pressure or kidney disease, can reduce the production of tears.
Less often, dry eye may be part of a medical condition, such as Sj