Tears serve to lubricate the eye and they are produced around the clock, but when insufficient moisture is produced stinging, burning, scratchiness and other symptoms are experienced and may be referred to as Dry Eye, Keratitis Sicca, Keratoconjunctivitus Sicca (KCS) or Xerophthalmia.
When we blink, tears form a film, which spreads over the eye, making the surface smooth and optically clear and enabling good vision. There are three layers in the thin film of tears: an oily layer, a watery layer and a layer of mucus, each with specific function.
The outermost, oily layer is produced by small glands at the edge of the eyelid (meibomian glands) and the main purpose of this layer is to smooth the tear surface and reduce evaporation.
The middle, watery layer, is produced by small glands through the conjunctiva, (the delicate membrane lining the inside of the eyelid) and by the large lacrimal (tear) gland. This layer cleanses the eye and washes away foreign particles of irritants. The innermost layer consists of mucus which allows the water layer to spread evenly over the surface of the eye. Without mucus, tears would not adhere to the eyelid
What causes Dry Eye?
Dry eye is caused when the tear gland produces insufficient tears. This can happen as part of the normal ageing process. It is more common among women, so although the condition is not common it tends to occur with increasing age when it is not always noticed because the effect of dry eye tends to balance another age-related change: poor tear drainage. The result of this is an imbalance caused by a reduction in lacrimal fluid.
People with Sjogren’s syndrome are at risk of dry eye as part of a more systemic problem involving salivary glands and other sites of mucus membrane. Salivary gland involvement produces a dry mouth as well. This syndrome, and dry eyes generally, may be found in people with rheumatoid arthritis.
What are the effects of the condition?
People with dry eye rarely have a sensation that the eye is dry but instead experience irritation, burning, a sensation of having a foreign body in the eye, mucus discharge and possible temporary blurring of vision. Blinking may cause pain to people with severe forms of keratitis
Is there any treatment for Dry Eye?
The aim of treatment will be to relieve discomfort and prevent corneal damage. In some situations relief may be found by blinking consciously when doing close or continuous work. It is also helpful to close the eyes for a spell from time to time.
Eye drops may be prescribed or purchased over the counter and since there is a variety, it may be helpful to try others if your present product does not suit you. Some drops contain preservative, which means they are safe to use for a month after opening, but although these drops are cheap are cheap and suitable for most sufferers, some people do not tolerate the preservative and may need to get prescription from the hospital pharmacy for a preservative free medication.
Lubricant ointments are also helpful, particularly at night. These are also available without preservative. Some women benefit from hormone replacement therapy (HRT), especially those whose dry eye problems began around or after the menopause.
Antihistamines or certain types of travel sickness pills inhibit tear secretion and symptoms can vary from day to day and be affected by general health. Surgical procedures may be indicated if symptoms are severe despite drops.
It involves closing the tear drainage holes in the eyelids permanently. It is a minor operation, which is suitable for some patients.
Is there anything that can help?
Avoiding the following situations will minimise your risk of Dry Eye
1. Reduce the dry eye atmosphere caused by central heating by using a humidifier.
2. Avoid car heaters, particularly at face level.
3. Sit away from direct heat such as gas or electric fires.
4. Use eye drops just before activities, which cause additional pain or discomfort such as television, reading, sewing and writing.
5. Remember to blink regularly, particularly when doing close or concentrated work.
6. Blink properly with full lid closure, not ‘half’ blinking.
7. Avoid smoky atmospheres.
Will the condition improve?
Prognosis varies considerably and may depend in art upon individual lifestyle choices and overall health as well as the severity and cause of the condition. There is no definite cure, but people can usually be made more comfortable.