Dry eye is a condition where tear fluid is not produced enough, the quality of tear fluid has changed or tear fluid is evaporated to an exceptional extent.
If tear fluid is not produced enough, the underlying reason is normally a dysfunction of the lacrimal gland (gland which produces tears) while too strong evaporation of tear fluid may have various causes, such as the diseases of lacrimal glands and eyelids. Symptoms of dry eye are more frequent in females and elderly people. It is estimated that more than 15% of people 55 years or older have some kind of dry eye syndrome.
Symptoms
The most common symptoms of dry eye are redness, stinging, foreign body sensation and itching in the eyes. The eyes may also be sensitive to light or feel tired, even painful. Sometimes there may be tearing, reflexive production of tears when the eye becomes irritated. In this case the tear fluid contains too much water and does not work as healthy tear fluid. Also blurring of vision is possible, because the optic surface formed by the tear film (a film that reflects light, protects, moisturizes, lubricates and nourishes the eye) is broken.
Causes
Dry eye has various causes, such as:
age-related changes in production and composition of tear fluid
certain systemic diseases, such as Sjogren's syndrome, vitamin A deficiency
certain medicines to treat high blood pressure, anti-anxiety and anti-psychotic drugs, birth-control pills, diuretics and allergy medicines
environmental conditions, such as dry indoor air, air-conditioning, dust, electric work environment, wind, frost, hot sun
working at a computer monitor, when dry eye is often caused by reduced or insufficient blinking
wearing contact lenses
corneal refractive surgery (PRK, LASIK)
Diagnosis
The patient usually comes to see a doctor because they have some symptoms. In examination, redness can be usually observed in both eyes. The doctor may color the surface of the eye with a dye when, in clear cases, a typical coloring on the cornea can be observed. The Schirmer test (a paper slip is put on the inside of the lower eyelids, which is wetted with tear fluid) is used to measure the tear production of the eye. If the result clearly deviates from the reference, the tear production is disturbed.
Treatment
There is no cure for the disease. However, the symptoms can be alleviated. If dry eye becomes severe it may lead to ulcers of the surface of the eye, which may be difficult to treat. Such problems are rather rare. If a specific condition causing dry eye, such as a structural defect of eyelids or chronic inflammation of eyelids, is successfully treated, dry eye symptoms are naturally diminished. Dry eyes are treated almost solely with tear substitutes, which lubricate the surface of the eye. Dry eye products are often applied several times per day. If the use is chronic and/or the product is applied several times a day, or if you wear contact lenses or are sensitive to the preservative used in eye drops, you should use preservative-free products.
