Dry Eye Syndrome

Cause

The cornea is the transparent anterior part of the eye, in front of the iris and the pupil. The conjunctiva is a thin layer of tissue that covers the white of the eye and the inside of the eyelids. In order to protect the cornea from dehydration, the lacrimal glands produce lacrimal fluid. By blinking, the eyelids distribute the lacrimal fluid over the eye.
Dry eye syndrome is caused by not properly functioning of the lacrimal gland and thus producing less lacrimal fluid. In case of dry eyes, tear production is in quantity or composition not sufficient to protect the eye. There may also be an increased evaporation of lacrimal fluid. Several underlying causes are possible:

• Allergy.
• Age.
• Physical conditions, such as the disease of Sjögren, hormonal defects.
• Medicines.
• Defects of the eyelids or conjunctiva.
• Little or poor blinking or sleeping with half-open eyes, e.g. in facial paralysis.
• Using contact lenses, often in combination with intensive computer work, increases the risk of dry eye symptoms.

Symptoms

In case of dry eyes, a person has the following signs and symptoms:

• Irritated eyes.
• A burning sensation in the eyes.
• Sometimes blurred vision.
• Constantly feeling like there is sand or dust in the eyes.
• The eyelids are stuck and covered with scabs, especially in the morning.

Particularly in a dry environment, a person may suffer from the eyes. Dry eye syndrome raises the risk of eye infections.

Diagnosis

In most cases, an ophthalmologist can identify the cause of dry eye syndrome and then provide the right treatment. The ophthalmologist can perform two tests by himself:

• Schirmer's test: measuring the amount of tears. This is done by anesthetizing the eyes and placing a paper strip in the eyes. After 5 minutes is measured how far the tears have run into the paper strip.
• Testing the quality of tears; this quality is also called the break-up time (BUT). With fluorescein, the rate of evaporation of the tear film is measured.

A patient can also be referred to another specialist, such as an internist or rheumatologist, for further investigation into the possible underlying cause.

Treatment

Dry eye syndrome may be treated as follows:

• Administration of artificial tears in the form of eye gel or eye drops.
• Obstruction of the drainage of tears. It's important to retain the remaining lacrimal fluid for as long as possible. This can be done by temporarily or permanently closing the tear drainage canal.

Prognosis

Dry eye syndrome is in many cases a chronic condition. This means that the symptoms often remain present to any extent and in varying severity.

Considerations

• Regular blinking is important to keep the eyes moist.
• Try not to rub, this can cause irritation.
• Clean the eyelids with a gauze with tap water. Wipe from the outside to the inside toward the nose.
• Make sure that the air inside your house is not too dry when the heater is turned on. For example, hang a bucket of water to the heater and fill the bucket regularly.
• Avoid rooms with air conditioning or airblowers. These devices produce a dry airflow, which extra irritates the eyes.

Facts

• The literal translation of ‘keratoconjunctivitis sicca’ is dryness of cornea and conjunctiva.
• The prevalence of dry eye syndrome is 10%.
• Women run a higher risk of having this condition than men.
• The probability of dry eye syndrome increases with age.