Dry eye syndrome is the general name for a group of conditions resulting in inadequate lubrication of the eye; either from insufficient tear production, poor quality tear film, or rapid drainage of the tears from the eye. The layer of tears that covers the surface of the eye is called the tear film, and is made up of three layers: a mucin layer, which ensures smooth coating over the surface of the cornea; an aqueous (watery) layer, which makes up the bulk of the tear volume; and a lipid (oily) layer that slows evaporation of the tears and creates a smooth exterior surface for clear vision.
There are a number of different causes of dry eye syndrome, and many patients with the condition have more than one contributing factor.
Inadequate tear production, keratoconjunctivitis sicca, is due to decreased function of the lacrimal gland, and can be associated with immune dysfunction, connective tissue disease, or thyroid disease. Hormone changes, especially those associated with pregnancy or menopause may result in dry eye. Poor quality tear film results in increased evaporation of the tears, and is often associated with blepharitis or meibomitis, inflammatory conditions of the eyelid and associated oil glands. Symptoms of dry eye may also arise if the eyelid is not properly positioned against the eye.
Dry eyes may feel gritty or sandy. Patients with dry eye syndrome may actually experience watery, teary eyes. This is because the poor quality of the tear film causes the cornea to send a signal to the lacrimal gland, resulting in production of the watery layer of the tear film. Patients may also experience a quick sharp stinging sensation, or burning. Some patients with severe dry eye have increased sensitivity to light.
Treatment of dry eye syndrome is dependent upon the underlying cause of the dry eye. The first line of treatment is the use of artificial tears to supplement the natural tear film. If there is blepharitis or meibomitis associated with your dry eye, your doctor may instruct you to use warm compresses and lid hygiene techniques. Prescription eye drops may be used in some cases of inadequate tear production to stimulate the lacrimal gland to produce more tears. In cases of excessive drainage of tears, punctal plugs are used to partially block this flow. Nutritional supplements may also be recommended.