Dry Eye, as the name implies, is a condition in which the eyes do not produce enough moisture in the form of tears to keep eyes comfortable. Dry eye is a chronic condition that affects the three–layered tear film that covers the eyes. Both eyes are usually affected.
Symptoms usually include a stinging or burning sensation, scratchiness, blurry vision, irritation from smoke or wind, sensitivity to light, stringy mucus in or around the eye, difficulty wearing contact lenses, eye fatigue after short periods of reading, and others.
Oddly, excess tearing can also be a symptom. If the tears responsible for maintenance lubrication do not keep the eye wet enough, the eye becomes irritated. The lacrimal gland produces a large volume of tears which overwhelms the tear drainage system. These excess tears then overflow from the eye.
Because tear production tends to diminish with age, dry eye mostly affects older people. Also, dry eye is more common in women, especially after menopause. Dry eye can also be associated with other medical conditions such as diabetes, rheumatoid arthritis, lupus, and others, as well as use of certain medications.
Most people with dry eyes do not experience long–term complications. Treatment, determined by your ophthalmologist, is usually in the form of medications and self care.
The production of tears is an essential eye function. Not only do tears keep the surface of the eye (the cornea) naturally lubricated, but also help to protect the eyes from infection. The tear film coating that covers the eye is made of three layers
The lipid layer is the outer–most layer and contains fatty oils produced by small glands (meibomian glands) on the edge of the eyelids. This layer slows down the evaporation of the middle aqueous (watery) layer. Clogged meibomian glands can contribute to dry eye problems.
The aqueous layer is the middle layer and is mostly water and a little bit of salt. This layer, which is produced by the tear glands, cleans the eyes and washes away particles and irritants.
The mucous layer is the inner–most layer and allows the tears to spread evenly across the surface of the eye’s cornea.