What is Dry Eye?
Dry eye is an eye disease affecting the surface of the eye. This disease is chronic and progressive, getting worse over time. As it progresses, more damage can occur to the surface of the eye.
Dry eye can cause poor vision. Blurred vision while reading, computer use, watching TV, upon awakening or at the end of the day are all signs of a poor tear film. The tears form a clear film over the surface of the eye. When this tear film is deficient vision will be reduced. This is similar to water beading on the surface of your car after it is waxed. Without a smooth film over the surface of your eye, vision is reduced.
Symptoms
Dry eye can cause discomfort such as burning, stinging, itching, grittiness and a dry eye feeling. You may also feel like there is a foreign body in your eyes.
As odd as it may seem, dry eye patients may also experience excessive tearing. There are different types of tear glands including oil glands (meibomian glands) and watery glands (lacrimal glands). When the oil glands do not work well the watery glands produce more tears to try to wet the eye, but these watery tears do not work well if the oil glands are not functioning properly since these watery tears will evaporate quickly. In these cases, the eye will produce excessive watery tears to try to compensate for the lack of oil tears, but this does not solve the underlying dry eye problem as long as the oil tears are deficient.
There are two types of dry eye disease:
- Reduced oily tear production (MGD – meibomian gland dysfunction)
- Reduced watery tear production (Lacrimal Insufficiency)
Most dry eye disease (about 90%) is from reduced oily tear production due to dysfunction of the meibomian glands (oily tear glands) in the eyelids. When the meibomian glands become dysfunctional they produce less oily tears. These oily tears form a protective coating over the tear film which prevents the watery tears from evaporating. Less oily tears causes rapid tear film evaporation which causes dryness of the surface of the eye.
Causes
Dry eye is caused by many factors including age, hormone changes, autoimmune disease (Sjogren’s syndrome), rosacea, some medications and extended computer use or reading. Contact lens wear can affect dry eye. Dry eye affects women more than men. Dry eye is very prevalent and affects millions of people.
