Some people do not produce enough tears to keep the front surface of the eye lubricated and comfortable. This condition is known as dry eye.
What is going on in the body?
Tears are secreted by nearby glands and have several purposes. They act to keep the front surface of the eye lubricated and moist. They also keep the surface smooth so that light enters the eye through a suitable surface for clear vision. The tears also contain antibacterial substances that protect against infection. Without enough tears, irritation or even damage to the front of the eye may occur.
What are the causes and risks of the condition?
The risk of dry eye increases with age. This is because tear production normally decreases with age. Dry eye is also more common in women, especially after menopause.
Dry eye can be caused by:
autoimmune diseases. These are disorders in which a person's immune system attacks his or her body for no apparent reason. For example, in a condition called Sjogren syndrome, people get dry eyes, a dry mouth, and arthritis.
medications such as diuretics or "water pills." Antihistamines, such as diphenhydramine, sleeping pills, medications for nerves, and pain relievers can also cause dry eye.
neurologic disorders, such as Lou Gherig's disease, also called amyotrophic lateral sclerosis. In these conditions, the nerves that cause the glands to secrete tears are not working.
damage or scarring of the front of the eye or the glands that make tears.
eyelid problems, such as lids that cannot close properly.
cancers, such as blood cancer, although this is rare.
the environment. For example, when the humidity is very low, people may notice their eyes feel dry.
Other causes are also possible. In some cases, the cause for dry eye cannot be found.