The eye depends on the flow of tears to provide constant moisture and lubrication to maintain vision and comfort. Tears are a combination of water, for moisture; oils, for lubrication; mucus, for even spreading; and antibodies and special proteins, for resistance to infection. These components are secreted by special glands located around the eye. When there is an imbalance in this tear system, a person may experience dry eyes.
When tears do not adequately lubricate the eye, a person may experience:
Sometimes, a person with a dry eye will have excess tears running down the cheeks, which may seem confusing. This happens when the eye isn't getting enough lubrication. The eye sends a distress signal through the nervous system for more lubrication. In response, the eye is flooded with tears to try to compensate for the underlying dryness. However, these tears are mostly water and do not have the lubricating qualities or the rich composition of normal tears. They will wash debris away, but they will not coat the eye surface properly.
What Causes Dry Eyes?
In addition to an imbalance in the tear-flow system of the eye, dry eyes can be caused by situations that dry out the tear film. This can be due to dry air from air conditioning, heat, or other environmental conditions. Other conditions that may cause dry eyes are:
How Are Dry Eyes Treated?
Though dry eyes cannot be cured, there are a number of steps that can be taken to treat them. You should discuss treatment options with an eye care specialist. Treatments for dry eyes may include:
Artificial tear drops and ointments. The use of artificial teardrops is the primary treatment for dry eye. Artificial teardrops are available over the counter. No one drop works for everyone, so you might have to experiment to find the drop that works for you. If you have chronic dry eye, it is important to use the drops even when your eyes feel fine, to keep them lubricated. If your eyes dry out while you sleep, you can use a thicker lubricant, such as an ointment, at night.
Temporary punctal occlusion. Sometimes it is necessary to close the ducts that drain tears out of the eye. This may be done temporarily with a dissolving plug that is inserted into the tear drain of the lower eyelid to determine whether permanent plugs can provide an adequate supply of tears.
Non-dissolving punctal plugs and punctal occlusion by cautery (application of heat to tear exit duct). If temporary plugging of the tear drains works well, then longer-lasting plugs or cautery may be used. These measures increase the tear level by blocking the “drainpipe” through which tears normally exit the eye and enter the nose. The plugs can be easily removed. Rarely, the plugs may come out spontaneously or migrate down the tear drain. Many patients with particularly bothersome dry eyes find that the plugs or surgical occlusion (cautery) improve comfort and reduce the need for artificial tears.
Lipiflow is a medical device that uses heat and pressure on the eyelids to unclog blocked glands. These glands produce oil as part of the tear film. The oil lubricates the eye and prevents the tears from evaporating.
Restasis. The FDA approved the prescription eye drop Restasis for the treatment of chronic dry eye. It is currently the only prescription eye drop that helps your eyes increase their own tear production with continued use.
Other medications and nutrition. Other medications, including steroid eyedrops, can be used for short periods of time as an adjunct to other long-term measures. There is growing evidence that increasing the oral intake of fish oil and omega-3 via diet or supplement is very helpful to those suffering with dry eye.