What is Dry Eye Syndrome?
Dry Eye Syndrome (DES) is a disease which can cause a variety of signs and symptoms affecting the vision and/or the comfort of the eyes.
A normal, healthy eye has a protective tear film. When you blink, a film of tears spreads over the eye, making the surface of the eye smooth and clear. Without this tear film, good vision would not be possible. The tear film is made of three layers:
- The oily layer (outermost) is secreted by the meibomian glands; its main purpose is to reduce the evaporation of tears.
- The mucous layer (innermost) is produced by conjunctival goblet cells; its purpose is to keep tears on the cornea.
- The watery layer (middle) is produced by the lacrimal gland. This layer functions to wash away foreign particles.
These layers work together to constantly bathe the eye in tears. By producing tears at a slow and steady rate, the eye stays moist and comfortable. DES occurs when there is a decrease in the quantity and/or quality of the tear film. This condition is associated with an increased tear film osmolarity, inducing inflammation.
What Are the Symptoms?
- Dryness or grittiness
- Foreign body sensation
- Burning or stinging
- Sensitivity to light
- Excessive tearing
- Blurred vision and/or fluctuating vision
- Stringy mucus in or around the eyes
It may sound illogical that excess tearing can occur with “dry eye,” but it can be understood as the eye’s response to discomfort. If the tears responsible for maintaining lubrication do not keep the eye wet enough, the eye becomes irritated. Eye irritation prompts the gland that makes tears (the lacrimal gland) to release a large volume of tears, overwhelming the tear drainage system. These excess tears then overflow from your eye.
What Causes Dry Eyes?
Tear production normally decreases as we age. Although dry eye can occur in both men and women at any age, women are most often affected. This is especially true after menopause.
A wide variety of common medications – both prescription and over-the-counter – can cause dry eye by reducing tear secretion. Be sure to tell your eye doctor the names of all of the medications you are taking, especially if you are using: diuretics, beta-blockers, antihistamines, sleeping pills, medications for “nerves” or pain relievers. Since these medications are often necessary, DES may be treated with eye drops called artificial tears.
People with DES are often more prone to the toxic side effects of eye medications, including artificial tears. For example, the preservatives in certain eye drops and artificial tear preparations can irritate the eye. These people may need special preservative-free artificial tears.
What Are the Risk Factors?
- Aging (40+)
- Recent eye surgery
- Certain medication use
- Eyelid problems
- Autoimmune disease
- External (computer use, contact lenses)
Your eye doctor can diagnose DES during your eye examination. Common dry eye tests incorporate dye solutions that highlight dry spots and/or paper strips or threads placed on the eyelids to measure the rate of tear production.
Treatment varies because the severity of the disease varies. Mild DES may be properly managed with basic eyelid hygiene and use of an over-the-counter (OTC) artificial tear. There are many OTC tears, both preserved and preservative free, and of various consistencies; ask your doctor which will work best for you. You can use the artificial tears as often as necessary – once or twice a day or as often as several times an hour. If you are using artificial tears more than 3-4 times a day with no relief, or find instillation or affordability to be a concern, you may want to consider the use of punctual plugs. Moderate to severe DES usually needs more attention. There are antibiotic and/or steroidal/non-steroidal anti-inflammatory medications that may be prescribed.
Restasis® is a prescription medication that is very successful in the management of DES. This medication not only lubricates the eye, but it induces the lacrimal gland to make more tears. Ask your doctor if Restasis® may help you.
Another successful approach to DES is conserving the body’s own tears through the use of punctal plugs (See figure to the right). Normally the tears drain out of the eye through a canal into the nose. Your eye doctor can plug these holes with temporary or long-term plugs to keep the tears on the eye longer, thus keeping the eyes more moist. The procedure is non-invasive and can be done quickly and easily during the eye exam. Ask your doctor if you are a good candidate for punctal plugs.