A new drug named Restasis means that dry eye -- a common problem in older people -- can now be treated more effectively.
An estimated 10 to 14 million people in the United States suffer from dry eye syndrome. Dry eye is a condition characterized by a decline in the quantity and/or quality of the tears that normally bathe the eyes and wash away foreign particles. A 2003 study in the American Journal of Ophthalmology involving almost 40,000 women estimated that about 8% of American women over age 50—more than 3.2 million people—are affected by dry eye. Men also develop dry eye, and the incidence of dry eye increases with age.
Treatment for dry eye is important to relieve discomfort and prevent scarring, which can lead to vision loss. Until recently, there were only two options for mild to moderate symptoms of dry eye: artificial tears (available as over-the-counter eye drops) or a change in systemic medications (since dry eye is a side effect of many drugs). Both approaches are often unsatisfactory, however.
Today there is another option for dry eye—a topical form of Restasis (cyclosporine)—that addresses inflammation, now thought to be a major underlying cause of dry eye. “Most patients with dry eyes should consider Restasis, and they should be treated early to prevent scarring and possible loss of vision,” says Esen Akpek, M.D., Associate Professor of Ophthalmology at Johns Hopkins who leads the Ocular Surface and Dry Eye Clinic at the Wilmer Eye Institute.
Causes of Dry Eye
The protective film of tears that spreads over the surface of the eyes is a complex fluid consisting of three layers: an inner layer of mucus produced by the conjunctiva (the membrane covering the surface of the eyeball); a watery middle layer, made by the lacrimal glands located above the outer corner of each eye; and an oily outer layer, produced by the meibomian glands that lie behind the upper and lower eyelashes. Symptoms of dry eye develop when the body no longer adequately produces and maintains tears. Research has identified three major factors that contribute to dry eye syndrome:
- Aqueous tear deficiency, insufficient fluid in the middle layer of tear film. Inflammation appears to play a key role in dry eye syndrome because dry eyes frequently occur with autoimmune diseases, such as Sjogren’s disease, rheumatoid arthritis, and systemic lupus erythematosus, which are characterized by inflammation.
- Evaporative loss, a deficiency in the outer oily layer that normally prevents evaporation of the tears. A decline in testosterone (an androgen, or male hormone) appears to promote evaporation. Both the lacrimal and the meibomian glands have receptors that respond to testosterone. As people age, their testosterone levels decline. This drop is especially marked in postmenopausal women because the baseline testosterone level in women is already low. Testosterone deficiency can lead to decreased production of the watery portion of tears as well as loss of the oily layer, leading to evaporative loss.
- Certain medications. Many medications, including diuretics, antihistamines, and antidepressants, can cause dry eyes by interfering with the body’s ability to produce tears.
Regardless of the cause, dry eye symptoms include stinging or burning eyes, scratchiness, stringy mucus in or around the eyes, excessive eye irritation from smoke or wind, excessive tearing, difficulty wearing contact lenses, and, occasionally, blurred vision caused by the uneven corneal surface.
In addition, environmental factors, such as low humidity or drafts, can make symptoms of dry eye worse.
Treatment Options for Dry Eye
If you take a medication associated with dry eyes, your doctor may be able to substitute another drug or decrease the dosage.
Lifestyle measures, such as using a humidifier or shielding the eyes from drafts, may also help relieve dry eye, as can the use of artificial tears. But most people with dry eye require additional measures.
“Artificial tears can ease symptoms, but meanwhile, there will still be smoldering inflammation on the eye surface that can eventually lead to scar formation on the tear-secreting glands,” notes Dr. Akpek. In addition, artificial tears can be inconvenient because they require frequent application.
Topical cyclosporine, on the other hand, counters inflammation, decreases the need for artificial tears, and appears to have few, if any, side effects.
Several other approaches to dry eye show promise. They include a higher intake of omega-3 fatty acids (found in fish); topical androgen eye drops; and diquafosol, a medication that increases the volume of ocular fluid. Clinical trials are also under way for several anti-inflammatory drugs.
When To Consider Surgery for Dry Eye
When other treatments fail and additional relief for dry eye is needed, or symptoms are severe and threaten vision, surgical closure of the tear ducts (punctal occlusion) may be an option. The procedure involves closing one of the channels in the eyelid through which tears drain from the eyes into the nose. The channels may be closed permanently with silicone plugs or temporarily with plugs made of collagen.
“Punctal occlusion will keep the eye surface nice and moist, but if there is significant inflammation, certain inflammatory substances in tears will remain on the eye surface for longer than normal, and that may be harmful,” Dr. Akpek says. “So I don’t do punctal occlusion by itself. I combine it with cyclosporine therapy to reduce inflammation.”
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Posted in Vision on April 17, 2006
Reviewed May 2007
