Dry eyes are a common cause of eye irritation, estimated to affect 15% of adults over age 65. The tear film which covers the surface of the eye is made mostly of water, but also contains mucus, which helps the tear "stick" to the eye and an outer layer of lipid (oil) which slows evaporation of tears. The tear film lubricates the eye and smoothes irregularities for better vision. "Dry eye disease" is a name for several disorders of the tear film, which may be classified into two broad categories: (1) decreased tear production or (2) excessive tear evaporation. In both cases, water is lost from the tear film, leading to further deterioration of the health of the eye surface. Eventually, dry rough spots appear on the eye surface, which may reduce vision, and in severe cases, scarring may develop.

Causes of dry eye:

Dry eye becomes more common with increasing age and as body hormone changes occur. Most commonly affected are post-menopausal women. Rarely, there can be a genetic or hereditary cause of dry eyes. Several categories of medications taken by mouth may cause or worsen the symptoms dry eye, including:

• High blood pressure medications
• Decongestants
• Antidepressants
• Antihistamines

 

Treatments for dry eye:

	"Moisture Eyes" from Baush & Lomb

	"Bion Tears" from Alcon

Lubricating ointments are very useful, especially for nighttime use. Because these ointments blur the vision, they are less suitable for daytime use and are better for nighttime. Generally, only a small amount of ointment is necessary, about the size of a grain of rice. If the eyes are too blurry or sticky in the morning, it may be that too much ointment was used the night before.

In addition to using artificial tears, it is helpful to preserve the tears that are being produced. Wrap-around glasses can help seal in moisture particularly when they fit closely against the skin. Some opticians may be able to fit prescription glasses with side shields (moisture chambers) that help retain moisture. People with severe dry eyes may benefit from swim goggles, or moisture shields with a mild adhesive that adheres to the skin around the eyes.

As for most medical conditions, surgery is usually a last resort. Fortunately, there are some simple office procedures which can be extremely helpful for dry eyes. The most important one is known as "punctal occlusion". This is simply a way of sealing up the tear drainage so that one's tears are retained on the eye. This is similar to placing a plug in the drain in order to help a slow-running faucet fill the kitchen sink. There are several ways of doing punctal occlusion. These include "dissolving" plugs made from collagen, permanent plugs made from silicone, heat treatment or cautery, and even the laser. Your doctor can help you decide which treatment is most appropriate. The partial closure by sutures of the edges of the lids at the outer margin of the eye is another procedure which can be helpful for the patient with severe dry eye. This procedure reduces the amount of exposure and thus reduces evaporation of the tear film.

Current research has revealed much new information about what causes dry eye to develop. Hormonal factors are becoming understood, and will change how we treat dry eye. Within several years, hormone-containing tear substitutes may become available. Much work has been done on the use of medications which reduce inflammation on the eye surface. Regardless of the cause of dry eye, inflammation of both the eye surface and within the tear-producing gland is an important factor in further reducing the tear-producing functions of the gland. A newly approved medication eyedrop, Restasis, is now available which treats the cause of dry eye, rather than simply treating the symptoms. While this medication is not for everyone, it represents a major leap forward in our ability to treat dry eye.

Support groups, such as the Sjogren's Syndrome Foundation are especially helpful in bringing new research developments and practical information to the attention of people with dry eyes.

Helpful tips:

• Bottled artificial tears contain a preservative, and should not be used more than four to six times daily. If more frequent use is needed, unit-dose or non-preserved tears should be used. Several newer brands of bottled tears (Refresh tears, Genteal) have a rapidly disappearing preservative. These tears are better than preserved products, but not as safe as preservative-free tears.
• Thicker, higher viscosity tears provide longer lasting lubrication, but may blur for a time after their use.
• Bedtime lubricating ointments provide long lasting relief because they work during the time that tear production is lowest overnight.
• Moisture Tears PM and Hypotears ointments are lanolin-free. Rare patients are sensitive to lanolin and feel irritation from ointments which contain this ingredient.
• Use artificial tears on a set schedule, not after discomfort occurs. It is more effective to prevent symptoms than to relieve them.
• Avoid over-the-counter "eye whiteners" such as Visine, Clear Eyes, Albalon, Allergy drops, Degest 2, Murine Plus, Opcon, Naphcon, Prefrin, Relief, Soothe, etc.

The mainstay of treatment for dry eyes is artificial tears. Many good artificial tear preparations exist and are available in drugstores without a doctor's prescription. Some artificial tear preparations are thin and watery while others are thick and viscous. The thicker ones last longer but they may be somewhat sticky and have a tendency to blur the vision slightly. The ideal artificial tear is one that lasts a long time, is comfortable to put in the eyes, and does not cause blurring or stickiness. There is, however, no single ideal artificial tear preparation that is good for everyone. Often, people with dry eyes must try several different preparations to find the one that works best for them. In recent years, artificial tears without preservatives have become available in unit doses. These may have some advantages since people using artificial tears several times a day may react adversely to a preservative. Several brands include electrolytes (salts), which may help heal the damaging effects of dry or "concentrated" tears on the surface of the eye.

Low humidity environments, contact lens wear, wind, central heat or air conditioning and airplane travel are likely to cause worsening of dry eye symptoms. Certain autoimmune conditions, such as Rheumatoid arthritis and Lupus, occur together with dry eyes. The most severe form of dry eye is related to a condition known as Sjogrenýfs Syndrome. This condition affects several million people throughout the world. Not only are the eyes dry, but there is usually dryness of the mouth, nose, throat and other tissues throughout the body.

Dry eye disorders pose a challenging problem in diagnosis for physicians. Many different factors can contribute to dry eyes, and determining the cause may affect selection of the best treatment.