Dry Eye

If your eyes sting, itch or burn, you may be experiencing the common signs of "dry eye." A feeling of something foreign within the eye or general discomfort may also signal dry eye.

What is dry eye?

Dry eye describes eyes that do not produce enough tears. The natural tears that your eyes produce are composed of three layers:

• The outer oily layer, which prevents or slows evaporation of the tear film
• The middle watery layer; which moisturizes and nourishes the front surface of the eye
• The inner mucus layer, which helps maintain a stable tear film.

Dry eye may occur because the volume of tears produced is inadequate (we all produce fewer tears as we get older, and in some cases this can lead to dry eye symptoms). It may occur because the composition of the tears has changed so that they are unstable and evaporate more quickly.

What causes dry eye?

Dry eye symptoms can result from the normal aging process. Exposure to environmental conditions, as well as medications, such as antihistamines, oral contraceptives or anti-depressants, can contribute to the symptoms of dry eye. Dry eye can result from chemical or thermal burns to the eye. Dry eye may also be symptomatic of general health problems or other diseases. For example, people with arthritis are more prone to dry eye. In addition, you may have "dry-eye" like symptoms from allergies or even from a reaction to your contact lens solution.

How is it diagnosed?

During the examination, your eye care practitioner will ask about your general health, use of medications, and work and home environments to determine factors that may be contributing to dry eye symptoms. This information will help your doctor decide whether to perform dry eye tests. To test for dry eye, your doctor may use diagnostic instruments that allow a highly magnified view of your eyes or small strips of paper or thread and special dyes to assess the quantity and quality of the tears.

How is it treated?

Dry eye cannot be cured, but your eyes’ sensitivity can be lessened and measures taken so your eyes remain healthy. The most frequent method of treatment is the use of artificial tears or tear substitutes. For more severe dry eye, ointment can be used, especially at bedtime. To keep dry eye symptoms in check, you and your practitioner need to work together. Follow his or her instructions carefully. If you have increased dryness or redness that is not relieved by the prescribed treatment, let your practitioner know as soon as possible.

Will dry eye harm my eyes?

If untreated, it can. Excessive dry eye can damage tissue and possibly scar the cornea of your eye, impairing vision. Dry eye can make contact lens wear more difficult since tears may be inadequate to keep the lenses wet and lubricated. This can lead to irritation and a greater chance of eye infection. Therefore, it is important to follow your eye care practitioner’s recommended treatment plan.

What can you do about dry eye?

There is no known "cure" for dry eye. However, in most cases, dry eye can be treated with an artificial tear solution or, in more severe cases, by blocking the puncta. Whatever the treatment mode chosen, effective treatment of dry eye must either replace, enhance or retain natural tears.

To replace natural tears, an artificial tear solution can be effective. Artificial tears are available with and without preservatives. Preservative-free artificial tears are recommended for people who can’t tolerate preservatives or who must use these solutions many times per day.

If artificial tears are needed on more than an occasional basis, the type of preservative used is an important consideration. Many artificial tear solutions contain benzalkonium chloride (BAC), a preservative that with frequent use can actually damage the epithelium and lead to further problems.

To enhance natural tears, a more advanced artificial tear is required. Such solutions would include artificial tears with formulations containing zinc and bicarbonate, substances that can actually contribute to the growth and maintenance of healthy mucin, tear film, and epithelium. Often, overnight protection is needed. In these cases a more viscous preparation should be used, one that is designed to provide long-lasting protection and lubrication.

To retain natural tears, it is necessary to suppress the loss of tears by blocking the punctum (the natural drain for tears). This is done with the insertion of punctal plugs that actually block the opening of the punctum.

Plugs made for smooth insertion, comfortable wear and virtual invisibility are the most popular. In more severe cases, patients may need to be treated with eyelid inserts, tear duct plugs, protective glasses, bandage contact lenses or surgical procedures.