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dryeye

dryeye

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Overview

Dry eye syndrome is one of the most common problems treated by eye physicians. Over ten million Americans suffer from dry eyes. It is usually caused by a problem with the quality of the tear film that lubricates the eyes.

Tears are comprised of three layers. The mucus layer coats the cornea, the eye's clear outer window, forming a foundation so the tear film can adhere to the eye. The middle aqueous layer provides moisture and supplies oxygen and other important nutrients to the cornea. This layer is made of 98 percent water along with small amounts of salt, proteins and other compounds. The outer lipid layer is an oily film that seals the tear film on the eye and helps to prevent evaporation.

Tears are formed in several glands around the eye. The water layer is produced in the lacrimal gland , located under the upper eyelid. Several smaller glands in the lids make the oil and mucus layers. With each blink, the eyelids spread the tears over the eye. Excess tears flow into two tiny drainage ducts in the corner of the eye by the nose. These ducts lead to tiny canals that connect to the nasal passage. The connection between the tear ducts and the nasal passage is the reason that crying causes a runny nose.

In addition to lubricating the eye, tears are also produced as a reflex response to outside stimulus such as an injury or emotion. However, reflex tears do little to soothe a dry eye, which is why someone with watery eyes may still complain of irritation.

Dry eye syndrome has many causes. One of the most common reasons for dryness is simply the normal aging process. As we grow older, our bodies produce less oil ? 60% less at age 65 then at age 18. This is more pronounced in women, who tend to have drier skin then men. The oil deficiency also affects the tear film. Without as much oil to seal the watery layer, the tear film evaporates much faster, leaving dry areas on the cornea.

Many other factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people also find their eyes become irritated when reading or working on a computer. Stopping periodically to rest and blink keeps the eyes more comfortable.

Contact lens wearers may also suffer from dryness because the contacts absorb the tear film, causing proteins to form on the surface of the lens. Certain medications, thyroid conditions, vitamin A deficiency, and diseases such as Parkinson's and Sjogren's can also cause dryness. Women frequently experience problems with dry eyes as they enter menopause because of hormonal changes.

Symptoms

  • Itching
  • Burning
  • Irritation
  • Redness
  • Blurred vision that improves with blinking
  • Excessive tearing
  • Increased discomfort after periods of reading, watching TV, or working on a computer

Treatment

Tear Therapy

Once your procedure is completed, you will be able to go home almost immediately. You will be asked to take an antibiotic and steroid eye drops for the next 5-7 days. There are certain activity restrictions after the procedure:

Artificial tears remain the primary treatment for mild to moderate keratoconjunctivitis sicca (KCS). Most artificial tears are derivatives of cellulose or polyvinyl alcohol; several newer preparations mimic the action of mucous.)

All of the preparations in these categories contain preservatives (chlorbutanol, benzalkonium chloride, or thimerosal), and all must be instilled regularly and frequently to compensate for inadequate tear volume or an unstable tear film. A number of tear preparations of each type are available; however, all such preparations have the same drawback: insufficient duration. The patient usually selects the most suitable and least irritating artificial tear by trial and error. One of the big advancements in tear therapy has been the introduction of preservative free preparations. Usually these products are packaged in single dose dispensers that can be used and discarded at the end of the day. Although less convenient than tears in larger bottles, they are appropriate for individuals requiring very frequent instillation of tears (hourly or more frequent) or for patients sensitive to a given preservative.

Ointments offer the advantage of increased viscosity and retention time, however, they have not been found to be uniformly superior to conventional tears, and at times, they may blur vision because of their increased viscosity. They are particularly helpful for use at bedtime or in individuals with more severe disease.

Punctal Occlusion

Conserving existing tears by reversible (punctal plugs) or irreversible (punctal cautery) punctal occlusion can be of tremendous benefit to KCS patients with severely deficient aqueous tear volume. Punctal occlusion prolongs the action of artificial as well as natural tears by retaining them longer in the conjunctival cul-de-sac. One method of occlusion is to place a silicone based punctal plug into the tear drainage holes of the lids. The advantage of this type of punctal occlusion is its reversibility. If punctal plugs appear to relieve the symptoms of KCS with few or no problems, then permanent punctal occlusion via cautery may be considered.

Tarsorrhaphy

In severe cases of dry eye it is appropriate to consider partial or total surgical closure of the eyelids. This is known as a tarsorrhaphy. This procedure decreases the surface area that the eye needs to keep lubricated.