Dry Eye

Definition

Dry eye occurs when there is insufficient lubrication in the eye, and the conjunctiva becomes much less moist than normal. This causes pain and discomfort in the eyes. It may occur as a result of the following:

• Any condition that causes corneal scarring, such as erythema multiforme, trachoma, or corneal burns

• Sjogren's syndrome

• Lagophthalmos

• Riley-Day syndrome

• Absence of lacrimal gland

• Paralysis of the facial or trigeminal nerves

• Medication with atropine

• Deep anesthesia

• Debilitating diseases

Description

There are two kinds of tears: those that lubricate the eye; and those that are produced in response to irritation or emotion. Excessive tears occur when a foreign body irritates the eye or when a person cries.

Tears that lubricate the eye are produced around the clock, and they have an important everyday function. A film of tears, spread over the eye by a blink, makes the surface of the eye smooth and optically clear. Without the tear film, good vision would not be possible.

The tear film consists of three layers: an outer oily layer, a watery layer, and a layer of mucus.

Some people do not produce enough lubricating tears to keep the eye wet and comfortable. Tear production normally decreases with age, or it can be due to a disease or medication.

Dry eyes can make it difficult or impossible to wear contact lenses.

Causes and Risk Factors

Although dry eyes can occur in both men and women at any age, women are most often afflicted, especially after menopause,.

Dry eyes can also be associated with arthritis and accompanied by a dry mouth. People with dry eyes, dry mouth, and arthritis have Sjogren's syndrome.

Drugs and medications can also cause dry eyes by reducing tear secretion. Since these medications are often necessary, the dry eye condition may have to be tolerated or treated with "artificial tears."

Symptoms

Stinging, burning, scratchiness, stringy mucus, and excess irritation from smoke are the usual symptoms.

Surprisingly, increased tearing may be a symptom of dry eyes. If the basic tear secretion is below normal, excess tears are produced by the lacrimal gland in response to irritation. Even though the eye is basically dry, overflow tearing can occur, masking the dryness that caused the tears in the first place.

Treatment

Replacing natural tears with artificial tears is the basis of treatment. Artificial tears are available without prescription and are used as eyedrops to lubricate the eyes and replace the missing moisture. There are many brands of artificial tears on the market, and many people try several different brands to find one that suits them best.

The tears may be used as often as necessary - only once or twice a day, or as often as several times an hour. Solid inserts that gradually release lubricants during the day are also beneficial to some people.

Conserving the naturally produced tears is another approach to keeping the eyes moist. After bathing the eye's surface, tears enter a small opening in each lid, the punctum, and drain through a small canal, the canaliculus, into the lacrimal sac and down the naso-lacrimal duct into the nose. These channels may be closed temporarily, or permanently, by your ophthalmologist. The closure creates a reservoir of tears which allows the eyes to stay moist for longer periods of time.

Other methods of coping include using a humidifier in winter, and avoiding anything that adds dryness to the air, such an overly warm room, hair dryers, or being outside on windy days. Anything that adds an irritant to the air will also make a person with dry eyes more uncomfortable. Smoking is especially bothersome.

Some people complain of "scratchy eyes" upon awakening. Using an ointment at bedtime can treat this symptom. Use the smallest amount of ointment necessary for comfort, since the ointment can cause temporary blurring of vision.

Although ointments containing vitamin A seem to be of benefit to people with severe dry eye due to scarring from Stevens-Johnson syndrome or pemphigoid, vitamin A does not seem to help people with ordinary dry eye.

Questions to Ask Your Doctor

What is causing the below-normal tear secretion?

Is it a result of some other medical condition?

Is it related to any medications that I currently take?

What can be done to lubricate the eyes?

Do you recommend use of artificial tears?

Which brand of artificial tears should I use?

Do you have any specific suggestions for maintaining a moist environment?

Can the condition be cured?