Some people do not produce enough tears to keep the eye comfortable. This is known as dry eye.

Tears are produced by two different methods. One method produces tears at a slow, steady rate and is responsible for normal eye lubrication. The other method produces large quantities of tears in response to eye irritation or emotions.

Tears that lubricate are constantly produced by a healthy eye. Excessive tears occur when the eye is irritated by a foreign body or when a person cries.

The usual symptoms of dry eye include:

• Stinging or burning eyes
• Scratchiness
• Stringy mucus in or around the eyes
• Eye irritation from smoke or wind
• Excess tearing
• Difficulty wearing contact lenses

Excess tearing from "dry eye" sounds illogical, but if the tears responsible for maintenance lubrication do not keep the eye wet enough, the eye becomes irritated. When the eye is irritated, the lacrimal gland produces a large volume of tears which overwhelms the tear drainage system. These excess tears then overflow from your eye.

How is dry eye treated?

Adding tears

Eye drops called artificial tears are similar to your own tears. They lubricate the eyes and help maintain moisture. Artificial tears are available without a prescription. There are many brands on the market, so you may want to try several to find the one you like best.

Preservative-free eye drops are available if you are sensative to the preservatives in artificial tears. If you need to use artificial tears more than every two hours, preservative-free brands may be better for you. Solid artificial tear inserts that are placed inside the lower lid on a daily basis and gradually release lubricants may be beneficial to some people.

You can use the tears as often as necessary, once or twice a day or as often as several times an hour.

Conserving the tears

Conserving your eyes' own tears is another approach to keeping the eye moist.

Tears drain out of the eye through a small channel into the nose (that is why your nose runs when you cry). Your ophthalmologist may close these channels either temporarily or permanently. The closure conserves your own tears and makes artificial tears last longer.

Other methods

Tears evaporate like any other liquid. You can take steps to prevent evaporation. In winter, when indoor heat is on, a humidifier or a pan of water on the radiator adds moisture to dry air. Wrap-around glasses may reduce the drying effect of the wind, but are illegal to wear while driving in some states.

Anything that may cause dryness, such as an overly warm room, hair dryers or wind, should be avoided by a person with dry eye. Smoking is especially bothersome.

Some people with dry eye complain of "scratchy eyes" when they wake up. This symptom can be treated by using an artificial tear ointment at bedtime. Use the smallest amount of ointment necessary for comfort, since the ointment can cause your vision to blur temporarily.

Dry eye due to a lack of vitamin A in the diet is rare in the United States but is more common in poorer countries, especially among children. Ointments containing vitamin A can help dry eye if it is caused by unusual conditions such as Stevens-Johnson syndrome or pemphigoid. Vitamin A supplements do not seem to help people with ordinary dry eye.

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