Dry eye syndrome is a chronic lack of sufficient lubrication and moisture in the eye. Its consequences range from subtle but constant irritation to ocular inflammation of the anterior (front) tissues of the eye.

Dry Eye Syndrome Symptoms and Signs

Persistent dryness, scratching and burning in your eyes are signs of dry eye syndrome. These symptoms alone may be enough for your eye doctor to diagnose dry eye syndrome. Sometimes he or she may want to measure the amount of tears in your eyes. A thin strip of filter paper placed at the edge of the eye, called a Schirmer test, is one way of measuring this.

Some people also experience a "foreign body sensation," the feeling like there's something in the eye. And, it may seem odd, but sometimes watery eyes can result from dry eye syndrome, because the excessive dryness works to overstimulate the watery component of your eye's tears.

What Causes Dry Eyes?

Tears bathe the eye, washing out dust and debris and keeping the eye moist. They also contain enzymes that neutralize the microorganisms that colonize the eye. Tears are essential for good eye health.

In dry eye syndrome, the eye doesn't produce enough tears, or the tears have a chemical composition that causes them to evaporate too quickly.

Dry eye syndrome has several causes. It occurs as a part of the natural aging process, especially during menopause; as a side effect of many medications, such as antihistamines, antidepressants, certain blood pressure medicines, Parkinson's medications, and birth control pills; or because you live in a dry, dusty or windy climate. If your home or office has air conditioning or a dry heating system, that too can dry out your eyes. Another cause is insufficient blinking, such as when you're staring at a computer screen all day.

Dry eyes are also a symptom of systemic diseases such as lupus, rheumatoid arthritis, rosacea or Sjogren's syndrome (a triad of dry eyes, dry mouth, and rheumatoid arthritis or lupus).

Long-term contact lens wear is another cause; in fact, dry eyes are the most common complaint among contact lens wearers. Recent research indicates that contact lens wear and dry eyes can be a vicious cycle. Dry eye syndrome makes contact lenses feel uncomfortable, and the rubbing of the lenses against the conjunctiva seems to be a cause of dry eyes.

Incomplete closure of the eyelids, eyelid disease and a deficiency of the tear-producing glands are other causes. Tears are composed of three layers: the outer, oily, lipid layer; the middle, watery, lacrimal layer; and the inner, mucous or mucin layer. Each layer is produced by a different part of the eye (the lacrimal gland produces the lacrimal layer, for example), so a problem with any of those sources can result in dry eyes.

Dry eye syndrome is more common in women, possibly due to hormone fluctuations. Recent research suggests that smoking and taking multivitamins can increase your risk of dry eye syndrome, and that eating a lot of omega-3 fatty acids (found in cold-water fish) may decrease your risk.

Treatment for Dry Eyes

Dry eye syndrome is an ongoing condition that may not be cured (depends on the cause), but the accompanying dryness, scratching and burning can be managed. Your eye care practitioner may prescribe artificial tears, which are lubricating eye drops that may alleviate the dry, scratching feeling.

Restasis eye drops (cyclosporine in a castor oil base) go one step further: they help your eyes to increase tear production. Restasis treatment is the first of its kind.

If the problem is environmental, you should always wear sunglasses when outdoors, to reduce exposure to sun, wind, and dust. Indoors, an air cleaner can filter out dust and other particles from the air, while a humidifier adds moisture to air that's too dry because of air conditioning or heating.

Temporary or permanent silicone plugs in the lacrimal (tear) ducts keep tears in your eye from draining away as quickly. Called lacrimal plugs or punctal plugs, they can be inserted painlessly while you're in the eye doctor's office and are normally not felt once inserted.

A new type of punctal plug made of acrylic is a small rod that becomes a soft gel when exposed to your body heat after insertion. It is designed to accommodate to the size of any punctum canal. Advantages of this type of plug are that one size fits all so measurement is unnecessary, and nothing protrudes from the tear duct that could potentially cause irritation.

Sometimes, however, the tear ducts need to be closed surgically.

Doctors sometimes recommend special nutritional supplements for dry eyes. Studies have found that supplements containing certain essential fatty acids (linoleic and gamma-linolenic) can decrease dry eye symptoms.

If medications are the cause of dry eyes, discontinuing the drug generally resolves the problem. But in this case, the benefits of the drug must be weighed against the side effect of dry eyes. Sometimes switching to a different type of medication alleviates the dry eye symptoms while keeping the needed treatment. In any case, never switch or discontinue your medications without consulting with your doctor first!

Treating any underlying eyelid disease, such as blepharitis, helps as well. This may call for antibiotic or steroid drops plus frequent eyelid scrubs with an antibacterial shampoo.

Quite a few products are in testing for possible dry eye treatment. For example, trehalose (a carbohydrate) improved dry eye symptoms in small studies, but further testing is needed.

If contact lens wear is the cause of your dry eyes, your eye care practitioner may want to switch you to a different lens or have you wear your lenses for fewer hours each day. In a few cases, it is recommended that contact lens wear be discontinued altogether until the dry eye problem is cleared up.

If you are considering LASIK, be aware that dry eyes may disqualify you for the surgery, at least until the problem is resolved. Dry eyes increase your risk for poor healing after LASIK, so most surgeons will want to treat the dry eyes first, to ensure a good LASIK outcome. This goes for other types of vision correction surgery, as well.