Dry Eye Syndrome is a condition caused by the reduction in quality and quantity of tears. Dry eyes can cause mild irritation to extreme pain depending on the severity of the condition. Treatment typically involves artificial tears and lubricating gels or ointments and occasionally prescription eye drops.

Closure of the tear drainage system (punctal occlusion) may also improve symptoms, in some cases. Dry eyes affect millions of people throughout the world. The condition is most common in women after menopause, but it can affect both sexes and all age groups.

Symptoms of Dry Eyes

• Foreign body, sandy or gritty feeling

• Burning

• Itching

• Redness

• Blurred vision that improves with blinking

• Excessive tearing

• Increased discomfort after periods of reading, watching TV, or working on a computer

Causes of Dry Eyes

There are many causes of dry eyes. Aging is certainly a factor; as people age, they secrete fewer tears, leading to dryness. Hormones probably play a role, as dry eyes are also more common in women than men, especially post-menopausal women. Systemic diseases, like Sjogren's syndrome, rheumatoid arthritis, lupus, and diseases of the eye that affect the eyelids, the eye's surface or the cornea can also cause or aggravate dry eyes. Similarly, conditions, which affect the eye’s ability to close or to blink completely, also dry out the surface of the eye.

Antihistamines, tranquilizers, high blood pressure, and heart medications, and other types of drugs can lead to dry eyes. Even the topical artificial teardrops used to treat dry eyes can actually aggravate the condition, due to the detergent-like preservatives they contain.

There is a decrease in tear production following Lasik and PRK (Photorefractive Keratectomy) that can persist 3-6 months. This can be significant enough that it requires frequent administration of artificial tear substitutes.

The Tear Film

The tear film protects the eye by cleansing and flushing harmful chemicals and environmental contaminants from the surface. This anti-infectious film, which covers the surface of the eye, has three-layers.

The outer or lipid layer is very thin and oily. This layer, which floats on the surface of the tear film, is secreted by the meibomian glands located just behind the lashes in the lids. The outer layer prevents evaporation of the tear film; abnormalities and diseases of the eyelids, such as blepharitis, styes, and chalazia, cause increased evaporation and dry eyes.

The middle or aqueous layer is secreted by the lacrimal glands and accounts for most of the tear film. It is made up of primarily water. This layer provides the eye surface with oxygen and various nutrients. Sjogren's syndrome, a systemic disease characterized by dry eyes and dry mouth, affects the lacrimal gland leading to a decrease in aqueous tear secretion.

The inner or mucin layer is secreted by goblet cells normally present on the surface of the eye. This layer coats the eye's surface (epithelium) with a substance called mucin, which enables tears to "stick" to the surface of the eye. Deficiencies in mucin can cause dry eyes in patients with eye disorders caused by chemical injuries, Steven-Johnson syndrome, and ocular phemphigoid and systemic diseases caused by nutritional deficiencies.

The eyelids are also important in maintaining the tear film. Eyelids, which open and close normally, spread tears over the surface of the eye (epithelium). That does not occur in patients with abnormal lid position, poor lid closure, or an incomplete blink.

The Surface of the Eye

The epithelium keeps bacteria and other microorganisms, chemicals and pollutants from entering the eye. Damage to the surface of the eye accounts for the pain, foreign body sensation, difficulties with bright lights, decreased or blurred vision, increased risk of infection and problems with allergic or toxic reactions to topical eye drops in patients with dry eyes.

Treatment of Dry Eyes

Initially, dry eyes are usually treated with topical lubricating drops (artificial tears). Some artificial tears are water based and short acting; others are gel based lasting longer. Each individual may respond differently to treatment, some only requiring a couple drops a day, others requiring drops every one to two hours, and ointment at night. Use of preservative free artificial tears is recommended because the preservatives in tears can irritate the eyes, and on occasion make things worse.

If discomfort continues, the next step is closing the tear drainage ducts. This is done with silicone or collagen plugs inserted in the tear ducts, which can be removed if needed. This treatment blocks the absorption of natural or artificial tears allowing them to lubricate the eye longer. At times, permanent cattery occlusion may be done. Treatment with low dose cyclosporine drops can also be tried. This prescription medicine is believed to increase the production of ones own natural tears. Many dry eye sufferers have found relief with this treatment

Finally, there are simple lifestyle changes that should be adopted. For example, drinking eight glasses of water a day will hydrate the body and thereby improve tear production. While reading or doing computer work, the dry eye sufferer should consciously try to blink more. Avoiding environments where smoke, dust, debris, or chemical fumes are present can also help. Protecting the eyes from the sun by using sunglasses or hats should also be routine. For some sufferers use of fish oil supplements has also been helpful.