What is dry eye disease and how will I know if I have it?
Dry eye disease, also known as keratoconjunctivitis sicca (KCS), can be a painful and irritating condition due to irregularities of the eye’s tear film. This can happen for a variety of reasons.
What causes dry eyes?
As we get older, tear production decreases.
Contact lens wear:
Increases tear evaporation leading to irritation, redness and discomfort.
Hormonal changes in women:
Pregnancy, birth control pills, or menopause can cause dry eye symptoms.
Smoke, air pollution, air conditioning, wind, or cold, dry air can lead to KCS.
Effects of disease/medications:
Auto-immune diseases such as arthritis or lupus can lead to KCS. Medications to treat hypertension and other medical conditions can lead to dry eyes.
How common is dry eye?
Approximately sixty million people worldwide use artificial tears. It is estimated that close to five million people over the age of 50 suffer from chronic dry eye disease in the United States.
What are tears made of?
The pre-corneal tear film is comprised of three layers: the oily layer, the mucin layer and the watery layer. Any imbalance in the ratio of these three components can cause symptoms of dry eye disease.
What are some of the symptoms of dry eye disease?
Some of these symptoms include a dry, gritty feeling in the eyes that is often accompanied by burning and redness. Other symptoms can include sensitivity to light, heat or air conditioning, and discomfort when wearing contact lenses. If left untreated, the delicate tissue of the ocular surface can be damaged, leading to poor vision. The onset of dry eye may be a result of hormonal changes or inflammation of the surface of the eye or the glands that produce tears.
How does keeping my eye moist help me?
In a normally functioning eye, there is an anti-inflammatory component of the tears that keeps irritation to a minimum. When a component of tears is lacking and irritation is not controlled, the eye does not produce adequate tears. This causes the body’s immune system to activate a defense mechanism which leads to inflammation. This inflammation of the eye’s surface and the tear glands results in “abnormal” tears, and the common symptoms of dry eye. Since the tears are “imbalanced,” the irritated eye is not properly nourished or lubricated. This encourages the cycle of inflammation and dry eye symptoms to continue.
The tear film also has antibacterial function, and a lack of tears can increase the possibility of infection.
If my eyes tear, how can they be dry?
Eyes are lubricated by two types of tears; lubricating tears and reflex tears. Lubricating tears are produced continuously to moisturize the eye and contain infection-fighting compounds.
Reflex tears are produced in response to sudden irritation (smoke, dryness, irritation) or emotion. Ironically the irritated, dry eye causes reflex tears to flood the eye. Since reflex tears do not have the proper ratio of components of lubricating tears, the discomfort persists.
How can dry eye be detected?
Dry eye disease can be detected by a thorough medical history, examining whether a patient has environmental influences that may cause dry eyes such as excessive air conditioning or heating, a smoke filled environment, or spending a lot of time in front of the computer, television or reading. Several tests in the examination room are also very helpful in the diagnosis. These include Schirmer tests, slit-lamp examination and staining of the corneal tissue and tear film.
What treatments are available for chronic dry eye disease?
Punctal plugs: These microscopic devices block the exit of tears from the surface of the eye, thereby creating a more humid environment. By keeping the tears from draining too quickly, the ocular surface is wetter, which can lead to relief. The procedure to insert plugs is quick, painless, and reversible. They are made of soft silicone and are almost invisible to the naked eye.
In December of 2002, the U.S. Food and Drug Administration (FDA) approved a topical cyclosporine ophthalmic emulsion, which has been shown to be helpful in treating the inflammatory changes that can accompany dry eye disease.
Several other treatments including INS365 and androgen- containing eyedrops are currently undergoing evaluation by the FDA and will hopefully become available.
Research has also shown that omega-3 fatty acids can help treat KCS. These are essential fatty acids that the body cannot produce and must be obtained from the diet. Americans typically do not eat enough salmon or other cold water fish which have been shown to be one of the best sources of omega-3. These, along with flax seed oil and EPA, (another natural source of omega-3s) have been shown to have a multitude of health benefits.
Omega-3 fatty acids can be helpful via three mechanisms: *
The first mechanism by which omega-3 fatty acids help improve dry eye is by decreasing inflammation. It has been shown in several studies that consumption of omega-3 fatty acids decrease the inflammation seen in joints with rheumatoid arthritis and in skin with dermatitis. Omega-3 fatty acids will also decrease meibomitis (inflammation of the oil glands that make up the oily layer of the tear film). As a result, patients with meibomitis taking omega-3 supplements have experienced varying degrees of relief from eye irritation.
The second mechanism is by augmentation of the oily layer produced by the meibomian glands. Studies have shown that the lipid make-up of the meibomian glands in female patients with Sjogren’s syndrome is influenced by the amount of omega-3 fatty acids consumed. Clinical reports have observed clearer and thinner oil films in the tears of patients taking omega-3 fatty acids. This allows for better flow and creates a better oil layer covering the tear film.
The third mechanism is via stimulation of the watery portion of tear secretions. The level of omega-3s acts on certain receptors to activate adenylate cyclase which has been shown to stimulate tear production.
By decreasing inflammation and augmenting the oily and watery layers of the tear film, omega-3 supplementation with fish oil containing EPA and flax seed oil helps to provide the foundation for the treatment of dry eye. This, coupled with the use of cyclosporine-containing eye drops, artificial tears, and punctal plugs, will help to serve the dry eye patient.
* You should consult your physician before taking vitamins, minerals, health nutritional supplements or herbal products.