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August 27, 2008
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Dry EyesDry Eye SyndromeIn a world bombarded by air conditioners, pollution, and cigarette smoke, few people have been spared from the irritating symptoms of dry eyes. Most people only suffer from mild dry eyes, an eye condition that is easily managed with artificial tears. There is a large percentage of the population (10 million Americans), however, who suffers from much more severe dry eye. Do your eyes feel dry, irritated, and painful? If so, there is a chance that you suffer from dry eye syndrome. Dry eye occurs when there is a problem with the stability of the tear film that covers the surface of the eyeball. Tears are comprised of three different layers, each of which is produced at a different location. The mucous layer is the layer of the tear film that is closest to the epithelium of the cornea and is actually produced by these epithelial cells. The mucous layer provides a surface to which the aqueous layer of the tear film can adhere. The aqueous layer is produced by the lacrimal gland (as well as accessory lacrimal glands). It is the thickest layer of the tear film and provides the cornea with oxygen and nutrients. The outermost tear film layer is produced by the meibomian glands and is known as the lipid layer. Its primary function is to prevent evaporation. The tear film is regenerated with each blink, which maintains moisture and renews nutrients and oxygen supply to the surface of the eye. Tears flow across the surface of the eye and drain through two tiny holes (puncta) that are located on the upper and lower eyelids. If there is a problem at any point along the life cycle of the tear film, dry eye syndrome may be the consequence. Problems with tear production can take place at any of the three different locations where the layers of tear film are produced. A decrease in tear production is actually a natural aging process: as we age, the body produces up to 60% less oil. For this reason, many older people suffer from dry eye. Without the necessary oily outer layer of the tear film, increased evaporation of the tear film leads to symptoms of dry eye. Alternative causes for dry eye syndrome include contact lens wear; hot, windy, and dry climates; high altitudes; computer vision syndrome; vitamin A deficiency; and thyroid medications, and Sjogren's syndrome. Sjogren's SyndromeSjogren's syndrome is a chronic eye disease in which white blood cells attack the moisture-producing glands (eg. tear glands and salivary glands), resulting in severe dry eye symptoms. Classic symptoms of Sjogren's are dry eyes and a dry mouth. Rheumatoid arthritis is one of the causes of Sjogren's syndrome, as is Lupus. Signs & Symptoms of Dry Eye SyndromeDry eye symptoms are variable in both type and severity, but some of the most commonly experienced symptoms include the following:
Detection & Diagnosis of Dry Eye SyndromeThere are a number of diagnostic tests at an optometrist's disposal to assess dry eye, most popular of which is an assessment of tear film stability and evaporation rate using a fluorescent dye called sodium fluorescein. Sodium fluorescein is bright yellow in color and is applied directly to the eye. The optometrist views the eye under cobalt blue illumination and asks that patient to stop blinking as long as possible. In places where the tear film breaks down, the eye doctor will see a change in the tear film. This test measures tear break-up time (TBUT). The Schirmer Test is another test that measures tear production. It is a somewhat uncomfortable test in which small pieces of paper are placed at the outer edges of each eye and left there for one minute. The distance along which the paper becomes moistened is a measure of tear production. Further tests help to determine quality, production, and evaporation of tears. Dry Eye Syndrome TreatmentTreatment of dry eye depends on the needs of each patient. The primary method of treatment for dry eye is artificial tears. These tears are composed of a solution very similar to natural tears and can be applied as liberally as needed. The problem, however, is that they provide only temporary relief from dry eye. For individuals who experience dry eye intermittently, artificial tears are the best option. An alternative to artificial tear eyedrops is ointment. Ointments provide longer-lasting dry relief, but unfortunately have the unwanted side-effect of causing temporary blurred vision as they form a coating over the surface of the eye. When shopping for artificial tears, avoid solutions that treat eye redness. Many of these solutions actually cause dry eyes. More permanent solutions to dry eye take the form of punctal plugs (or lacrimal plugs), which are tiny pellet-like cylinders made up of either collagen (temporary plugs that break down) or silicone (permanent plugs). The plugs are placed into the tiny holes (puncta) at the inside corner of each eyelid. By plugging the drainage hole for tears, the tears will remain on the surface of the eye longer, keeping it moist. Prevention of Dry Eye SyndromeThe best way to prevent dry eye is to avoid substances and environments that cause it. Avoid polluted, air-conditioned, smoky environments as much as possible. Simply keeping hydrated can also help to prevent dry eye. Omega-3 and Omega-6 fatty acids have also been found to have a significant impact on maintaining healthy eyes and preventing dry eye. Omega-3 is found in cold water fish and Omega-6 is found in raw nuts, seeds, and grape seed oil, among other sources. DisclaimerThe information provided by KnowYourEyes.com is intended for educational purposes only and in no way replaces the advice and diagnosis of a licensed eye care professional. KnowYourEyes.com disclaims any and all liability for injury or other damages that may result from use of the information obtained from this website.
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