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Dry Eye Syndrome
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Do you suffer from dry eyes? If you answered “yes”, you aren’t alone. It is estimated that 10 – 40 million people in the United States suffer from this condition. Dry eye syndrome defined as a decline in the quality or quantity of tears necessary to lubricate the eye. If left untreated, severe dry eye can lead to scarring or ulceration of the cornea, and subsequent loss of vision. Symptoms of dry eye include persistent dryness, scratching, or burning, and some may experience a “foreign body sensation”, the feeling that something is in the eye. There may even be too much watering in the eyes since the eyes will water or tear excessively as a reflex response to the dryness and irritation.
To better understand dry eye, it may be helpful to learn about the anatomy of the tear film. In a normal eye, several glands of the ocular anatomy function to produce tears and a tear film. Tears, produced by the lacrimal gland, bathe the eye, washing out dust and debris. The tear film is made up of a complex combination of substances that form three layers on the eye, an inner mucin layer, a watery (aqueous) middle layer, and an oily outer layer (see figure 1). When a component of the tear film is deficient or when too few tears are produced, the tear film breaks down producing dry spots on the cornea that cause symptoms of dry eye.
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Tear Film |
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The very thin
outer layer contains lipids and is produced by tiny glands in the eyelid called meibomian glands. This outer layer functions to reduce tear evaporation. |
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The lacrimal glands produce the
middle, watery layer of tears and are located at the upper outer region of the bony orbit above the eyeball. This gland keeps the salinity (level of salt and water) and acidity of the tears at proper levels. This layer also carries antibodies and other immune defense agents to defend the eye against infection. |
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The inner mucin layer helps the tear film to “stick” to the cornea and stay intact. Deficient production of the mucin layer interferes with the even distribution or spreading of the tear film across the corneal surface. |
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Figure 1
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What Causes Dry Eye? |
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AGING
decreases the production of tears. This is especially true for women after menopause. |
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CONTACT LENS WEAR
can increase tear evaporation causing irritation and discomfort. |
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ENVIRONMENTAL CONDITIONS
such as sun, wind, dry air, dust, smoke, air pollution, and pollen can cause dry eye symptoms. |
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MEDICATION
such as anti-histamines, diuretics, anti-depressants, and birth control pills can cause decreased tear production. |
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COMPUTER USE
causes decreased blink frequency – about 7 times per minute verses a normal rate of 20 times, leading to increased tear evaporation. |
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LASER EYE SURGERY
can cause the nerve endings of the central cornea to be severed, causing less sensitivity and decreased blink reflex; tear film evaporation increases and tear production is reduced. |
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CERTAIN SYSTEMIC CONDITIONS
such as rheumatoid arthritis, lupus, rosacea, Sjogren’s syndrome, and menopause. |
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Treatment for Dry Eye
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| While dry eye cannot be cured, it can certainly be managed. Many find relief from the symptoms of dry eye by using artificial tears on a regular basis (figure 2). Some artificial tear products are watery and alleviate the symptoms temporarily; others are thicker, adhere to the eye, and may last longer but also potentially blur vision. Preservative-free tears are recommended because they are the most soothing and have fewer additives that can irritate an already compromised cornea. Even new “disappearing preservatives” can be potentially toxic, so if you use an artificial tear product, look for one that is truly preservative-free. There is an
artificial tear product available that is truly preservative-free and provides antioxidants for protection from free radicals. Also, for dry eye, avoid products that whiten the eyes – they don’t have adequate lubricating qualities and often make the problem worse. |
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Figure
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| People who experience dry eye due to “meibomitis” (the infection and inflammation of oil glands in the eyelids) can be treated with antibiotics and warm compresses to help “melt” the lipid plug. It is thought that the meibomian glands get clogged up due to changes in hormonal levels that cause a thickening of the oils (see figure 3). |
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Figure
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| Some forms of dry eye benefit from the placement of tiny plugs in the ducts that drain tears from the eye. Closing the opening of the tear drain in the eyelid with special inserts called punctal plugs is another option. This works like closing a sink drain with a stopper. These special plugs trap the tears on the eye, keeping it moist. This may be done on a temporary basis with a dissolvable collagen plug, or permanently with a silicone plug (see figure 4). |
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Figure
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| There are also simple lifestyle changes that can significantly improve irritation from dry eyes. For example, drinking eight to ten glasses of water each day keeps the body hydrated and flushes impurities. Make a conscious effort to blink frequently – especially when reading or watching television. Avoid rubbing the eyes as this only worsens the irritation. Use a quality professionally recommended eye care
product for Dry Eye. |
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Figure
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Treating dry eye symptoms is important for
short-term comfort and the long-term health of your cornea.
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| Note: All information on this website is intended for your general knowledge only and is not a
substitute for medical advice or treatment for a specific medical condition. Please consult your
physician if you have questions or concerns regarding your health. |
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