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Dry Eyes |
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Tear film is a very essential part of the eye and is responsible for clear vision and comfort. Tears are constantly produced to keep the surface of the eye moist and as a clear medium for effective functioning of the eye as an optical medium. Tears are protective and lubricating to the eye. And they also reduce infection and wash the debris away.
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Signs and Symptoms
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“Dry eyes” is a very common condition and a common source of irritation, discomfort and very common after 40 years of age. Both eyes are usually affected. Common symptoms include
- Foreign body sensation in eyes.
- Stinging, burning, irritating and scratching sensation with stingy mucus in and around eyes especially on exposure to smoke, wind and air-conditioned environment.
- Eyes feel fatigued after a short period of time, after short periods of reading .
- Increased sensitivity to light associated with blurred vision, worsening towards the end of the day or after a prolonged near work like reading, computer etc.
- Difficulty wearing contact lenses .
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Causes:
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Dry eyes can be due to poor quality of tears due to change in the composition of the tears or can also be due to insufficient production of tears as such. Eyelid problems, medications and other causes, such as environmental factors, also lead to dry eyes.
Poor tear quality: The tear film has: oil, water and mucus. Problems with any of these layers can cause dry eye symptoms.
- Oil. The outer layer of tears produced by of secretion from small glands on the edge of lids called meibomian glands. This layer keeps the surface of the eye smooth and prevents excessive evaporation of tears from the eye. When this oil layer is abnormal, the watery layer evaporates too quickly. Dry eye problems are common in people whose meibomian glands are clogged. Meibomian dysfunction is more common in people with inflammation along the edge of their eyelids (blepharitis), rosacea and other skin disorders.
- Water. The middle layer, which makes up about 90 percent of tears, is mostly water with a little bit of salt. This layer, produced by the tear glands (lacrimal glands), cleanses your eyes and washes away foreign particles or irritants. If your eye produces only small, inadequate amounts of water, the superficial oily layer and deep mucus layers can come in contact and cause the stringy discharge familiar to people with dry eyes.
- Mucus. The inner layer of mucus allows tears to spread evenly over the surface of your eyes. Dry spots form easily in any part of the cornea that has patchy loss of the mucus layer.
Decreased tear production: Tear production tends to diminish as you get older. Insufficient production of tears is called Keratoconjunctivitis sicca and can cause severe dry eye. The condition is more common among women, especially after menopause. This may be due in part to hormonal changes. Damage to the tear glands from inflammation or radiation can hamper tear production. Dry eyes are also associated with medical conditions such as diabetes, rheumatoid arthritis, lupus, scleroderma and Sjogren's syndrome.
Refractive eye surgeries such as LASIK also may cause decreased tear production and dry eyes. Symptoms of dry eyes related to these procedures usually resolve after several months.
Poor lid function: Blinking spreads the tear film across the surface and poor lid function can affect spreading of tear film resulting in dry eyes. Eyelid problems which can affect the tear film spreading include ectropion (outward turning of the eye lid) and entropion (inward turning).
Blepharitis, an inflammation along the edge of the eyelids, also may cause your eyes to feel dry and scratchy.
Medications: Some medications can also cause dry eyes, such as:
- Diuretics, drugs commonly used to treat high blood pressure
- Antihistamines and decongestants
- Sleeping pills and birth controlling pills
- Tricyclic antidepressants
- Isotretinoin-type drugs for treatment of acne
- Opiate-based pain relievers such as morphine
Other causes of dry eyes: Dry eyes can be worsened by exposure to many environmental conditions that have a drying effect, such as sun, wind, high altitude, a dry climate, hot blowing air and the dry air that commonly occurs in the cabins of commercial airplanes.:
In addition, tasks that require intense visual concentration — such as working at a computer, driving or reading — tend to decrease your blink rate, thereby increasing tear evaporation.
In some people, the cause of dry eyes is an allergic reaction to eye drops or ointments.
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Treatment
Dry eyes don’t usually cause permanent damage, but prolonged dryness not responding to routine measures of lubrication associated with painful eyes, needs to be seen by the eye doctor.
Dry eyes can be diagnosed by performing tests like Schirmer’s tear test, rose Bengal staining and tear breakup time.
- Managing lid problems. Eyelid conditions mentioned above need to be attended thoroughly, and this may mean surgery in severe cases of dry eyes to correct the lid problem. Blepharitis, may need regular cleaning of the area with a dilute solution of baby shampoo and also short-term, nightly treatment with antibiotic drops or ointment or treatment with an oral antibiotic such as tetracycline or doxycycline.
- Adding tears. Usually helps in treating a mild case of dry eyes with artificial tears like Refresh, Tears Plus, Genteal and Eyemist. You can use the lubricating drops as often as you need to provide relief. Ointments are used at night to ensure lubrication. These ointments can blur vision, so it's best to use them only at bedtime.
- Conserving tears. This can be done by partially or completely closing your tear ducts, which normally serve to drain tears away. The tear ducts can be plugged with tiny silicone plugs. A more permanent option is thermal cautery. People with mild dry eyes respond well to treatment with artificial tears.
- Cyclosporine. Can be used to treat severe cases of dry eyes.
Severe not responsive dry eyes may rarely be due to autoimmune conditions like Sjogren’s syndrome.
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Self-care
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Like any liquid, tears will evaporate when exposed to air. You can take these simple steps to help slow evaporation:
- Avoid air blowing in your eyes. Don't direct hair dryers, car heaters, air conditioners or fans toward your eyes.
- Wear glasses on windy days and goggles while swimming. The wraparound style of glasses may help reduce the effects of the wind.
- Keep your home humidity between 30 percent and 50 percent. In winter, in cold climates a humidifier can add moisture to dry indoor air. Some people use specially designed glasses that form a moisture chamber around the eye, creating additional humidity.
- Avoid rubbing your eyes. You can irritate your eyes further by rubbing them.
- Take preventive steps. Use eye drops before, rather than after, your eyes become irritated as a result of visually demanding activities. Try to avoid activities that might worsen the problem.
- Remember to blink. Consciously blinking repeatedly helps spread your own tears more evenly. When performing tasks that require intense visual concentration, take occasional breaks — adding up to about five minutes each hour — and rest your eyes by closing your lids for several seconds. Follow this by consciously increasing your blink rate. Be especially careful to follow these suggestions if you have had LASIK or a similar procedure.
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