Dry eyes occur when the system that produces your tears breaks down. This causes the cornea, or parts of it, to dry out. Symptoms include a stinging, burning, or scratchy sensation, stringy mucus in or around the eyes, increased eye irritation from smoke or wind, eye fatigue after short periods of reading, and difficulty wearing contact lenses. Both eyes are usually affected.
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| Eye Sight Problems |
Some people don't produce enough tears to keep their eyes comfortably lubricated. This may be due to aging, medications, menopause, autoimmune disorders, chemical burns or eyelid deformities. Other people produce a normal amount of tears, but the composition of the tears is of poor quality. That means the tears lack certain components, such as oil, that are essential for lubrication. Problems unrelated to tear production may also cause eyes to feel dry and scratchy. These include:
- Blepharitis
- Entropion or ectropion
- Environmental irritants such as smoke, sun, wind and indoor heating
- Disruption of your blink reflex
- An allergic reaction to eyedrops or ointment
- Eyestrain
Decreased tear production. Like skin and hair, your tear production tends to dry up as you get older. When you're unable to produce enough tears, your eyes become easily irritated. The medical term for this condition is keratoconjunctivitis sicca (ker-uh-tokun-junk-ti-VIE-tis sik-uh).
Although dry eyes can affect both men and women at any age, it is more common among women, especially after menopause. This may be due to hormonal changes brought on by this phase. Damage to the lacrimal glands from inflammation or radiation can hamper tear production. Dry eye is also associated with medical conditions such as rheumatoid arthritis, systemic lupus erythematosus (SLE), scleroderma and Sjogren's syndrome.
Poor tear quality. Tears are much more than just water. They are a complex mixture of water, fatty oils, proteins, electrolytes, bacteria-fighting substances and growth factors that regulate various cell processes. This mixture helps make the eye surface smooth and clear. Without it good vision is impossible.
The eyelids spread tears across the surface of the eye in a thin film. The tear film has three basic layers:
Mucus. The inner layer consists of mucus produced by the conjunctiva. This layer allows tears to spread evenly over the surface of the eye.
Water. The middle layer, which makes up about 90 percent of the tear, is mostly water with a little bit of salt. This layer, produced by the lacrimal glands, cleanses the eye and washes away foreign particles or irritants.
Oil. The outer layer, produced by glands on the edge of the eyelid, contains fatty oils called lipids. These smooth the tear surface and slow evaporation of the watery layer.
Considering this complicated mix of ingredients, it's not surprising that the balance is sometimes off. An imbalance causes the tears to evaporate faster and your eyes to become dry. Certain diseases or chemical burns can cause changes in the oily and mucous layers of your tears. Blepharitis, rosacea and other skin disorders also can disrupt production of the oily layer.
Treatment. If your eyes feel dry and irritated, your eye doctor can test both the quantity and quality of your tears. The doctor may measure your tear production using the Schirmer tear test. In this test blotting strips of paper are placed under the lower eyelids. After 5 minutes the amount of strip soaked by, the tears is measured.
Other tests use special dyes in eyedrops to determine the surface condition of your eye. The doctor looks for staining patterns on the cornea and measures how long it takes before your tears evaporate.
Regardless of the cause of dry eyes, the goal of treatment is to keep your eyes moist. This can be done either by replacing the tears or conserving them.
Adding tears. A mild case of dry eyes usually can be treated with artificial tears. You can use the lubricating drops as often as needed, even several times an hour to provide relief, if you use drops frequently, preservative-free eyedrops might be the best choice to avoid an allergic or toxic reaction to preservatives. People with dry eye districts are often more prone to irritation preservatives in eyedrops.
Ointments can be used to ensure lubrication. These ointments can blur vision, so it's best to use them only at night.
Conserving tears. Your eye doctor may also suggest methods to keep your tears from draining. The tear drainage ducts can be plugged either temporarily or permanently with tiny collagen or silicone plugs. The closure conserves both your own tears and artificial tears you may have added. Collagen plugs will slowly dissolve over a few days. Silicone plugs can be removed or left in. A more permanent option is thermal cautery. In this procedure the doctor numbs the area with an anesthetic and then applies a hot wire that shrinks the tissues of the drainage area and causes scarring, which closes the tear duct.
Anti-inflammatory drugs. Some evidence suggests that the underlying cause of dry eyes is an inflammation in the lacrimal glands and on the surface of the eye. For this reason researchers are investigating anti-inflammatory drugs for treating dry eyes. The results of one clinical trial suggested that people who received such a drug, cyclosporine A, experienced significant improvement in their dry eye symptoms with few side effects. When people experience intolerable irritation from dry eyes despite the frequent use of lubricating eyedrops, doctors may prescribe steroid drops.
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| Eye Sight Problems |
Self-care. Like any liquid, tears will evaporate when exposed to air. These are simple steps you can take to help slow evaporation:
- Don't direct hair dryers, car heaters, air conditioners or fans toward your eyes.
- Wear glasses on windy days and goggles while swimming.
- Keep your home humidity between 30 percent and 50 percent.
- In winter a humidifier can add moisture to dry indoor air.
- Remember to blink. Consciously blinking repeatedly helps spread your own tears more evenly.