Ophthalmology (Eye Diseases)
Dry eyes is a common condition that occurs when your tears aren't able to provide adequate lubrication for your eyes. Tears can be inadequate for many reasons. For example, dry eyes may occur if you don't produce enough tears or if you produce poor-quality tears.
Dry eyes feel uncomfortable. If you have dry eyes, your eyes may sting or burn. You may experience dry eyes in certain situations, such as on an airplane, in an air-conditioned room, while riding a bike or after looking at a computer screen for a few hours.
Treatments for dry eyes may make you more comfortable. These treatments can include lifestyle changes and eyedrops. You'll likely need to take these measures indefinitely to control the symptoms of dry eyes.
Symptoms of dry eyes
Signs and symptoms, which usually affect both eyes, may include:
- A stinging, burning or scratchy sensation in your eyes
- Stringy mucus in or around your eyes
- Sensitivity to light
- Eye redness
- A sensation of having something in your eyes
- Difficulty wearing contact lenses
- Difficulty with nighttime driving
- Watery eyes, which is the body's response to the irritation of dry eyes
- Blurred vision or eye fatigue
Causes of dry eyes
Dry eyes can occur when you're unable to produce enough tears. The medical term for this condition is keratoconjunctivitis sicca(ker-uh-toe-kun-junk-tih-VY-tis SIK-uh). Your tears are a complex mixture of water, fatty oils and mucus. This mixture helps make the surface of your eyes smooth and clear, and it helps protect your eyes from infection. Dry eyes can occur when you're unable to produce enough tears. The medical term for this condition is keratoconjunctivitis sicca(ker-uh-toe-kun-junk-tih-VY-tis SIK-uh).
For some people, the cause of dry eyes is decreased tear production. For others it's increased tear evaporation and an imbalance in the makeup of your tears.
Decreased tear production and common causes include:
- Certain medical conditions, including Sjogren's syndrome, allergic eye disease, rheumatoid arthritis, lupus, scleroderma, graft vs. host disease, sarcoidosis, thyroid disorders or vitamin A deficiency
- Certain medications, including antihistamines, decongestants, hormone replacement therapy, antidepressants, and drugs for high blood pressure, acne, birth control and Parkinson's disease
- Corneal nerve de-sensitivity caused by contact lens use, nerve damage or that caused by laser eye surgery, though symptoms of dry eyes related to this procedure usually are temporary
Increased tear evaporation
The tear film has three basic layers: oil, water and mucus. Problems with any of these layers can cause dry eyes. For example, the oil film produced by small glands on the edge of your eyelids (meibomian glands) might become clogged. Blocked meibomian glands are more common in people with inflammation along the edge of their eyelids (blepharitis), rosacea or other skin disorders.
Common causes of increased tear evaporation include:
- Posterior blepharitis (meibomian gland dysfunction)
- Blinking less often, which tends to occur with certain conditions, such as Parkinson's disease, or when you're concentrating during certain activities, such as while reading, driving or working at a computer
- Eyelid problems, such as the lids turning outward (ectropion) or inward (entropion)
- Eye allergies
- Preservatives in topical eyedrops
- Wind, smoke or dry air
- Vitamin A deficiency
Risk factors for dry eyes
Factors that make it more likely that you'll experience dry eyes include:
- Being older than 50
Tear production tends to diminish as you get older. Dry eyes are common in people over 50.
- Being female
A lack of tears is more common in females, especially if they experience hormonal changes due to pregnancy, using birth control pills or menopause.
- Eating a diet that is low in vitamin A or low in omega-3 fatty acids
Vitamin A is found in liver, carrots and broccoli, and omega-3 fatty acids are found in fish, walnuts and vegetable oils.
- Wearing contact lenses
Prevention of dry eyes
If you experience dry eyes, pay attention to the situations that are most likely to cause your symptoms.
Then find ways to avoid those situations in order to prevent your dry eyes symptoms:
- Avoid air blowing in your eyes.
Don't direct hair dryers, car heaters, air conditioners or fans toward your eyes.
- Add moisture to the air.
In winter, a humidifier can add moisture to dry indoor air.
- Consider wearing wraparound sunglasses or other protective eyewear.
Safety shields can be added to the tops and sides of eyeglasses to block wind and dry air. Ask about shields where you buy your eyeglasses.
- Take eye breaks during long tasks.
If you're reading or doing another task that requires visual concentration, take periodic eye breaks. Close your eyes for a few minutes. Or blink repeatedly for a few seconds to help spread your tears evenly over your eyes.
- Be aware of your environment.
The air at high altitudes, in desert areas and in airplanes can be extremely dry. When spending time in such an environment, it may be helpful to frequently close your eyes for a few minutes at a time to minimize evaporation of your tears.
- Position your computer screen below eye level.
If your computer screen is above eye level, you'll open your eyes wider to view the screen. Position your computer screen below eye level so that you won't open your eyes as wide. This may help slow the evaporation of your tears between eye blinks.
- Stop smoking and avoid smoke.
If you smoke, ask your doctor for help devising a quit-smoking strategy that's most likely to work for you. If you don't smoke, stay away from people who do. Smoke can worsen dry eyes symptoms.
- Use artificial tears regularly.
If you have chronic dry eyes, use eyedrops even when your eyes feel fine to keep them well-lubricated.