dry eye causes

Surprising Causes of Dry Eyes

A healthy adult produces tears every minute during waking hours. Tears protect and lubricate the surfaces of the eyes (corneas), remove dust and other particles, and flush out inflammatory chemicals that accumulate when the eyes are irritated.

But about 15% of Americans over age 65 suffer from dry eyes. The problem occurs most often after age 50, as our tear production declines with age. Symptoms of dry eyes include stinging or burning sensations… eye fatigue when reading… mucus in or around the eyes… or the sensation that there’s sand or gravel in the eyes.

What most people don’t know: Tears help people see. By spreading across the eye surface to create a “tear film,” tears work in tandem with the cornea to provide the major optical surface. That’s why long-distance vision may be impaired in people who have chronic dry eyes.

If you think you have dry eyes, see an ophthalmologist (a medical doctor who specializes in eye diseases and surgery). He/she usually can diagnose dry eyes after taking a medical history and noting your symptoms. There may not be a cure for dry eyes, but treatment can minimize discomfort and help protect your vision.

CAUSES OF DRY EYES

Tears are composed of 90% water and small amounts of salts or electrolytes and proteins that are secreted by the lacrimal glands located at the top outer edge of each eye. Tears also contain mucus and blood fats (lipids) produced by the meibomian glands located on the edge of the eyelids.

Main causes of dry eyes…
Blepharitis. This inflammation of the eyelids is often caused by a blockage of the lipid-producing meibomian glands or by the secretion of oils that are unusually thick and don’t flow properly.

Medications. Many prescription and over-the-counter (OTC) drugs cause dry eyes. Main offenders: Antihistamines, decongestants, diuretics and some antidepressants, such as amitriptyline (Elavil). If you experience dry eyes after starting a new medication, talk to your doctor about alternatives.

Inflammation. When allergies or exposure to environmental irritants, such as dust or wind, or chemicals found in household cleaning products irritate the eyes, cells release inflammatory chemicals called cytokines. In normal eyes, the flow of tears dilutes the concentration of inflammatory cytokines and may counteract their effect, thereby reducing irritation. But in allergy sufferers and other people with chronic inflammation, there aren’t enough tears to dilute the cytokines. Treating allergies or other sources of eye irritation may eliminate dry eyes — but not always.

Sjögren’s syndrome. This autoimmune disease occurs when a person’s antibodies damage the lacrimal glands, which reduces tear production. Drug treatments for Sjögren’s help relieve dry eyes, but do not cure them.

DIAGNOSIS AND TREATMENTS

If you’ve been diagnosed with dry eyes, here are the best ways to treat the condition…

Lubricate the eyes. Patients who experience only mild dryness of the eyes usually can get relief by using “artificial tears” one to four times daily. These OTC products are available in liquid and gel forms. Both are equally effective.
Caution: The preservatives, such as benzalkonium chloride, added to many products can damage eye cells if used more than four times daily. For more frequent use, choose a preservative-free product, such as Refresh Liquigel, Systane or Tears Naturale Free, or one with a “vanishing preservative,” such as GenTeal. The preservative disappears as soon as the drops come into contact with the tear film.

Reduce inflammation. People with inflammatory conditions, including Sjögren’s syndrome, may require anti-inflammatory medications to diminish dryness. Steroid or immunosuppressant eye drops, such as cyclosporine (Restasis), control the inflammation response and significantly reduce dry eye symptoms in many patients. These drugs are typically used for a few months to several years.
Caution: Because topical steroids can cause an increase in eye pressure and cataracts, patients must have their eye pressure measured monthly while using these drops.

Wear “moisture chamber” eyeglasses. They are designed to create a high-humidity environment by fitting snugly to prevent moisture in the eyes from evaporating. They also minimize exposure to wind or dust. Some patients can get by with tight-fitting, wrap-around sunglasses. If these don’t help, an eye care professional can make special moisture-chamber glasses. Cost: Up to $100 in addition to the cost of the lenses and frames. Many insurance policies pay for them.
Also helpful: Put a humidifier or vaporizer beside your bed, desk or any area where you spend a lot of time.

Practice blinking. Four times a day, blink 20 times. Many people with dry eyes experience subconscious discomfort when they blink — as a result, they get in the habit of not blinking completely. Blinking is essential because it causes the eyes to secrete protective oils… wipes away dead skin cells… and increases tear production.

Take an omega-3 supplement. The omega-3 fatty acids found in cold-water fish and flaxseed have anti-inflammatory effects and often reduce eye dryness. Because it can be difficult to get adequate amounts of these essential fatty acids in your diet, I recommend taking TheraTears Nutrition or Ultimate Omega capsules, formulas that contain a good mix of fatty acids for eye health. Such products are usually found in the eye-care section of pharmacies. Take two capsules twice daily.
If your dry eyes don’t improve enough with these therapies, you may be advised to undergo punctal occlusion, a simple outpatient procedure in which the tear drainage ducts are either sealed with silicone plugs or permanently closed. This causes tears to remain in the eyes longer and can reduce dry eye symptoms by up to 50%. Possible side effects include watery eyes and increased inflammation.
Caution: This procedure should only be done if your doctor determines there is no eye inflammation. Otherwise, inflammatory chemicals stay in contact with the eyes longer and increase irritation.

Author: J. Daniel Nelson, MD
Professor of ophthalmology at the University of Minnesota, and associate medical director of HealthPartners Medical Group & Clinics, both in Minneapolis.

VIDEO: Dry EYE Syndrome