Dry eye can result from an imbalance in the components of tears.

Overview

Dry eye syndrome is among the most common eye problems, and often results from the aging process, affecting nearly three in four people older than age 65. It is also more common among computer users, those with allergies to dust or pollen, contact lens wears, those with arthritis or certain immune disorders and those who work outdoors. Women are typically affected more often than men, as dry eye syndrome is triggered by hormonal changes such as post-menopause and during pregnancy or breast-feeding.

It also results from taking certain medications, including antidepressants, birth control pills, cold medications that act as antihistamines and decongestants, antihypertensives, antidiarrheals, acne medications and diuretics such as blood-pressure drugs. Dry eye is also a common but temporary side effect of LASIK, resulting from a disruption of the nerves of the cornea.

Dry eye occurs when there is a malfunction in one of more tear glands, or an imbalance in one or more of the three layers of tears:

• Oily layer, a thin outer tear layer produced in the meibomian and Zeis glands. These tiny glands line the edge of the eyelid and serve three purposes: To slow the evaporation of the watery middle layer; to increase surface tension so tears don't overflow the eyelid; and to lubricate the eye during blinking.

• Watery layer, the middle layer of the tear that comes from lacrimal gland, which lies beneath a bone near the nose, and the glands of Krause and Wolfring, which are on the inner surface of the eyelids. This layer works to supply oxygen to the eye's surface; to fight infection with natural antibiotics, such as lactoferrin and lysosomes; to act as a filling that smoothes the eye's surface; and to wash away debris such as dead cells and dust.

• Mucous layer , the innermost layer of the tear that originates in the goblet cells, Henle's crypts, and Glands of Manz. These glands are located in the conjunctiva, on the surface of the eye and inner eyelids. This thin layer helps tears glide evenly across the eye's surface. Without it, the other layers of tears would form into tiny droplets instead of a smooth, even coating.

Some people with dry eye experience “reflex tearing.” After experiencing the discomfort of extremely dry eyes, a substantial amount of tearing suddenly occurs. For example, if you stare for a long period without blinking, your eyes will dry out and reflex tearing will kick in, causing a significant amount of tears to pour out. These tears contain unbalanced proportions of the different layers of tears.

Symptoms

• Burning or itching eyes
• A feeling of grittiness, as if there was sand in your eyes
• Difficulty in wearing contact lenses comfortably
• In some cases, you may experience increased sensitivity to light or excessive tearing
• In extreme cases, vision may appear blurred

Prevention

• If you use a computer regularly, take a 10-minute break every hour or so to give your eyes a rest.
   
• Use a humidifier when you are indoors, since dry heat and lack of humidity can be aggravating. This is especially important if you use a hair dryer or are exposed to chemical vapors, smoke, air conditioning or similar environmental conditions.
   
• Avoid wearing contact lenses when you experience symptoms. If you must wear contacts, be sure to lubricate eyes more frequently with artificial tear products.
   
• Wear protective eyewear when outdoor during windy days or around dust, pollen or other irritants.

Treatment

• Replace the natural tears with artificial tears. In most cases, the solution for dry eye is artificial tears. These are different from drops that remove redness and can be purchased over-the-counter. Moisturizing ointment may be prescribed, and certain homeopathic eyedrops may help the body increase tear secretion.

  There are many types of artificial tears. If they are too thin, they will drain away or dry out too quickly. If too thick, they will blur vision. Some will have restrictions on the frequency of use. Read the labels carefully and try a few brands to determine which best suits your needs. Artificial tears usually solve the problem of mild to moderate dry eye. If they do not ease your symptoms, additional treatment may be necessary.

• Plug the eye's drain. Your eyecare practitioner may suggest plugging the punctum, or drain opening, on your lower eyelids. Blinking creates a vacuum that sucks tears into these drains, from where they travel through nasolacrimal ducts to the throat. These tiny silicone punctual plugs are inserted manually to block drainage, and are recommended for moderate to severe dry eye.
   
• Seal the eye's drain. Thermal cauterization will seal the punctum, blocking tear drainage permanently. In this procedure, using local anesthetic, the eye doctor inserts a hot wire into the punctum. The heat seals the drain. Scarring may occur, and the procedure is not reversible. A laser can be used to seal the punctum with less scarring, but there is a 20 percent change that the drain will reopen on its own.

Before considering medical approaches such as sealing and plugging the puncta, there are several “do-it-yourself” treatment methods you can try:

• Increase blinking. You may not be blinking enough, especially when working at a computer or reading for long periods of time. Try to blink more often, and take frequent breaks from using computers to avoid fatiguing your eyes.
   
• Massage your eyelids. A simple eyelid massage will stimulate the tear glands. Just place a warm washcloth over closed eyes and gently massage the upper eyelid against the brow bone for 5 to 10 seconds. Then massage the lower eyelid against the lower bone.
   
• Monitor your diet. Natural diuretics can dry your eyes (as well as the rest of your body). You may benefit from reducing or eliminating your intake of coffee, tea, cola, alcohol and chocolate. It’s also advised to drink at least 8 glasses of water each day to ensure proper hydration.
   
• Adjust your medications. Your healthcare provider may be able to lower the dosages or switching medications that can contribute to dry eye. These drugs include antidepressants, birth control pills, antihistamines, decongestants, antihypertensives, antidiarrheals, acne medications and diuretics such as blood-pressure drugs.
   
• Control your environment. Simple changes in your home or office may eliminate your dry eye symptoms, such as using a humidifier, installing incandescent lighting instead of fluorescent, turning down the thermostat, and avoiding smoke and allergens.
   
• Change your contact lens care regimen. When not disinfected or wetted properly, contact lenses can wick tears away from the eye. Be sure to follow all care instructions closely. Try switching brands of lens care products. Preservative-free products are usually gentler on your eyes.