Dry eyes can occur when tear production and drainage are not in balance. People with dry eyes either do not produce enough tears or their tears are of a poor quality:

• Inadequate amount of tears. Tears are produced by several glands in and around the eyelids. Tear production tends to diminish with age, with various medical conditions or as a side effect of certain medicines. Environmental conditions, such as wind and dry climates, can also decrease tear volume due to increased tear evaporation. When the normal amount of tear production decreases or tears evaporate too quickly from the eyes, symptoms of dry eye can develop.
• Poor quality of tears. Tears are made up of three layers: oil, water, and mucus. Each component protects and nourishes the front surface of the eye. A smooth oil layer helps prevent evaporation of the water layer, while the mucin layer spreads the tears evenly over the surface of the eye. If the tears evaporate too quickly or do not spread evenly over the cornea due to deficiencies with any of the three tear layers, dry eye symptoms can develop.

Dry eyes can develop for many reasons, including:

• Age. Dry eyes are a part of the natural aging process. The majority of people over age 65 experience some symptoms of dry eyes.
• Gender. Women are more likely to develop dry eyes due to hormonal changes caused by pregnancy, the use of oral contraceptives and menopause.
• Medications. Certain medicines, including antihistamines, decongestants, blood pressure medications, and antidepressants, can reduce tear production.
• Medical conditions. People with rheumatoid arthritis, diabetes, and thyroid problems are more likely to have symptoms of dry eyes. Also, problems with inflammation of the eyelids (blepharitis), inflammation of the surfaces of the eye, or the inward or outward turning of eyelids can cause dry eyes to develop.
• Environmental conditions. Exposure to smoke, wind and dry climates can increase tear evaporation resulting in dry eye symptoms. Failure to blink regularly, such as when staring at a computer screen for long periods of time, can also contribute to drying of the eyes.
• Other factors. Long-term use of contact lenses can be a factor in the development of dry eyes. Refractive eye surgeries, such as LASIK, can decrease tear production and contribute to dry eyes.

Avoid triggers by making changes to your home and your routine.

• Keep windows closed during high pollen periods; use air conditioning in your home and car.
• Wear glasses or sunglasses when outdoors to keep pollen out of your eyes.
• Use “mite-proof” bedding covers to limit exposure to dust mites, and a dehumidifier to control mold.
• Wash your hands after petting any animal.

Control some symptoms with nonprescription medications, sold over the counter:

• Artificial tears
• Decongestant eyedrops (don’t use eyedrops for “red eye” longer than a week, or they can make things worse)
• Oral antihistamines (note that they may dry your eyes and make your symptoms worse)

See an allergist for prescription medications, which may be more effective:

• Eyedrops (decongestant, antihistamine, mast cell stabilizer, corticosteroid, NSAID)
• Allergy shots (immunotherapy)
• Nonsedating oral antihistamines (note that they may dry your eyes and make your symptoms worse)