What causes dry eyes?

What causes dry eyes?

Dry eye syndrome is a common problem caused by the tear film that lubricates the eyes. Tear films are made of three layers : The outer mucus layer which helps to coat the cornea, the middle aqueous layer which provides moisture and supplies oxygen and nutrients to the cornea and the inner lipid or oily layer that seals the tear film on the eye and helps prevent evaporation.

Tears are formed in several glands around the eyes. Water is secreted by the lacrimal glands, located under the upper eyelids.

Several small glands in the eyelids secrete oil and mucus layers. With each blink, the eyelids spread the tears over the eye.

Excess tears flow into two tiny drainage ducts in the corner of the eye by the nose.

In addition to lubricating the eye, tears are also produced as a reflex response to outside stimulus such as an injury or emotion.

However, reflex tears do little to soothe a dry eye, which is why someone with watery eyes may still complain of irritation.

The most common factor for dry eye syndrome is the natural aging process. This is more common in women, who tend to have drier skin then men.

Other factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people find their eyes getting irritated when reading or working on a computer. Stopping periodically to rest and blinking keeps the eyes more comfortable.

Contact lens wearers also suffer from eye dryness because the contact lens absorbs the tear film, causing proteins to form on the surface of the lens.

Women frequently experience problems with dry eyes as they enter menopause due to hormonal changes.

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