Dry eye syndrome is medically known as Keratoconjunctivitis Sicca and is defined as inflammation and drying of the Conjunctiva due to a lack of, or inadequate, tear production.
The front surface of the eye must be moist at all times in order to work properly. Your eyes normally make small amounts of tears all day long. Tears play several important roles in keeping your eyes healthy and your vision clear. Tears lubricate the eye’s surface, wash away debris, provide a smooth surface to help keep your vision clear, and also contain natural antibiotics that keep your eyes safe from germs that might cause infections.
Dry eye syndrome happens when your tears aren't able to provide adequate moisture for your eyes. Tears can be inadequate for many reasons. Some reason for inadequate tear production involves environmental factors such as air quality, working conditions, lack of water or proper hydration as well as antihistamines or other OTC cold medicines. Please feel free to read the other pages in this dry eye section for more information regarding
The tear film is made up of three separate layers. If any of the three layers is missing, or if your tears evaporate too quickly, you will develop dry eye syndrome. The three tear layers are:
Each layer of the tear film is made by a different part of the eye. The mucin layer is made by the eye surface itself. The aqueous layer is made by a tear gland tucked under the upper eyelid. And the lipid layer is made by small glands in the eyelids. For the tear film to do its job, all three layers have to be in their proper places in the correct amounts, like a recipe. If any layer is missing or abnormal—which can happen for a number of reasons—the tear film becomes disorganized and no longer soothes the eye as it should.
When that happens, the symptoms of dry eye syndrome occur. The front surface of the eye gets dried out (causing stickiness) and gets inflamed(causing stinging and burning). Once it gets inflamed, the eye ignores the proper tear film recipe and starts making large quantities of the aqueous layer in an effort to soothe itself. These bad tears don’t soothe the eye at all— they just run down your face, washing away the mucin and lipid layers as well. This makes the eye even more irritated, so it makes even more bad tears, and the cycle continues. For some people, the stinging and burning and redness and watering may seem like little more than a nuisance, but in fact, if left untreated, dry eye syndrome can lead to serious eye problems, including blindness. Dry eyes are inflamed eyes. Inflammation of the front surface of the eye increases the risk of some infections and can also lead to scarring. Once scarring occurs, permanent loss of sight can occur.
There are many causes of dry eyes, but the most common cause is simply getting older. As you age, your body produces less oil. This results in dry, irritated skin and also dry eyes. The eyes get dry because the oil layer of your tears is deficient, and the water in your tears evaporates too fast. Women are particularly vulnerable to dry eyes as they age because the hormonal changes that accompany aging often reduce tear production. Some systemic diseases, especially those in the autoimmune family, can cause or increase the severity of dry eye syndrome.
If your eyes frequently burn or feel itchy or scratchy, you may have dry eye syndrome, also known as chronic dry eye. People with dry eyes frequently experience burning and stinging of their eyes, their eyes often feel sticky, and are often red. You may feel like you have sand in your eyes. Your vision may be blurry.
Some people with dry eyes also have periods when their eyes get so watery that tears spill over their eyelids and run down their cheeks. It may sound strange for a dry eye to water excessively. This is because a dry eye is often irritated, and the eye is trying to soothe itself by making more tears. If your eye becomes dry and irritated because your tears are defective, then making lots more defective tears is no solution. You just end up with irritated, wet eyes.