If your eyes sting, itch or burn, you may be experiencing the
common signs of "dry eye." A feeling of something foreign within
the eye or general discomfort may also signal dry eye. What is
dry eye? Dry eye describes eyes that do not produce enough
tears. The natural tears that your eyes produce are composed of
three layers: • The outer oily layer, which prevents or slows
evaporation of the tear film • The middle watery layer; which
moisturizes and nourishes the front surface of the eye • The
inner mucus layer, which helps maintain a stable tear film. Dry
eye may occur because the volume of tears produced is inadequate
(we all produce fewer tears as we get older, and in some cases
this can lead to dry eye symptoms). It may result because the
composition of the tears has changed so that they are unstable
and evaporate more quickly. What causes dry eye? Dry eye
symptoms can result from the normal aging process. Exposure to
environmental conditions, as well as medications, such as
antihistamines, oral contracept