Tears

Like detectives newly arrived at the scene of a crime, researchers today are picking up clue after clue toward the solution of one of life's enduring mysteries—the meaning of human tears. Consider just a few aspects of tearing now being investigated:

Tears have a more complex chemical composition than was imagined, raising the likelihood that they might act as one of the body's waste-disposal systems.

Emotional tears are chemically different from those caused by irritation, and may contain larger quantities of substances the body manufactures when under stress.

People in general feel better after crying. And those who cry more frequently and have better attitudes about crying may be less prone to such stress-related diseases as ulcers and colitis. Women cry more often than men do. This may have to do with body chemistry, as well as the greater license to cry that our society grants women.

Incredibly, many of these issues were not raised until recently. While the physical functions of tears—washing and protecting the eyes—were perhaps too obvious to arouse much scientific interest, the relationship between emotions and tears was generally left to poets and psychiatrists.

Researchers began to understand the tearing process only in the past 15 years or so. The eye is covered by a three-layer film—an inner mucoid layer that enables tears to spread evenly over the cornea, a middle watery layer that keeps the surface of the eye wet and optically smooth, and an oily outer layer that is believed to retard evaporation. The inner layer comes from cells on the eye's surface; the other layer is secreted by tiny glands located primarily in the lid margins, or edges, the watery layer we think of as tears coming from the lachrymal glands in the upper part of the eye socket.

By blinking an average of 16 times a minute, the eyelids sweep contaminants to the inner corner of the eye, where they exit with a small amount of tear fluid through tiny drainage channels. When, however, the lachrymal glands are responding to eye irritation or inward emotion, they can flood these channels to the point where fluid both drains into the nose and overflows the lids onto the cheeks.

Evidence from tear research may warrant a drastic change in our idea about crying. Although there is such a thing as people weeping to excess, crying in response to various emotions is a natural physical process that we should not be ashamed of.