Crying

There are three types of tears. The first type is basal tears. Because the eyeball's surface is riddled with irregularities, basal tears create a thin coat over the eye which smoothes out the surface. This helps to protect and lubricate the eye. Without this lubrication, a person would see a very distorted picture, and it would be painful when the eyeball moves. The eye needs this coating all the time so the body must constantly replace these tears due to the loss caused by evaporation. A typical person will produce five to ten ounces a day. In addition, basal tears contain antibacterial chemicals.

The second type is irritant tears. Irritant tears occur when a person is exposed to freshly cut onions or has a foreign object in his or her eye. They are called irritant tears because they are produced when a foreign object, foreign chemical, or a simple poke irritates the eye. The body will also produce more irritant tears if the basal tears evaporate too rapidly and the eye is left with an insufficient amount to properly lubricate the eye. Ironically, a person with excessively watery eyes suffers from having dry eyes. It is the irritant tears that cause the watery eyes because the body is compensating for the lack of basal tears.

The third type of tear is psychic or emotional. These are the tears that well up inside and spill over the eyelid because of specific emotional states. They are definitely more voluminous than the two types of tears previously mentioned, and they have been found to have a different chemical make-up. William Frey has shown that these chemicals are linked to depression and stress. Frey believes that crying is the body's attempt of ridding itself of these pollutants, thus reducing stress and avoiding depression.