ABSTRACT

Excess tears either evaporate or drain through two small ducts on the inside corner of the upper and lower eyelids near to the nose-the lacrimal punctae. With each blink the tears wash away debris and potentially harmful bacteria into the nose. The production of tears, although a continuum, is varied by reflexes which produce a response when the eye is stimulated by bright light, by variation in temperature (hot or cold), by debris bombarding the eye (dusty atmosphere) or by emotion. Thus, when people cry the nose runs as the excess of tears pours into it through the lacrimal drainage system.