The benefits of tears

When we think of tears, we don't think of physical benefits to our health, but the benefits do exist. Here's how. 

•  When exposed to the air, our eyes need protection. A thin, transparent membrane called the conjunctiva, which covers the white of the eye and lines the upper and lower eyelids, stops the eyes from drying out.
• Tiny glands called lacrimal glands beneath the upper, outer corner of each eyelid continually secrete a watery tear fluid that is spread over the eye surface every time we blink, maintaining a constant moist layer and preventing damage from tiny particles in the air.
• In addition, even smaller glands called meibomian glands at the inner edge of the eyelids add an oily secretion that lubricates the eye and reduces evaporation of tear fluid.

• As well as the constant tear film that keeps our eyes moist, we produce excess tear fluid when we need to wash out irritants, such as specks of dust, or in response to injury, infection or allergies.
• The composition of these free-flowing tears is chemically different to the normal tear film — they contain more of an enzyme called lysozyme, a naturally antibacterial substance that helps to counteract infection. The concentration of lysozyme in tears tends to be low in children, increases until middle age and then falls off again, which may be why children and older people are more susceptible to eye infections.
• As we get older, tear production is often reduced and the tear film contains less of the oils needed to keep it from drying out — which may result in dry eye syndrome. This can make night driving difficult, as symptoms include a gritty sensation in the eyes, blurriness of vision and a dislike of bright lights.

• Crying can do you a world of good — and perhaps not just as an emotional release. Researchers have discovered that tears shed in extreme emotional situations have a higher protein content and more manganese and prolactin than ordinary tears or those produced, for instance, in response to peeling an onion.
• As we produce more manganese and prolactin when we're stressed, some scientists now believe that emotional tears may help to eliminate these and other stress-related chemicals.