Disorders of Tear Production

Tears aid normal vision, provide a smooth surface on the outside of the eye that helps clear debris while blinking, and nourish the eye surface. Tears normally drain or evaporate at the same rate at which they are produced; thus people are unaware of the tears in their eyes. But when production and elimination of tears are not in balance, dry eyes or excessive tearing can result. Both conditions are common in older people. Tearing is also a reflex to dryness of the surface and can actually be an indication that the eye is dry.

Dry Eyes

Dry eyes are common among older people because tear production decreases with aging, especially among women. Exposure to a dry climate or to cigarette smoke can worsen the condition. Drugs are a common cause of dry eyes, as are eyelid disorders, especially blepharitis. Less common causes include eye infection and, in developing countries, vitamin A deficiency. The most serious cause of dry eyes is Sjögren's syndrome, an uncommon autoimmune disease that also causes dry mouth and sometimes arthritis.

A doctor diagnoses dry eyes by collecting tears with a special paper strip placed next to the eyeball. Sjögren's syndrome is diagnosed with the use of blood tests and possibly a biopsy. Regardless of the cause, treatment is with artificial tears. Other treatments, such as the surgical placement of plugs in the drainage canals to decrease tear drainage, are needed only if artificial tears do not relieve symptoms or maintain the health of the eye surface.

Excessive Tearing

Excessive tearing can be caused by impaired drainage of tears or as a reflex when the eye surface is dry. An improperly positioned lower eyelid or an obstruction of the drainage ducts in the eyes or nose can impair drainage. The doctor probes and irrigates the drainage ducts if obstruction is suspected; otherwise, no tests are necessary. Treatment usually involves treating the underlying cause.