Tears are produced from the lacrimal glands, which are present along the sides of the eyes; these glands open up at the medial end through ducts, they drip into the eyeballs, and the excessive tears are drained into the nasolacrimal duct into the nose. Tears formed through crying are associated with strong internal emotions, such as sorrow, elation, love, awe and pleasure. 

Laughing or yawning may also lead to the production of tears. Physiologically there is an increased tear production, when eyes have been insulted, with allergens, chemicals, drying, infections, inward-turned eyelids or even in-turned eyelashes.

All these insults irritate the corneal epithelium, as a protective measure, the tear sac releases the tears, to subside the insult. The tear production can be pathological too, in case of blocked duct systems due to inflammation or without any apparent reason which is termed as epiphora.

It is bothersome to have tear roll down your face all the time, moreover the stock up of the tears, makes the sac and ducts more prone to bacterial stagnation and infections. This issue is mostly face in the babies under 12months of age or in senior citizens. 

In babies abnormal tearing is due to non-patency of the duct systems, this usually subsides with time, or by simple manipulation by pressing down over nose few times can pave way for the tears down the ducts. In elders, a simple blocked duct, may require probing and rarely requires a surgery to drain tear adequately. Fortunately, the offending cause can be treated and a surgical approach is not needed.

-Koya Satyasri