What causes the production of tears in response to irritation?

The production of tears in response to irritation is primarily caused by the activation of the lacrimal glands. These glands, located in the upper outer region of each eye, are responsible for the secretion of lacrimal fluid (tears) to keep the eyes moist, provide nutrients, and help wash away any irritants. When the eye experiences irritation—whether from foreign particles, chemicals, or physical abrasion—the lacrimal glands are stimulated to increase tear production as a protective mechanism. This process helps to flush out irritants and provides a soothing effect to the surface of the eye.

In contrast, increased eyelid movement may help distribute tears but does not directly cause their production in response to irritation. Exposure to bright light can lead to tears as a response to photophobia (light sensitivity), but this is distinct from the reaction to debris or irritants. Similarly, a lack of moisture in the air can lead to dry eyes rather than increased tear production, as dry environments can have the opposite effect on tear secretion. Thus, the activation of the lacrimal glands is the most direct and relevant cause of tear production in response to irritation.