Each time we blink, we secrete a layer of tears onto the front of the eyes. A healthy, ‘normal’ tear film will cover the front of the eyes for about 10 seconds until the liquid evaporates into the air, or drains into the nose and we feel the need to blink again.
If the composition of the tears becomes altered due to hormonal changes, general health conditions or medicines, environmental conditions or changes to the structure of the eyes, the tears may well evaporate much quicker than this. Without a covering of tears on the front of the eyes, small nerves are exposed to the cold, wind and general environment and the eye quickly becomes irritable and uncomfortable.
When our brain becomes aware that the eyes are uncomfortable, this can trigger the release of extra tears, known as reflex tearing. The composition of these tears is generally thinner, more watery and they are usually secreted in a higher volume than normal tear flow. This is why reflex tears often spill out of the corners of the eyes and run down our cheeks. This can be very annoying, especially when wearing makeup or if the skin around the eyes is sensitive.
So, ultimately, eyes generally water due to an issue of dryness or poor-quality tear film in the first instance. The best way of reducing watery eyes is to improve the tear film quality.