Epiphora, also known as watery eyes when exposed to wind, has both physiological and pathological causes.
There are three main physiological causes. First, the amount of tears secreted by the lacrimal glands exceeds the drainage capacity of the tear ducts, causing them to overflow. Crying is one example.
Second, the lacrimal glands are stimulated by cold air or wind, causing a reflexive increase in tear secretion.
Meanwhile, the lacrimal puncta and canaliculi contract spasmodically when stimulated by the cold, reducing the amount of tears they can absorb. This excess fluid then flows out onto the surface of the eye, forming tears.
Third is eyelid laxity.
This is most common in middle-aged and elderly people. Their tear ducts are unobstructed, but due to the sagging of the eyelid skin and decreased strength of the surrounding eye muscles, the siphoning action for tear drainage is reduced, leading to poor drainage and watery eyes.
