What's the purpose of the Lacrimal punctum?

I was looking in the mirror to find a piece of crud in my eye when I noticed a spot on the inner part of my inner eyelid. When I discovered that my other eyelid had a matching spot, I looked up a diagram of the eye and discovered that this was the inferior lacrimal punctum, which apparently allows tears to drain into the inner nose. Since I’ve discovered a part of me I didn’t know I had, now I’m very interested in it.

What’s the purpose of having a duct in our eyelids to drain tears into our nose?

The eye produces the tear film continuously. Would we otherwise be constantly leaking tears down our faces?

That’s exactly it. The lacrimal punctum is the low point drain of the eye. It’s like a storm sewer. If, for examply, the lacrimal sac is blocked by something, you’ll have constant tearing, and the sac itself will become inflamed and possibly infect, and you’ll end up having a dacryocystorhinostomy. I could start a “Ask the person who has had a dacrycystorhinostomy” thread, but it’s not that interesting.

Sorry if I made you recall some bad memories.

I’m guessing the top ducts would work through some kind of capillary action. I’m guessing.

Interestingly enough, some people with dry eye benefit from having small plugs of silicon placed into their puncta. This prevents the tears from draining (or slows down the rate at which they drain,) thereby providing more moisture to the cornea.

For people with allergies, does this “drain” become clogged? This would explain why their eyes become so teary? (My wife’s eyes drip a lot in-step with allergies.) Or, maybe it overwhelms its drainage capacity, I WAG?