Purpose of drainage pore in a dog's eye?

I'm doing a project on the sight of a dog and in a diagram i found online - http://www.wuffybrother-music.webs.com/d鈥?/a>


it shows a drainage pore on the front of the eye. I was just wondering what the purpose of this drainage pore is.





Thanks,


WuffybrotherPurpose of drainage pore in a dog's eye?
There are several drainage points in a dogs eye. Some are there to drain the aqueous fluid formed by the eye these are the small bumps on the upper eyelid. This fluid needs to be replaced. There is also one to drain the liquid made by the lacrimal glad moves across the eye into that tube. This tube leads to the nose where it drains. Often ophthalmologist will check the function of the eye by putting fluorescent drops in the eye and see with a black light if it is coming down the nose. If this tube is blocked the eye will have increased pressure.