Here are some of the main reasons we have tears:
- Tears protect the eye. Whilst we hate to state the obvious, they keep your eyes wet. But why would you want wet eyes? First, they're more comfortable that way - especially if you expect to be able to blink. Second, your corneas are built to expect a wet surface and they'd get really unhappy without it. In fact, if your eyes get too dry you will develop erosions, abrasions and even ulcers and scarring on your eyes. Some of you have experienced that and you know exactly how unpleasant it is.
- Tears provide all kinds of proteins and nutrients for the eye. You could say they nourish the eye. That is a Good Thing. You want as much of that nourishment as you can get.
- Tears refract light. That's a fancy way of saying that they do the same kind of thing that your glasses do - they help bend the light on its way to the back of your eye (the retina) so that you can see nice and sharp images. So, if you don't have the tears you need, you might not be seeing nice, sharp images... and vice versa.
Learn more about The Components of a Healthy Tear Film.