Quote Originally Posted by the doors
isn't it just dehydration that makes them red.
Nah, the capillaries (tiny blood vessels) in your eyes dilate, or get bigger. It allows more blood flow to reach your eyes. And eye drops (like Visine) constrict your capillaries.

For the topic at hand, my eyes don't get red. I get sorta squinty and my eyes get really glassy.