Water is a transparent and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen and two hydrogen atoms, that are connected by covalent bonds.Wikipedia
By now it should be clear that drinking water affects more than just your mouth and throat. A lack of water intake leads to dry, bloodshot eyes (again, think of that last pounding hangover). Without water in the body, your tear ducts dry up. If you’re thinking “So what if I can’t cry?”, realize that this could cause much more harm to your eyes, especially if you wear contacts on a daily basis.
1. Your Eyes Are Dry