"The eyeball is like a basketball or a tire, and in this way it has a pressure. Fluid (called aqueous humor) is made inside the back portion of the eye called the "ciliary body". This fluid is created inside the eye, and nourishes the eye. It slowly travels from the back part of the eye to the front of the eye to an area called "the angle" or "trabecular meshwork", where it then exits the eye."