The eyeball is divided into 2 segments: the anterior segment in front of the lens and the posterior segment behind the lens. The anterior segment has 2 subdivisions: The anterior chamber and the posterior chamber. Let’s remove the cornea of the eye, and look behind the cornea into the anterior chamber. You’ll notice a clear watery fluid leaking out of the incision. This fluid is the aqueous humor which fills the anterior segment. The anterior chamber is the space between the cornea and the iris. The iris is the colored part of the eye. It’s a muscular structure that controls the size of the pupil. Let’s put a piece of white adipose tissue behind the iris, so we can better see the shape of the iris, and the opening in the middle, which is called the pupil. Light passes through the pupil to the lens. The pupil leads into the posterior chamber, which is the space behind the iris,