Draw a slightly oval circle that will serve as the outline of the eye. On the middle left side of the circle draw a smaller half circle whose flat end touches the circle previously drawn. The side bulging out to the left represents the cornea, a transparent disk of tissue where light enters the eye. Inside this half circle will represent the aqueous humor.
Further inside the first circle draw a thin oval the same length as the aqueous humor region, but make sure it does not touch the half circle. This is the lens, another transparent structure, according to Dee Silvethorn's "Human Physiology." The space between the aqueous humor and the lens is the iris, which gives the eye color. Leave an empty circle in the middle of the iris to represent the pupil, which changes the amount of light that enters the eye.
Label the area of the inside of the rest of the first circle the vitreous chamber. This gelatinous substance helps maintain the shape of the eyeball.
Next comes the fovea, the region which gives the sharpest vision. It is located in the vitreous chamber near the back and is depicted as a small dark circle.
Directly behind the fovea is the optic disk region where there the optic nerve and blood vessels start to leave the eye. There are no light sensitive rods or cones in this area, which is why the optic disk is termed the blind spot. The optic disk region is located on the middle of the right side of the first circle and is even with the cornea, creating the focal plane.
Label the bottom inner portion near the border of the first circle the retina; this layer contains rods and cones that are sensitive to light, called photoreceptors. Label the first circle outline as the sclera. This connective tissue helps connect the eye to the muscles which hold the organ in place.