Iris: The colored ring of tissue behind the cornea that regulates the amount of light entering the eye by adjusting the size of the pupil. Lens: The transparent structure suspended behind the iris that helps to focus light on the retina; it primarly provides a fine-tuning adjustment to the primary focusing structure of the eye, which is the cornea. read more
Region at the back of the eye where the optic nerve meets the retina. It is the blind spot of the eye because it contains only nerve fibers, no rods or cones, and is thus insensitive to light. read more
The part of the eye that focuses light on to the retina. Structure: It is a clear piece of material in convex shape. It is behind the pupil. Function: It can change in thickness so that light can be focused onto the retina. read more