What Is The Lens? The lens is a transparent tissue which helps the eye to focus light and images on the back part of the eye. This is the part of the eye which can develop a cataract. In normal health, the lens is held in place behind the iris and pupil by multiple zonular fibers. In the office, we will compare the lens and its fibers to a trampoline and its springs. These fibers can become damaged for a few reasons, and instability of the lens can lead to a subluxation or co