Eye lens. Coloured scanning electron micrograph (SEM) of a freeze-fractured lens (crystalline lens) of an eye, showing the cuboidal epithelium cells (layers). The lens, which is found at the front of the eye, focuses light onto the light- sensitive cells in the retina at the back of the eye. Cuboidal epithelium is found at the front of the lens. Magnification: x150 when printed 10 centimetres wide.