Eye anatomy, artwork. The eye is seen in cutaway format from the side. Structures shown include the lens (light blue, lower left), its attachment points, the iris, and the bulge of the cornea at the front of the eye. Several layers of the eyeball are shown, including the sclera (outer layer), the choroid, and the retina (innermost). Retinal capillaries (red and blue) are shown. The optic nerve (yellow) is at far right. External structures shown include muscles (red) that control the movement of the eyeball, and nerves (yellow) and more arteries (red) and veins (blue).