The globe-shaped eye is located within the bone called orbit, and protected by eyelids. Outside is white sclera and there is a transparent layer of cornea. Below the cornea is the iris, which gives the color of the eye. In the middle of the iris there is a pupil whose width changes according to the amount of light. Behind the iris is the lens of the eye (lens). This structure is transparent and disk shaped. Below the sclera is the vascular layer of the eye (uvea) and the underlying layer (retina) that allows it to be seen underneath. Visual stimuli are transmitted from the retina through the optic nerve (optic nerve) to the brain.