Diagram showing the structure of the eye. Most of the light in the visual spectrum first passes through the cornea (clear front layer of the eye) and then the pupil. This light is focussed by the lens together with the cornea, onto the retina at the back of the eye. In the retina, photoreceptor cells called rods and cones convert the light into electrical signals. These signals travels to the ganglia and through the optic nerve to the visual cortex in the brain. The visual cortex is the area of the cerebral cortex that receives and processes visual information. Blue light is captured through the ganglia with melanopsin (ipRCG) and the signal goes to the optical nerve. Some of the singal from blue light is processed by the visual areas of the brain and some are processed by non-visual areas.