Phototransduction cascade

Phototransduction is the process by which your eyes convert light into electrical signals for your brain to interpret as images. In the eye's retina, specialized cells called rods and cones detect light. When light hits these cells, it causes a change in a molecule called opsin coupled with a pigment called retinal. This change initiates a cascade of biochemical reactions that ultimately reduce the level of a signaling molecule called cGMP. Lower cGMP levels cause ion channels to close, hyperpolarizing the cell. This electrical change is transmitted to the brain via the optic nerve, allowing you to perceive visual information from the light entering your eye.