-Keywords: Pupil, lens, iris, retina, optical nerve
-Picture/video of a cows eye dissection
-Why do they have night vision?
Your Retina changes the light into a nerve signal. The nerve signal travels along the optic nerve to your brain. Your brain decodes the light and decides what to do with the visual information. Your Retina can be damaged by too much light. In bright light, your pupil becomes smaller to keep out some light.
Behind the retina is a layer of shiny, blue-green stuff called the tapetum. Tapetum is a reflective layer of the choroid in the eyes of many animals, causing them to shine in the dark. This layer assists night vision by reflecting light back through the retina. Humans don't have a tapetum, but cats, cows, and other animals do. A cat's eyes shine in the headlights of a car because of the tapetum.