These wonderful doggie facts come from this website

1. It is a myth that dogs are color blind. They can actually see in color, just not as vividly as humans. It is akin to our vision at dusk.
2. Dogs DO have better low-light vision than humans because of a special light-reflecting layer behind their retinas
3. A German Shepherd guide dog led her blind companion the entire 2100 mile Applachian Trail