Hello, my name isXXXXX and I have over 20 years of experience as a veterinarian. I'd like to help with your questions about mice and their ability to see including seeing color, fear of people and tendency to run along walls.
Mice are nocturnal animals and in low light being able to see color isn't a desirable trait, as colors aren't easily distinguished in low light. As such mice never developed the ability to see colors well and are considered red/green color blind. In general their vision is poor, they can see shapes and motion but do not have good, focused, fine vision. Their senses of hearing, smell and taste are so good, and much more useful in low light, that their poor vision isn't usually a detriment to them. It's enough that they can see the motion of a predator coming and they depend upon their ears and sense of smell to localize food and predators from afar.
Many house mice become habituated to the smells, sounds and sight of people and no longer find them intimidating or necessarily as predators. Because of that they are quite bold around people, much more so then others that they still perceive as a threat such as dogs or cats, which they quickly run from. The reward of easy food in a home makes them bold as well and they are willing to risk being seen by people to eat well.
In the wild mice tend to stick to covered areas or along paths to hide from owls and other predators and quickly get back into cover if they appear. House mice, habituated to people, become less fearful and thus are much more bold and will forget their habits of hiding in exchange for the ability to quickly get to food.
I hope that this information is what you needed to know, please let me know if you have any further questions.