Let’s skip, all the technical mumbo-jumbo. It should be enough to say that deer don’t see the world the same ay we do. (See the image above) All deer are red/green colorblind. This means a deer can tell blue from red, but not green from red or orange from red. Deer actually see blue, violet, and indigo extremely well. This is why it is best not to wear those colors if you hope to remain unseen. Many hunters worry about wearing blaze orange, believing it makes them more visible to the deer. The truth is deer can hardly see that shade at all.
Keep in mind is that deer see the ultraviolet (UV) spectrum much better than we do. Ultraviolet is the shortest wavelength of light and is nearly invisible to humans. Our eyes filter out these wavelengths, allowing us to see better during the day and protecting our eyes. Because a deer lacks this UV filter, he’s prevented from seeing detail during daylight, but his night vision is enhanced. Don’t bother trying to sneak up on deer under the cover of darkness, it just doesn’t work. With any kind of ambient light at all, deer can see as well at night as you can during the day
A deer’s vision is geared primarily to detect motion. Even the slightest movement seems to be noticed. To top that off, a deer’s eyes are on the side of its head, giving it over a 310 degree field of view. Only when we can’t see the deer’s eyes can our movements go unnoticed. So if you must move, move so slowly the deer does not notice. The key to eluding a deer’s eyesight is lack of noticeable movement. If you hope to see the deer before he sees you, you must either be very still, or move slow enough that the deer does not detect motion.