Tests were done in the past that prove that deer can pick out the color red, using colored lights and a food reward as incentive to prove it. What that proves, I won't speculate.
As to the comment about a deers vison? The ability of a deer to see motion is literally astronomical. All three of their senses are.
It is their ability to interpret what they see, not the actual ability to see it, that is important to hunting conditions.
To assume a deer doesn't see you because you are wearing como is a mistake.. They see you, but without movement on your part, they don't interpret it as a danger, usually.
Deer are funny critters that are extremely aware of their surroundings. Any change in those surroundings sends up flags to them. If you was to go into the timber and find a well used deer trail, and lean a shovel against a tree near it, then get in a stand a ways off and watch... the next deer that comes down that trail (if it is within his normal territory) will probably instantly recognize that something is different and his guard will go straight up, and his tail will flare..
If you walk into your kitchen and see that someone has moved the table six inches from it's normal place, you may not understand exactly what is different, but you will be alert to the fact that something IS different. Deer are exactly the same.