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Rat Vision
Compared to the 20/20 vision that an average human being with healthy eyesight has, a rat's normal vision falls in the vicinity of 20/600 -- making the rat's world a very blurry one. Based on the location of their eyes, rats have panoramic vision as opposed to humans' binocular vision.
Human and rat retinas both have rods and cones. Rods detect tones and are used at night, while cones detect colors. Although rats do have cones, they use and rely upon rods as the primary photoreceptor.
Rat Color Perception
Rats do perceive color, but compared to the trichromatic vision humans have, theirs is limited, only consisting of a dichromatic system due to the one less cone they have in their retinas. Rats can't see red, but they can distinguish the differences among ultraviolets, greens and blues. The blurry vision of these colors comes second to rat's ability to see in black and white -- thanks to rods.
Pigmented Rat vs. Albino Rat
Albino rats do not have the same vision as pigmented rats do. Their eyes appear pink or red because of the lack of melanin. This lack makes light scatter inside the eye, so while pigmented rats have poor vision, their albino counterparts have it much worse. They can be extremely visually impaired to the point of blindness.
Colorblindness Myth
Rats are mammals and with the exception of a few species -- such as squirrels, primates and humans -- mammals generally lack color vision. For a long time, rats were thought to be completely colorblind as well, but recently scientists have shown this is not the case. Nevertheless, more studies are being made to find out whether color vision means anything to rats due to its poor performance, or whether it serves as a left-over evolutionary trait.