The primary difference in feline versus human vision has to do with the distribution of structures in the eyes called rods and cones. Cats are hunters. They need to be able to identify their prey at a distance, and on the move by shape. Nature has thus equipped them with more rod cells, which allows for shape perception and motion detection.

In comparison, however, cats have fewer cone cells than humans, so they have a diminished ability to distinguish colors. They are not color blind, but they cannot make out shades of red well, which translate into gradations of gray.

Where cats do excel over us in every way, however, is in their ability to see in low light. They cannot see in complete darkness any more than we can, but those luminescent eyes actually betray the presence of a specialized layer of cells behind the retina called the tapetum lucidum.

This layer casts the image back on the retina a second time allowing for a form of “night vision.” The cat sees with a decreased degree of focus and even more monochromatically, a fact offset by his superior ability to track motion. The result is eyesight uniquely adapted for the life of a small, crepuscular hunter. In the same light, humans would be tripping all over themselves.