Princeton's WordNet(0.00 / 0 votes)Rate this definition: 1  shimmer, play(verb) a weak and tremulous light. 2  shimmer(verb) shine with a weak or fitful light. 3  shimmer(verb) give off a shimmering reflection, as of silk.
Cats, like humans, have both rods and cones in the retina. Rods are the receptors that the eye uses for night time viewing and sudden movement. Cones are used during the daytime, and process color information. Cats have more rods than cones, as compared with humans, making cat night vision superior to humans.
How the eye perceives color. To make things more complicated, no two eyes see things the same. The eye perceives color through the rods and cones. The color we see is a wavelength of light that our eyes interpret using these rods and cones. The rods see black and white and the cones perceive colors. Shade selection is best done with light most suited for our eyes.