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.
Special cells called Rods and Cones are used to process light, in a human eye, their number is estimated to be 5-7 million Cones and 110-130 million Rods. Cones are found mainly in the central area of the Retina (Fovea), while Rods are found in the Peripheral Retina. The Photoreceptors respond to light, it causes the activation and consequent breakdown of a photo-sensitive pigment, bound in large quantities to the membranes of the outer segment.