1. Eyeshine. At night, when caught in the headlights of a car, a camera’s flash, or other lights, cats’ eyes glow with a bright green reflection. This is due to an iridescent, light-reflecting layer of tissue called the tapetum lucidum, which is behind the retina. This structure lets cats reflect light back through their eyes and enhances their night vision. Other species, such as cows, dogs, and ferrets, share the trait.
2. Cone and rod cells. Compared to humans, cats have a proportionately lower number of cone cells and a higher number of rod cells in their retinas. Cone cells handle day vision and color discrimination. Rod cells are responsible for night vision and distinguishing shades of gray and brightness.
3. Limited color. Some sources believe cats, like dogs, only have two pigments in their retinal cells, while others believe they have three, allowing them to distinguish among red, blue, and yellow.
4. Nearsightedness. A study of 98 healthy normal domestic cats, published in the American Journal of Veterinary Research, found that domestic shorthair cats were significantly more likely to be nearsighted than longhair- or medium-hair cats.
5. Wider field. Cats are believed to have greater peripheral vision than humans at about 200 degrees versus the 180 degrees humans enjoy. However, a cat’s visual acuity (sharpness) is thought to range from 20/50 to 20/200.That means what a person can see in detail at 50 feet or even up to 200 feet, cats probably can see well only at 20 feet.