
Owners of dogs and cats very often wonder how well their pet sees. Assessment of vision is reduced to an objective examination of the animal and observation of their behavior. Visual acuity is the ability of the eye to clearly distinguish between objects near and far. Dogs visual acuity is 20-40% of visual acuity of human …
In humans, visual acuity is determined by using the subjective method with vision charts, while in animals the acuity is determined by examining the eye’s background.
Dogs and cats have binocular vision, which means that they are viewing with both eyes simultaneously. Vision field is an area that our view covers when looking in one direction. Dogs have laterally placed eyes and their visual field is 240°, in cats it is 200° while in humans 180°.
Until recently it was believed that dogs and cats only see black and white, but recent studies show that animals still see some color. The possibility of color perception is regulated with the existence of photoreceptors in the retina. Conduct tests have shown that dogs can easily distinguish red from blue, but they are confused with the difference between green and red. The animals recognize objects by relying on contrast and motion. Dogs and cats are much more sensitive to light intensity than men, because they have a special layer of choroid that reflects the light beam, called the tapetum lucidum.
It allows animals to have good vision in dark. The tapetum’s mirror effect can be seen as a fluorescence reflection. All these functions of the eye must be developed in the brain to create the proper image.
Picture 1: Human vision
Picture 2: Dog’s vision