What does a dog actually see, how does it perceive the world around it? There are a large number of differences in the structure of the visual apparatus of a dog and a person, and, therefore, in perception too.
Dog eye structure
A dog's organ of vision includes the eyeball and auxiliary organs. The eyeball communicates with the brain by the optic nerve.
The eyeball consists of the retina, fibrous and vascular membranes. The fibrous (outer) sheath includes the sclera and cornea. The sclera is the attachment point for the tendons of the eye muscles. The cornea is responsible for conducting light to the retina.
In the choroid (middle) are the pupil, the ciliary body and the choroid itself, due to which the retina is nourished. In the retina, there are photoreceptor nerve cells - rods and cones, which carry out light and color perception, respectively.
Accommodation - the ability of the eye to change the focal length - is the responsibility of the lens located in the cavity of the eyeball.
Eye work
Light penetrates the pupil and focuses on the retina using the cornea and lens. The amount of light entering the eye is regulated by the iris by changing the size of the pupil. The retina perceives light and, through the visual channel, transmits information to the animal's brain in the form of a nerve impulse.
The lacrimal glands prevent the cornea from drying out. The third eyelid cleans the eye from dirt.
Features of dog vision
Based on the structural features of the organs of vision and the work of the eyes of dogs, the following features of visual perception can be distinguished.
Dogs have color vision. There are 2 types of cones in the retina. These are the receptors responsible for the yellow-green and blue-blue colors. This means that many color shades, different to humans, are seen by a dog in a similar way.
Dogs do not have receptors for red color, a similar color perception is found in people with color blindness.
Visual acuity in dogs is significantly lower than in humans. The indicators of vision are approximately + 0.5 diopters. The organs of vision of dogs are able to distinguish more than 35 shades of gray, due to the large number of rods, which have a high light sensitivity in low light conditions.
Dogs are able to perceive a moving object from a distance of up to 900 meters, a stationary one - only from 600 meters. The latitude of the dog's peripheral vision depends on the characteristics of the breed and is approximately 250 degrees.
If we imagine the situation that a dog checks eyesight with an ophthalmologist according to the Sivtsev table, a healthy animal would distinguish only the third line, while a person - the tenth.
Analysis of the structure of the visual organs of the dog and the peculiarities of visual perception shows that dogs perceive the world around them differently than humans. Although the dog's eye is inferior to human vision in the ability to distinguish a rich palette of colors, dogs respond better to moving objects, orient themselves in the dark and have wider peripheral vision.
