The lens of the eye is the only formation of the body that does not have blood vessels and feeds only through the eye fluid.
90 percent of all human labor activity takes place with the obligatory participation of the eye. The work of the eyes continues on average for 15-18 hours a day. 87 percent of all impressions a person receives from the outside world are visual impressions.
The ability to distinguish colors does not appear immediately in a person. The eye must train for a long time to learn to see colors. The world is presented to the newborn as a monotonous gray photograph. Only at 6-7 months does the child begin to distinguish colors. This ability is developed by hanging in front of him and showing him colorful toys.
A person in the dark can see the flame of a candle at a distance of over a kilometer. Human visual acuity at night is the same as that of an owl, but four times worse than that of a cat. But during the day, a cat's eyesight is five times weaker than that of a person.