Human Eye

The eye is an essential part of the human body. The human eye consists of many parts that interact and function to their purpose. The parts of the eyes are as follows: The resilient outer layer of the eye is called the sclera. Its purpose is to maintain the shape of the eye. The front sixth of this layer is clear and is known as the cornea. The muscles attached to sclera that prohibits us …

…being should be able to see when standing 20 feet away from an eye chart. If you have 20/20 vision, it means that when you stand 20 feet away from the chart you can see what the "normal" human being can see. (In metric, the standard is 6 meters and it's called 6/6 vision). In other words, if you have 20/20 vision your vision is "normal" -- a majority of people in the population can see what you see at 20 feet.