Schools, television, and movies all use this knowledge effectively to present ideas to their audiences. Vision is most commonly described in terms of an acuity measure, or the best a person can see. Vision can be hampered in a number of ways.
Refractive errors can create distortions.
Nearsightedness Farsightedness Astigmatism M uscle balance problems, or crossed eyes, can prevent the two eyes from lining up to see the same thing. When they work together to produce one image, this is called binocular vision. B inocular vision lets us judge the size and distance of an object from simple observation. This is known as depth perception, an important factor for good mobility. An adult may see two images, or double vision, but a child who is learning to use vision will begin to see only the better image.