The Eyes Have It!. Light, Lens, Action!. How the Eye Works.
Rods and cones are special cells that process light.
Rods and cones are extremely small. In fact, there are about 120 million rods and 7 million cones in each eye!
Rods help us see black and white and shades of grey.
Cones help us see color. You have three kinds of cones are - red, green, and blue. These cones work together to help us see millions of colors.
There are the six small muscles that move each eye from side to side, up and down and on the slant. When these muscles don't work together, it can affect vision. One condition that can arise when these muscles don't work together is “lazy eye”, a condition that affects about 5% of children and arises when the eye muscles don't work together properly. This leads to "lazy eye," in which one eye takes over all the vision duties.
A defining characteristic of these tiny muscles is that they are nearly always moving, even during sleep. In fact, even when "staring" at a fixed object, the eyes keep moving over the image. Although these muscles are very small, they use a lot of energy because they are always on the go.
Not all people have perfect vision.
People who can see things up close, but not far away are considered to be nearsighted. This happens when the light entering the eye focuses on a point in front of the retina.
Whether a person is nearsighted or farsighted, glasses or contacts help that person to see things much more clearly!
VISUAL ACUITY: A person who has sufficient visual acuity should see the number twelve in the circle on the left whether or not they have normal color vision. I
COLOR BLINDNESS: A person with normal color vision sees a number seven in the circle on the left. Those who are color blind usually do not see any number at all.
RED-GREEN COLORBLINDNESS: People with red-green color blindness see either a three or nothing at all. Those with normal color vision see an 8.
the Illusion that the picture is moving.