Peripheral vision is very important, because we need to sense motion or items out of the center of our focus without turning our eyes or head. This becomes vital when it comes to driving. If a driver can't use peripheral vision properly, he won't be able to sense sudden change in the surroundings. Accidents can happen for this.
When light enters retina, the sensor cells known as rods and cones which concentrate in the center of retina send signals to the brain through optical nerves. These cells scatter less in the peripheral area of the retina, so peripheral vision is not as clear as focus vision.
At first, I need to say that peripheral vision is a part of vision. In general, far peripheral vision, mid-peripheral vision and near-peripheral vision exists at the edges of the field of view, in the middle of the field of view and next to the center of gaze respectively. As we know, we get the images of a object by our imaging system. It receives the lights reflecting from the object by receptor cells and then transform them into chemical information. Finally, our brain can receive the image by translating the chemical information. Our receptor cells on the retina are assigned most at the center and lest at the edges. The two main cells, rod cells and cone cells help us to distinguish color and shape. The former is concentrated in the periphery to distinguish shape, while the latter is predominant at the center of the retina to differ color.
Yes, peripheral vision is so important to help us focus on something although it is not strong at the human eyes. The peripheral vision will help us see things around us. The peripheral environment will be seen by this vision. We need to protect such vision to make the whole health of the eyes. It is very important to keep the health of eyes.