Once they squint their eyes, they could use the peripheral vision to help them see things better. However this is the very bad habit of using your eyes which will make you become the squint eyes. You'd better see things in the right direction. If you don't see it clearly, you need to check whether you have the problem at the eyes.
Squint eyes, also known as crossed-eye, in medically it is called strabismus. It is a condition that each of eyes does not focus on the same direction. In fact, no exact reason can explain this phenomenon. Our eyes are controlled by six muscles. Squint eye may due to muscles incongruous working. However, there are other reasons. People with poor vision may squint their eyes too. So it depends.
This is because that when people squint their eyes their eyes adjust by themselves to overcome the optical defect in their vision. When people are seeing things in a very far distance, they may not see the things very clearly because the light given out by the things in the far distance can not form a distinct image on the retina, which is partly due to the strong illumiantion around. But if the people squint their eyes, the eye will be like a pair of pinhole glasses to avoid the surrounding mussy lights entering into the eyes, so that the central lights from the distant things can directly form a distinct image on the retina. In spite of the fact that squinting eyes can make people see clearly, it is not a good habit to usually squint eyes because it will transform the shape of eyes as well as worsening the eyesight.