To sharpen the object you look, you have to fix it through a very small area. To do this, close your fist and place it on the bridge of the nose. Narrowing his eyes, look at the object through the small hole that forms a fist. Another technique is to pinch the thumb and forefinger of each hand, and bring them together so that the tips of your four fingers form a diamond. Similarly, look at the object through that tiny frame. You will discover that the lines are more accurate.
Why this trick she can see better?
This simple process has a mechanical effect on vision. When we look at a scene, the retina reflects light. The images are thus sent by the optic nerve to the brain, which analyzes. Now, with eyes wide open, the light will be printed in the eye in large quantities. Retinal fatigue and, with time, the eye has more and more difficulty processing the images, which appear slightly blurred. Squinting and reducing the observed area, you Regulate the flow of light. The eye focuses on a small area, which is so sharp. This operation does not damage the eyes. However, if you are forced to repeat it regularly, it is probably that you need glasses: it is time to consult an optometrist!