Google it maybe pay attention next time
It is use by Eye Care Professionals To check the eyesight of a person.
If u would have visited a eye care centre u would have noticed a chart like this--
If a person can see all the letters from a distance his eyesight is Perfect.If that person misses a letter or a line from the grid eye treatment or spectacles are given to the person for improving their eyesight
1. Eat right. Egg, spinach, Dark chocolate, milk.
2. Include lean protein in your diet<em>, beef, pork, egg whites.</em>