Why is it important to have exact standards of measurement

The results of huy's eye exam show that he is nearsighted. which explanation should huy expect to hear? "you need convex lenses to shorten the distance that light takes to focus in your eyes." "you need concave lenses to shorten the distance that light takes to focus in your eyes." "you need convex lenses to lengthen the distance that light takes to focus in your eyes." "you need concave lenses to lengthen the distance that light takes to focus in your eyes."