In order for a pair of eyeglasses to be perfect for you, the optometrist or ophthalmologist must measure a few things truly vital for your eyes, and I name them now even if they are particularly technical terms,Diopters, Pupilary distance,Pupil height,Left-right eye asymmetry. It takes all this for tailoring the eyeglasses to your eyes and only for your eyes! If any of these characteristics is wrong, you will not have a clear vision. Using such wrong reading eyeglasses, these mean headaches, blurry vision or tearing if you use them for a longer time, even half hour. The worst part is that your eyes will get tired more quickly than with prescription eyeglasses. So your diopters will grow faster in time.