Progressive lenses are normally divided into three parts: distance (which is the upper portion of the lens), intermediate (the middle part,typically used for computer) and reading (the lowest portion of the lens). The power are graduated from the top to bottom part of the lens therefore giving a vertically curve area which enable the wearer to see clearly in all distances. The sides of the lenses give a bit of a blurry part which is eliminated once the lenses are cut and fitted to the frame.