As the diopter increases, you shorten the focal length where you see the magnified object clearly. As the diopter increases the lens becomes thicker and the curvature greater. Higher diopter lenses have greater magnification power. The field of view is the size of the area that is seen through the magnifier. The field of view decreases as the power increases.
More powerful lenses make small details look big, but less of the total object is visible.
There is a trade-off for the viewer who must decide between the size of the field of view, and the amount of magnification . The distance that a magnifier can be moved from an object, and still have the object in focus, is the depth of field. With depth of field, the higher the power, the shorter the depth of field. Proper lighting is equally as important as magnification in achieving a good viewing situation. Increasing light levels results in better vision.