Theoretically, reading glasses is for looking the object nearby and the eyeglasses used to look at computer is for looking middle distance. There are several solutions to these differences, besides simply buying separate reading and computer glasses. One is to have special bifocals, with one part of the lens dedicated to reading the printed page and the other part customized for computer screen use. This isn't an ideal situation for all users as, unlike reading a page from top to bottom, it's more likely the eye will need to dart about when using a screen, which can require head movement when using bifocals. A more sophisticated solution is progressive addition lenses that, rather than simply being split into two lens strengths, gradually increase power moving from the top of the lens to the bottom. This allows easier adjustment to different types of visual material.