Eye specialists recommend that we read sitting at a table and having a certain angle of view inclination with respect to a book and a certain distance to a page. There is a chance that such disciplined people exist, but we prefer reading ensconced in a soft armchair or sofa, preferably with a parcel of chocolates… And at the same time we would like to preserve our eyesight, especially if our eyes are strained as a result of such reading method.
For this purpose, special curved glasses have been invented. They employ the periscope principle. You may relax your neck and look at the ceiling and the curved glasses will do everything instead of you – they will change the angle of view so that you see the page. The same principle of operation may be used for watching television in any posture, even when a TV set is behind you.
For reading convenience, the glasses as if move the book image to a different dimension – from vertical to horizontal.

Information source: Hammacher Schlemmer