The principle of the universal spectacles is based on the discovery of Alvarez, an American who, in 1968, won the Nobel Prize in the field of high-energy Physics. The lens is composed of two moveable parts with a flat surface facing each other and “saddle form“ outer surfaces (see fig. 1). Alvarez mathematically demonstrated in 1964 that the refractive power of the combined lenses vary proportionally with the amount of relative movement of the lens parts.

Fig.1 The Alvarez-principle	Fig.2 Luis W. Alvarez (Nobelprize, 1968)

During the 60’s it was not possible to fabricate this kind of lens that could match the theoretical specification with good accuracy. Today advanced optical computational technique and computer-controlled lens-polishing techniques are available.

      

The principle