The first spectacles, designed to correct farsightedness, bore glass magnifiers that ... he discovered that plano-convex and plano-concave lenses worked best—that is, lenses with a plane on ...

Technically, the glasses have a distance sensor embedded ... The design is small, light, can produce plano-convex or plano-concave lenses, and can do so quickly (within 15 ms) and with low ...