Patent US5000559 - Ophthalmic lenses having progressively variable refracting power

Ophthalmic lenses having progressively variable refracting power are designed to have good aberrational balance, a wide field of view, large clear vision areas, and minimal image distortion and shift. Aberration density is reduced in a progressively variable refracting power area in a side portion of...http://www.google.se/patents/US5000559?utm_source=gb-gplus-sharePatent US5000559 - Ophthalmic lenses having progressively variable refracting power $Patent US5000559 - Ophthalmic lenses having progressively variable refracting power$