Apparatus for injection molding thermoplastic lenses, such as prescription eyeglass lenses, in a single injection molding operation into a finished single vision or multifocal blank which does not require additional molding or polishing. Movable optical inserts (dies) are forced apart by injected polycarbonate,...http://www.google.com/patents/US4008031?utm_source=gb-gplus-sharePatent US4008031 - Apparatus for injection molding lenses
