The Evolution of Progressive Lenses

MedGadgets provides a re-fresher about progressive lenses: "In the past, producing these lenses was no easy feat. The traditional process required a semi-finished lens with a standard front. The prescription would be ground onto the back surface with a generator. Calculating the geometry to impart on the lens involves complicated mathematics." Eventually it offers an excellent description of today's digital, free-form progressive lenses. Read more.