Abstract: An ophthalmic lens element having a first surface and an atoroidal or generally aspheric second surface. The second surface is described by a symmetric polynomial whose coefficients have been chosen to minimize a merit function constructed of the sum of a particular optical aberration over substantially the entire surface thereof.

Abstract: A progressive ophthalmic lens element having a front surface that includes an upper viewing zone having a surface power suitable for distance vision, a lower viewing zone having a surface power suitable for near vision, and a corridor of relatively low astigmatism connecting the upper and lower viewing zones, the corridor being a part of an intermediate viewing zone having a surface power varying from that of the upper viewing zone to that of the lower viewing zone. The progressive ophthalmic lens element also has a back surface. The invention is then characterized by the front surface including at least one correction to improve optical performance of the lens element by at least partially compensating for a cylinder correction applied to, or to be applied to, the backsurface.

Abstract: A progressive ophthalmic lens element including a lens surface having upper viewing zone providing good optical quality at a predetermined low surface power over a large area of vision; said predetermined power being determined by the viewer's distance prescription (R.sub.x) the horizontal fitting position normally being determined by the inter pupillary distance of the wearer, and the vertical fitting position normally being determined by the vertical frame midpoint; a lower viewing zone of higher surface power providing an enhanced range of vision for intermediate or lesser viewing distances; and a corridor of relatively low astigmatism extending therebetween; wherein the contours of mean surface power and/or surface astigmatism within the lower viewing zone, upper viewing zone and corridor are generally symmetric about a vertical lens meridian.