SPECTACLE LENSES HAVING AN INSIDE-OUT CONICOIDAL FRONT SURFACE

摘要

Plus and minus power ophthalmic spectacle lenses for the correction of distance vision incorporating a convex aspherical front surface are provided. The front surface (14') of the invention is described mathematically as an inside-out conicoid. The inside-out conicoidal surface (14'), when used in conjunction with a concave spherical or toroidal back surface (12'), provides a lens having improved off-axis optical performance and reduced thickness and flatness characteristics relative to prior art lenses of the same back vertex power and refractive index.