Bipolar progressive power ophthalmic lenses are described, the constant power distance portion and reading portion regions of the progressive power surface being reduced to mathematical points and the surface astigmatism aberration is spread over a maximally large area of the lens. The points are the poles of a bipolar system of isopower contours and the entire progressive surface is swept out by the curve of intersection formed between a moving sphere of variable radius and a comoving circular cylinder of variable diameter with the dimensions of relative positions of intersecting sphere and cylinder chosen so as to produce a gently curving surface to provide a smooth optical effect.
展开▼
