Progressive reading and intermediate distance lens defined by employment of a zernike expansion

Abstract

There is provided a lens that includes a surface having a continuous monotonic change of power through (a) a first zone for reading at a distance of about 35 centimeters to about 45 centimeters from said lens through (b) a second zone for viewing at near and intermediate distances from about 45 centimeters to about four meters from said lens. The second zone includes a corridor having a length of greater than or equal to about 16 millimeters and a width of greater than or equal to about 6 millimeters along said length. The lens has surface astigmatism less than or equal to about 0.5 diopter within said corridor, and is a progressive addition lens.

Dependencies are inferred from the claim text.