Patent ID: 6726323
Filing Date: 2004-04-27
Classification: G02C

Abstract:
A contact lens comprising:a central optical zone including a front optical zone and a back optical zone; and a peripheral zone surrounding the optical zone and including a front peripheral zone and a back peripheral zone, wherein said contact lens is provided with a dioptric power P ranging from âˆ’10 to 0 diopters (âˆ’10&lE;P&lE;0), wherein said front optical zone and said front peripheral zone join together at a front junction, and said back optical zone and said back peripheral zone join together at a back junction that is located outward of said front junction in a diametric direction of said contact lens orthogonal to a center axis of said contact lens, and wherein said contact lens has a central lens thickness TC ranging from 0.03 to 0.50 mm as measured along said center axis thereof, a front junction lens thickness TFJ of not less than 0.05 mm as measured at said front junction, and a back-junction lens thickness TBJ as measured at said back junction, said back-junction lens thickness TBJ is determined depending upon said dioptric power P so as to satisfy a following expression: &Sgr;(AiÂ·10âˆ’iÂ·Pi)&lE;TBJ/TFJ&lE;&Sgr;(BiÂ·10âˆ’iÂ·Pi) where, A0=+1.2382 A1=âˆ’0.1741 A2=âˆ’1.4711 A3=âˆ’0.9355 B0=+1.4699 B1=âˆ’0.2523 B2=âˆ’1.9897 B3=âˆ’1.2603.