Patent ID: 6213603
Filing Date: 2001-04-10
Classification: G02C

Abstract:
A progressive ophthalmic lens comprising:at least one distant vision zone, the power of which is suitable for distant viewing;at least one near vision zone, the power of which is suitable for near viewing; andat least one progression zone, in which the power varies continuously from the power of the distant vision zone to the power of the near vision zone along a principal line, at least one surface of the ophthalmic lens contributing to the power variation;wherein a surface astigmatism of the at least one surface of the ophthalmic lens contributing to the power variation along at least one horizontal intersection, represented by an intersection of the ophthalmic lens and a horizontal plane where x is variable and y is constant, has a local maximum value which is defined by the formulas.differential.(.DELTA.S)/.differential.x=0;.differential..sup.2 (.DELTA.S)/.differential.x.sup.2 <0;and which is located at a distance in the x direction of not more than 4 mm from said principal line, and at least one local minimum value which is defined by the formulas.differential.(.DELTA.S)/.differential.x=0;.differential..sup.2 (.DELTA.S)/.differential.x.sup.2 >0;and which does not lie on said principal line and is located at a greater distance from said principal line than the location of said local maximum value.