Patent ID: 11886047
Assignee: HOYA LENS THAILAND LTD.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for designing, by means of a computer, a progressive addition lens comprising a distance vision region, a near vision region, and an intermediate vision region, wherein a power gradually changes between the distance vision region and the near vision region, and wherein the progressive addition lens is based on prescription data, the method comprising:
determining a transmission astigmatic performance parameter corresponding to a sum of a prescribed astigmatism included in the prescription data and a predetermined amount of extra astigmatism; and
determining lens surface data corresponding to the determined transmission astigmatic performance parameter,
wherein the amount of extra astigmatism is added in the intermediate vision region along a meridian so that an amount of vertical power is different from an amount of horizontal power along the meridian, the meridian being a meridian line of the lens along which a spherical power increases along a direction towards the bottom of the progressive addition lens, and
wherein
the amount of extra astigmatism monotonically increases along the meridian from a top of the meridian in the intermediate vision region to a bottom of the meridian in the intermediate vision region, or
the amount of extra astigmatism monotonically decreases along the meridian from the top of the meridian in the intermediate vision region to a center of the meridian and monotonically increases from the center of the meridian to the bottom of the meridian in the intermediate vision region.