Importance

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Abstract

A focal lens for eyeglasses includes a distance area located at an upper part of the lens, a reading area located at a lower part of the lens, and a progressive area located between the distance area and the reading area. A meridional line extends generally vertically through a center of the lens and separates the lens into a nose-side area and an ear-side area. The meridional line is shifted toward the nose-side area in the progressive area and the reading area. Equi-stigmatism curves are arranged in both the nose-side area and the ear-side area, with the distribution of the astigmatism on the ear-side being asymmetrical to the distribution of astigmatism on the nose-side. The astigmatism in the progressive area increases more slowly toward the nose-side than the astigmatism directed toward the ear-side. The progressive area includes vertical distortions which are slightly greater on the nose-side than on the ear-side at an upper part and slightly smaller on the nose-side than on the ear-side at a lower part of the progressive area.

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First Claim