| 摘要 |
A multifocal lens has an outer surface and an inner surface. The outer surface has at least farsighted region and nearsighted region. The outer surface has an outer surface TC equal to 180 degrees. A thickness of the lens varies from the farsighted region to the nearsighted region in accordance with the outer surface TC. For example, the thickness of the lens increases from the farsighted region to the nearsighted region in accordance with the outer surface TC. The thickness of the lens is a constant in the farsighted region. As a result, it is possible to enlarge the nearsighted region an to prevent distortion in each edge of the lens.
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