摘要 |
A contact lens has front and rear surfaces, the rear surface having a base curve fits the eye of a wearer. The front surface has a central circular zone which is substantially spherical and which, together with the base curve, generates a central zone power selected so as to correct near vision of the wearer. The front surface also has an annular outer zone which is substantially spherical and which, together with the base curve, generates an outer zone power which is less than the central zone power. The front surface further includes an annular region, intermediate the central and outer zones, having one or more contiguous intermediate annular zones, each of which is substantially spherical. The one or more intermediate annular zones generate respective one or more intermediate zone refractive powers in a monotonic progression of decreasing refractive power from the central zone to the annular outer zone.
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