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Multizone Bifocal Contact Lens Design

A satisfactory bifocal contact lens has not yet reached the marketplace because of deficiencies in the present designs. The two-zone concentric design allows both the near and far images to be present simultaneously, however the image quality is not very good. Recently several new bifocal contact lenses with multiple zones have been suggested. This paper presents computer calculations of the image quality of several of these new designs. The zone-plate design, with an intermediate blaze angle, gives the best image quality of the lenses that were examined.