Abstract
There are several designs of contact lenses currently available for the correction of presbyopia. No lens comes close to the ideal of providing a correction appropriate to the object of regard which covers the full entrance pupil of the eye1. Of interest are the compromises offered by specific designs and how well their on-eye performance compares with both their theoretical performance and in vitro measurements made on the lenses. One of the current classes of design consists of concentric simultaneous vision varifocal lenses. These lenses are usually limited to radial power profiles. The available range of corrective power under any particular set of lighting conditions is dependent on the pupil diameter of the individual wearer. The lens design usually cannot be modified to match the pupil diameter of the individual nor to increase the effective reading addition for the aging presbyope1. Their smooth variation in power is presumed to give reasonably good visual performance for a wide range of object distances. Moreover, unlike alternating designs, concentric varifocals give adequate near vision for all directions of gaze, and do not require decentration, which is difficult to achieve with soft lenses.
© 1993 Optical Society of America
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