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Guoqiang Li, Thomas F Mauger; Passive Adaptive Contact Lens for Correction of Presbyopia. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):2990.
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© ARVO (1962-2015); The Authors (2016-present)
With aging, the crystalline lens of the human eye loses its ability in accommodation, a natural phenomenon called presbyopia. About 42% of American adults are presbyopic, and the number of cases will keep increasing. To care for the vision of such a large population is of great value. Various nonsurgical (spectacles and contact lenses) and surgical techniques have been used. For spectacle and contact lens correction, it is either based on area division which limits field of view or monovision which loses stereopsis. The best solution should allow natural binocular vision. It would be attractive to develop passive adaptive lenses which generate invariant point spread function across an extended depth of field for correction of presbyopia. Here we show that, by engineering the phase profile of the contact lens using special functions, we are able to correct presbyopia with 20/20 to 20/25 visual acuity for near (40 cm), intermediate (70 cm), and distance (4m) vision while maintain natural binocular vision.
We started the design of the phase function with the Gullstrand model eye in which the object is clearly imaged on the retina without accommodation. We then simulate the effect of passive adaptive wavefront-coding on extension of depth of field for near- and intermediate-vision. In contrast to the binary phase function, for the first time to our knowledge, we are investigating other symmetric and nonsymmetric phase functions for contact lens design. The wavefront coding is optimized by considering the consistency of the modulation transfer function for different object distances, different fields at each object distance, and at different wavelengths.
As an example, we have demonstrated the efficacy of the passive adaptive contact lens for correction of presbyopia by optimizing the lens profile using the cubic phase function. For the emmetropic eye with presbyopia (3 mm pupil), the image for near vision is greatly blurred. In contrast, using the passive adaptive wavefront coding technique, all the images through the large depth of field are almost the same, verifying the capability of offering 20/20 vision for all the vision tasks.
The passive adaptive contact lens can provide 20/20 to 20/25 visual acuity for all the vision tasks to the prebyopic eyes. This new technique may have the potential to revolutionize the field of vision care.
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