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OptiVis™: Papers


Article Summary

  1. Light distribution between different foci of a multifocal optic plays an important role in retinal image quality in terms of contrast sensitivity and halo/glare. The paper compares light distributions between OptiVis diffractive multifocal lens that incorporates intermediate foci in addition to far and near with other multifocal optics such as Tecnis multifocal, ReStor and Acri.Lisa designed to include far and near foci only (*). The paper demonstrates percentages of light distribution between far, intermediate and near in OptiVis design vs. other lenses.
  2. The paper offers simple formulas to calculate light distribution in a diffractive multifocal optic depending on its diffractive groove heights. The formulas were used to minimize light loss directed outside the vision range from far to near and determine light distribution by different diffractive multifocal lenses at different wavelengths, i.e. different color of light - red, green and blue. The commonly reported light distribution by all manufacturers of multifocal optic is for green light (0.55 micron) associated with a peak of retinal chromatic sensitivity. However, light distribution in diffractive multifocal optic might be highly dependent on wavelength and image quality might be highly sensitive to a color of a viewing object.
  3. Another important factor of light distribution in a diffractive multifocal optic is the fraction of light directed outside far-to-near vision range, so called light loss. This light loss contributes to image blur of a retinal image thus reducing its contrast and effecting halo and glare - larger light loss, higher potential for halo and glare perception. The paper demonstrates how light loss can be reduced with more unequaled far-to-near light split. This principle was used in optimizing apodization of OptiVis diffractive optic by minimizing the area of its diffractive surface that produces close to equal far-to-near light split. This optimization reduced light loss in OptiVis to a single digit, not more than 4% of total light, as compared with other diffractive multifocal designs that demonstrate light loss in double digits - 19% by Tecnis multifocal due to equal far-to-near light split, reduction to 15% by Acry.Lisa due to unequal far-to-near light split and phase subzones and reduction 15% by ReStor lens at 3 mm pupil due to its diffractive surface apodization (**).
  4. In terms viewing objects of different colors, the paper demonstrates that the far-to-near light ratio provided by Tecnis multifocal, ReStor and Acri.Lisa changes by factors of 3 to 4 between blue and red colors of light indicating a potential for a high sensitivity of retinal image quality to a color of a viewing object. Far-to-near light ratio by OptiVis is only a factor of 1.6 indicating that retinal image quality produced by OptiVis diffractive multifocal IOL is by factor of 2 less sensitive to a color variation of viewing objects than other diffractive multifocal lenses.
  5. Overall, the OptiVis optics represent improvement over prior multifocal designs in terms of the inclusion of intermediate foci to provide predictable intermediate vision, minimizing light loss to reduce a potential for halo / glare and substantially reducing image quality variation with color of a viewing object.
  • (*) OptiVis IOL introduces intermediate foci by refractive means by including central refractive zone of progressive power for continuous vision between far and near foci. Recently introduced by PhysIOL "Finevision" trifocal lens provides an intermediate focus by diffractive means. Both lenses represent the next generation of diffractive multifocal IOLs to more closely emulate natural accommodation from far through intermediate to near.
  • (**) Light loss of ReStor lens is further reduced with increased pupil size, nevertheless, elderly patients commonly experience Myosis that limits their pupil sizes and thus do not take full advantage of ReStor's IOL apodization.