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Carmen Canovas, Aixa Alarcon, Jacolien Graver, Henk A Weeber, Patricia A Piers; Preclinical evaluation of tolerance to astigmatism with an extended range of vision IOL. Invest. Ophthalmol. Vis. Sci. 2016;57(12):3127. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
The purpose of this study is to preclinically evaluate the tolerance to astigmatism of a new diffractive intraocular lens (IOL) designed to extend the range of vision (ERV) and to compare it to that of a monofocal and multifocal IOL.
Optical and visual performance of an aspheric monofocal, diffractive bifocal (+4D add power) and ERV IOL designs were evaluated in the presence of up to 1D of corneal astigmatism for different pupil sizes. Through focus Modulation Transfer Function (MTF) and USAF pictures were measured on an optical bench by placing trial lenses in front of the eye model to simulate corneal astigmatism. Visual performance was assessed by computer simulated defocus curves. A set of 46 physiological model eyes that included higher order aberrations (Weeber, Featherstone & Piers et al JBO2010) were used to predict the clinical defocus curves for the three IOL models in the presence of different levels of astigmatism.
For all designs and pupil sizes, simulated visual acuity (VA) at best focus decreased linearly in the presence of astigmatism. The amount of astigmatism that provided a distance VA of 20/20 was similar for the monofocal and ERV designs, 1.25D and 0.75D for 3 and 4mm pupils respectively. For the multifocal design, this tolerance was reduced to less than 0.10D for the largest pupil size. The through focus range of vision above 20/20 was not affected by the presence of 0.50D of astigmatism for the monofocal or for the ERV design, being 0.50D and 1.50D respectively. On the optical bench, astigmatism reduced the best focus MTF at 50cpmm for all IOL models, indicating a loss of contrast. For the ERV, MTF at 50cpmm in the presence of 0.75D of cylinder was comparable to the MTF of the multifocal IOL free of astigmatism.
This study preclinically assessed the tolerance to astigmatism of different IOL models. Computer simulations and optical bench testing showed that the distance and through focus performance of the ERV design is preserved in the presence of astigmatism, demonstrating the robustness of the ERV design in the presence of astigmatic errors.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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