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Pablo De Gracia, Chelsea Des Rosiers, Todd Derek Whitescarver; Segmentation Tools for the Fourier Evaluation of Commercially Avalilable Multifocal Contact Lenses. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6335.
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© ARVO (1962-2015); The Authors (2016-present)
To develop the computational tools that allow for a proper evaluation of the optical properties of commercially available multifocal contact lenses when interacting with the higher order aberrations naturally occurring in subjects eyes. The segmentation method proposed was used in combination with the Visual Strehl Ratio in the Frequency space (VSOTF) metric.
The optical profiles of 12 models of multifocal contact lenses were measured by using the NIMO instrument (Lambda-X). Three corrections (-6 D, -3 D, and +1 D) of each model were measured. The lenses measured included: two Ultra lens models (B&L), three models of the Air Optix Aqua (Alcon), four models of the Biofinity lens (Cooper Vision), and three models of the Oasys lens (J&J).The optical profiles obtained from the NIMO contained 28 points per mm and were translated to their corresponding wavefronts by locally segmenting the pupil. Once the multifocal wavefronts were created, a standard Fourier procedure was applied to obtain the VSOTF through focus between -1 and 5 D. Two values were obtained to compare the optical properties (between optical infinity and a working distance of 20 cm) of the 13 designs: the area under the through focus VSOTF (normalized by the area obtained for the monofocal design) and the interval of acceptable quality through focus.
The area under the through focus VSOTF ranges from 0.80 (Oasys L) to 1.42 (Ultra H) and the range through focus varies from 0.93 D (Oasys L) to 2.73 D (Ultra H). The optical performance of the Oasys M and the Oasys L is comparable to the one produced by a monofocal lens. The contact lenses manufactured by B&L, Alcon, and Cooper Vision, shift the VSOTF towards more positive values when the myopic correction increases.
A new method to evaluate the optical profiles of multifocal contact lenses has been presented. With this method it is possible to observe how designs for old presbyopes - Ultra H, AOA H, Oasys H - spread the VSOTF across around 2.5 D through focus. The peak performance of these designs, however, is lower than the one obtained for lenses that are used by young presbyopes – Ultra L, AOA M and L, Bio 1.50 and 1.00. Designs intended for young presbyopes do not extend the VSOTF more than 2 D but do conserve a higher peak performance that young presbyopes move through focus by using the partial accommodation they still conserve.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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