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David Rio, Kelly WOOG, Richard Legras; Simulation of commercial versus theoretically optimized contact lenses. Invest. Ophthalmol. Vis. Sci. 2016;57(12):6250.
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© ARVO (1962-2015); The Authors (2016-present)
Based on image simulation, we aimed to compare through-focus image qualities (TFIQ) with optical profiles measured on various multifocal contact lenses and theoretically optimized bifocal profiles.
The subjective image quality was assessed using a continuous 5-items grading scale. Twenty young normally sighted subjects judged 3 times the quality of computationally blurred images through a 3-mm artificial pupil limiting the impact of their aberrations. The simulated images were calculated for a 4.5-mm pupil diameter from -5 to +2 D each 0.25 D and with 10 optical profiles. We based our simulation on published measurements of the optical profiles of 4 highest addition multifocal contact lenses : Oasys for presbyopia®, Biofinity Multifocal®, Air Optix Aqua Multifocal® and Purevision Multifocal®. These optics were compared to previously published optimized bifocal optical profiles with 2, 5 and 8 concentric zones and their variants including spherical aberrations (SA), and finally a combination of SA. To quantify the efficiency of an optical profile, we calculated, based on the TFIQ score, Depth-of-Focus (i.e. DoF, range of proximities over which an acceptable level of vision is obtained), and the benefit defined as the area under the through-focus subjective quality of vision curve higher than 2 (i.e. level from which the quality of vision becomes acceptable). This criterion was normalized by the naked eye condition.
TFIQ score showed large inter-individual variation, but the average curve was similar to previously published TFIQ score. Except with the Oasys profile, the other commercial profiles provided TFIQ curves with only one peak of quality. Based on DoF and benefit criteria, commercial profiles did not provide acceptable distance and near qualities of vision. The eight concentric zone profile was found to be the most efficient optic. Adding combinations of SA to a bifocal profile degraded the benefit. We could split the population into 3 groups as a function of the advantage they could obtain whatever the tested optics (i.e. a degradation, no difference or a large benefit), explaining why some subjects could never be satisfied with multifocal contact lenses.
Image simulation allows to efficiently evaluate optical profiles and permits to determine that optimized profiles could be better than tested commercial optics.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Benefit as a function of Depth-of-Focus for the 10 tested profiles
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