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Larry N Thibos, Tao Liu; Customized optical models describe ocular aberrations across the visual field during accommodation. Invest. Ophthalmol. Vis. Sci. 2019;60(9):1404. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
We aimed to create customized optical models of the eye that accurately reproduce the wavefront aberrations of individual eyes across the visual field at different accommodative states, thus providing a mechanistic explanation for the changes in the eye’s aberration structure due to accommodation.
Structural parameters of a generic eye model were optimized using optical design software to account for published measurements of wavefront aberrations measured for 19 individuals at 37 test locations over the central 30° diameter visual field at 8 levels of accommodative demand. Biometric data for individual eyes were used as starting values and normative data were used to constrain optimizations to ensure anatomically reasonable values.
Customized models of the accommodating eye model accurately accounted for ocular aberrations over the central 30 deg. of visual field with an averaged RMS fitting error typically < 0.2 μm at any given field location (less than Rayleigh's λ/4 criterion for diffraction-limited accuracy). Optimized structural parameters of the eye models were anatomically reasonable and they changed in the expected way when accommodating (e.g. curvature of both surfaces of the lens increase, anterior chamber shortens, and the lens thickens). Accuracy for representing spherical aberration was significantly improved by relaxing anatomical constraints on the anterior surface of the lens to compensate for a simplifying assumption of uniform-index media. Use of the model to compute retinal image quality revealed large penalties of accommodative lag for activating photoreceptor signals that may be relevant to the visual control of eye growth.
Functional models of the accommodating eye that are anatomically similar and functionally equivalent to individual human eyes provide accurate, efficient representation of ocular aberration structure across the visual field. Future applications may include computing retinal image quality, assessing the optical limits to vision, designing devices to modify or correct the eye’s optical flaws, and understanding the role of vision in the control of eye growth.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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