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Derek Nankivil, Austin Roorda, Nadav Ivzan, Martin Banks; Modelling the expected effect of correcting chromatic aberration on visual performance. Invest. Ophthalmol. Vis. Sci. 2022;63(7):4546 – F0460.
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© ARVO (1962-2015); The Authors (2016-present)
Longitudinal Chromatic Aberration (LCA) and Transverse Chromatic Aberration (TCA) adversely affect retinal image quality. Thus, one expects improved visual performance when chromatic aberrations are minimized or eliminated. Systematic evaluation of the impact of LCA and/or TCA correction under broadband illumination is needed. The purpose of this study is to characterize the expected impact of LCA and/or TCA correction under ecologically valid broadband illumination.
Simulations utilized an ocular wavefront with +3D of spherical error and +0.06D/mm2 of spherical aberration and a wavefront correction with a spherical aberration of -0.06D/mm2 and a paraxial power of -2.87D. Entrance pupil diameter was 4.3mm. LCA was modeled using Thibos et al.’s (1992) chromatic eye and TCA was modeled using Thibos’s (1987) modified Gullstrand reduced-eye model. Considering the human population, a range of LCA, TCA or both LCA and TCA were modeled, such that low LCA = 1.29D, high LCA = 3.57D, low TCA = 0.4, 0.2 arcmin, and high TCA = 6.3, 3.1 arcmin in the sagittal and transverse meridians from λ = 400 to 700nm. The spectral weighting function was derived considering three OLED stimuli (white, purple, and green). With the purple stimulus, luminance was equal for all three primaries. The normalized cumulative photopic efficacy weighted foveal Point Spread Function (PSF) and Modulation Transfer Function (MTF) were calculated. To provide an estimate of the perceptual impact of chromatic aberrations, the areas of the MTF from 3 to 12cpd with and without LCA and/or TCA correction were compared.
The area of the photopic efficacy weighted MTF is reduced by approximately 4 to 30%, 13 to 57%, and 1 to 16% due to low and high amounts of LCA and 0 to 12%, 0 to 32%, and 0 to 2% due to low and high amounts of TCA for white, purple, and green stimuli, respectively. Collectively, typical ocular LCA and TCA reduces the area of the photopic efficacy weighted MTF by approximately 4 to 33% for white stimuli, 13 to 59% for purple stimuli, and 1 to 18% for green stimuli.
Chromatic aberration varies widely in the population. Many subjects have negligible foveal TCA, while all subjects have a substantial amount of LCA. Thus, LCA correction improves visual performance more than TCA correction. Correction of LCA should result in salient improvements in visual performance with either white or purple stimuli.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.
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