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SARA AISSATI, Maria Vinas, Clara Benedi-Garcia, Carlos Dorronsoro, Susana Marcos; Testing the effect of ocular aberrations on perceived Transverse Chromatic Aberration. Invest. Ophthalmol. Vis. Sci. 2019;60(9):601. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
In polychromatic light, the retinal image is affected by monochromatic (MC) and chromatic (C) aberrations (longitudinal,LCA & transverse,TCA). LCA is typically measured objectivelly and psychophysically. TCA measurements are scarcer and the impact of all combined factors on vision seldom investigated. A new channel in an Adaptive Optics (AO) visual simulator allowed to measure TCA under controlled aberrations
A custom polychromatic AO-system was used to measure (Hartman-Shack HS, HASO, Imagine eyes) and correct aberrations(electromagnetic deformable mirror, MIRAO). TCA was measured with 2-D Vernier alignment technique. The stimulus consisted of 2 concentric color squares (40 - 120 arcmin; central red/external blue), with a static black cross in the periphery and adjustable central cross in the center (2-arcmin lines). The central cross is projected in Digital Micro-Mirror Device (DMD), illuminated simultaneously with 490 & 680nm from the supercontinuum laser source, and subjects could adjust it to align with a keyboard. LCA was obtained from chromatic difference of subjective focus of MC stimuli (pLCA) and HS-based defocus at different wavelengths (oLCA), 490-700nm range (6mm pupil). LCA & TCA were measured on 7 subjects (24.7±1.25yrs;-0.39±0.75D) with paralyzed accommodation, with AO & NoAO, for 6 & 2mm pupil size (pTCA & oTCA)
LCA agreed with prior literature, with an offset (0.60D) between pLCA & oLCA values, and non-affected by AO:pLCA 1.30±0.06D(NoAO),1.39±0.12D(AO) & oLCA 0.77±0.20D(NoAO), 0.86±0.22D(AO). TCA was highly repetitive(avg std: 0.34 arcmin). TCA varied across subjects/conditions, with avg pTCA:0.97±0.32(NoAO), pTCA:1.72±0.58(AO), oTCA:1.76±0.24 (NoAO), oTCA: 1.45±0.24(AO) arcmin. On avg, increasing pupil size shifted TCA inferiorly 0.79±0.47(NoAO),& 0.27±0.69(AO) arcmin. AO-correction shifted pTCA 0.40±0.10 arcmin nasally & 0.12±0.14 arcmin superiorly & oTCA 0.49±0.04 inferiorly & -0.08±0.08 arcmin nasally. TCA shifted with decreasing pupil size in 6 subjects with NoAO (avg shift 55.26%) & in 3 subjects with AO (avg shift 18.59%)
While LCA is independent on the presence of aberrations, TCA is highly dependent, as indicated by significant changes with increasing pupil size and AO. Differences may additionally arise from Stiles-Crawford effect and interactions of LCA-MC. MC aberration, pLCA & TCA should be included in polychromatic optical quality calculations
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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