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Maria Vinas, Ana Gonzalez-Ramos, Carlos Dorronsoro, Vyas Akondi, nuria Garzon, Francisco Poyales, Susana Marcos; In vivo measurement of longitudinal chromatic aberration with multifocal diffractive intraocular lenses.. Invest. Ophthalmol. Vis. Sci. 2017;58(8):337. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Longitudinal Chromatic Aberration (LCA) plays an important role on polychromatic optical quality, and it is particularly relevant in subjects implanted with diffractive intraocular lenses (IOLs), where the chromatic aberration of the ocular elements and the refractive component of the IOL are added to the chromatic effects of the diffractive design. We used a custom polychromatic Adaptive Optics (AO) system to measure the LCA by both psychophysical methods and in vivo double-pass (DP) retinal imaging in patients bilaterally implanted with hydrophilic trifocal diffractive IOLs.
A supercontinuum laser (450-1020nm) was used as the light source in an AO system provided with:(1) a Hartmann-Shack wavefront sensor,(2) a deformable mirror (HASO&MIRAO,Imagine Eyes), -used in this study to correct the aberrations of the system;(3) a motorized Badal system,(3) a pupil monitoring system,(4) a DP retinal imaging channel, and (5) a psychophysical channel with monochromatically illuminated stimuli.10 patients (66.42±3.8yrs;0.18±0.14D) bilaterally implanted with hydrophilic trifocal diffractive IOLs (Physiol, Belgium) participated in the study.Measurements were performed in both eyes with dilated pupils (4-mm artificial pupil) at 3 different viewing distances (0D/+1.75D/+3.50D) achieved with the Badal system.Subjective best focus of monochromatic stimuli at 5 wavelengths (λ) (480,532,555,650&700nm) was obtained using the Badal system.Best focused images of through-focus (0.25D steps) DP aerial image series were obtained at 3 λ (480,555&700nm).LCA was computed from fitted chromatic difference of focus curves (objective and subjective) as the difference between 480 and 700nm at near, intermediate and far.
The average subjective-LCA was 0.64±0.04D for far, 0.23±0.05D for intermediate and 0.17±0.05D for near.The average objective-LCA was 0.56±0.21D for far, 0.24±0.19D for intermediate and 0.15±0.18D for near.
Objective-LCA is lower than subjective-LCA in agreement with previous studies on phakic, and monofocal IOL implanted patients, consistent with a λ-dependence of the reflecting retinal layers.LCA at far is driven by refraction,while the diffractive design lowers LCA at intermediate and near.In vivo measurements of LCA allow understanding the relative contribution of refractive and diffractive LCA and eventually optimize IOL designs to improve polychromatic image quality.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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