Suchergebnisse

Simultaneous vision is an increasingly used solution for the correction of presbyopia (the age-related loss of ability to focus near images). Simultaneous Vision corrections, normally delivered in the form of contact or intraocular lenses, project on the patient's retina a focused image for near vision superimposed with a degraded image for far vision, or a focused image for far vision superimposed with the defocused image of the near scene. It is expected that patients with these corrections are able to adapt to the complex Simultaneous Vision retinal images, although the mechanisms or the extent to which this happens is not known. We studied the neural adaptation to simultaneous vision by studying changes in the Natural Perceived Focus and in the Perceptual Score of image quality in subjects after exposure to Simultaneous Vision. We show that Natural Perceived Focus shifts after a brief period of adaptation to a Simultaneous Vision blur, similar to adaptation to Pure Defocus. This shift strongly correlates with the magnitude and proportion of defocus in the adapting image. The magnitude of defocus affects perceived quality of Simultaneous Vision images, with 0.5 D defocus scored lowest and beyond 1.5 D scored >sharp>. Adaptation to Simultaneous Vision shifts the Perceptual Score of these images towards higher rankings. Larger improvements occurred when testing simultaneous images with the same magnitude of defocus as the adapting images, indicating that wearing a particular bifocal correction improves the perception of images provided by that correction. © 2014 Radhakrishnan et al. ; The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement n° 294099, Spanish Government grant FIS2011-264605 and 7th Framework Programme of the European Community through the Marie Curie Initial Training Network OpAL (OpAL is an Initial Training Network funded by the European Commission under the Seventh Framework Programme (PITN-GA-2010-264605)) ; Peer Reviewed

14 pags., 9 figs. ; Adaptation to a blurred image causes a physically focused image to appear too sharp, and shifts the point of subjective focus toward the adapting blur, consistent with a renormalization of perceived focus. We examined whether and how this adaptation normalizes to differences in blur between the two eyes, which can routinely arise from differences in refractive errors. Observers adapted to images filtered to simulate optical defocus or different axes of astigmatism, as well as to images that were isotropically blurred or sharpened by varying the slope of the amplitude spectrum. Adaptation to the different types of blur produced strong aftereffects that showed strong transfer across the eyes, as assessed both in a monocular adaptation task and in a contingent adaptation task in which the two eyes were simultaneously exposed to different blur levels. Selectivity for the adapting eye was thus generally weak. When one eye was exposed to a sharper image than the other, the aftereffects also tended to be dominated by the sharper image. Our results suggest that while shortterm adaptation can rapidly recalibrate the perception of blur, it cannot do so independently for the two eyes, and that the binocular adaptation of blur is biased by the sharper of the two eyes' retinal images. ; This study was supported by EY-10834 (MW), Spanish Government Formacion de Personal Investigador (FPI) Predoctoral Fellowship (LS), FIS2008- 02065 (SM) and FIS2011-25637 (SM), and European Research Council ERC-2011-AdG-294099 (SM).

13 págs.; 5 figs. ; © 2015 ARVO. The ability of the visual system to compensate for differences in blur orientation between eyes is not well understood. We measured the orientation of the internal blur code in both eyes of the same subject monocularly by presenting pairs of images blurred with real ocular point spread functions (PSFs) of similar blur magnitude but varying in orientations. Subjects assigned a level of confidence to their selection of the best perceived image in each pair. Using a classification-images–inspired paradigm and applying a reverse correlation technique, a classification map was obtained from the weighted averages of the PSFs, representing the internal blur code. Positive and negative neural PSFs were obtained from the classification map, representing the neural blur for best and worse perceived blur, respectively. The neural PSF was found to be highly correlated in both eyes, even for eyes with different ocular PSF orientations (rPos = 0.95; rNeg = 0.99; p < 0.001). We found that in subjects with similar and with different ocular PSF orientations between eyes, the orientation of the positive neural PSF was closer to the orientation of the ocular PSF of the eye with the better optical quality (average difference was ∼10°), while the orientation of the positive and negative neural PSFs tended to be orthogonal. These results suggest a single internal code for blur with orientation driven by the orientation of the optical blur of the eye with better optical quality. ; The authors acknowledge the funding received from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007- 2013) / ERC Grant Agreement n8 294099 (SM), Spanish Government grant FIS2011-264605 (SM), the 7th Framework Programme of the European Community through the Marie Curie Initial Training Network OpAL (OpAL is an Initial Training Network funded by the European Commission under the Seventh Framework Programme (PITN-GA-2010- 264605, AR) and USA NIH grant R01EY05957 (EP). ; Peer Reviewed

12 págs.; 9 figs.; 1 tab. ; © 2015 ARVO. We studied the role of native astigmatism and ocular aberrations on best-focus setting and its shift upon induction of astigmatism in 42 subjects (emmetropes, myopes, hyperopes, with-the-rule [WTR] and against-the-rule [ATR] myopic astigmats). Stimuli were presented in a custom-developed adaptive optics simulator, allowing correction for native aberrations and astigmatism induction (+1 D; 6-mm pupil). Best-focus search consisted on randomized-step interleaved staircase method. Each subject searched best focus for four different images, and four different conditions (with/without aberration correction, with/without astigmatism induction). The presence of aberrations induced a significant shift in subjective best focus (0.4 D; p < 0.01), significantly correlated (p = 0.005) with the best-focus shift predicted from optical simulations. The induction of astigmatism produced a statistically significant shift of the best-focus setting in all groups under natural aberrations (p = 0.001), and in emmetropes and in WTR astigmats under corrected aberrations (p < 0.0001). Best-focus shift upon induced astigmatism was significantly different across groups, both for natural aberrations and AO-correction (p < 0.0001). Best focus shifted in opposite directions in WTR and ATR astigmats upon induction of astigmatism, symmetrically with respect to the best-focus shift in nonastigmatic myopes. The shifts are consistent with a bias towards vertical and horizontal retinal blur in WTR and ATR astigmats, respectively, indicating adaptation to native astigmatism. ; The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement n. [ERC-2011- AdC 294099]. This study was supported by grants FIS2011-24637 to SM and a collaborative research project funded by Essilor International. Optometric examinations were performed in the Faculty of Optometry Clinic of the University Complutense de Madrid (Madrid, Spain). GM and MH work for Essilor International. ; Peer Reviewed

Orlando, United States, 4–8 May 2014 ; Longitudinal Chromatic Aberration (LCA) plays an important role on polychromatic optical quality and retinal imaging at different wavelengths. However, the reported LCA varies across studies, likely associated to the different measurement techniques. We present LCA obtained from Hartmann-Shack (HS) wavefront sensing, double-pass (DP), and psychophysical methods in the same subjects ; Spanish Government FIS2008-02065, FIS2011-25637, and FPU Programs; European Research Council ERC-2011-AdG-294099; CSIC JAE Predoctoral Program ; EU Marie Curie FP7-PEOPLE- 2010-ITN #26405 ; Peer Reviewed

Vancouver Convention Centre, Vancouver, B.C., April 28 – May 2 (2019) . -- ARVO Annual Meeting Abstract 2019 ; Support Spanish Government RyC-2016-21125, PTQ-15-07432, FPU17/02760, FIS2014-56643-R, FIS2017-84753-R and ISCIII-DTS16-00127, S Madariaga MECD PRX16/00154 + Fulbright CIES FMECD-ST-2016; EU H2020 SME IA GA-739882; EIT Health; ERC-2011-AdC 294099; CAM IND2017/BMD-7670; CAM and Marie Curie Action EU FP7/2007-2013 COFUND 291820 ; Peer reviewed

16 pags. 6 figs., 1 tab. ; Purpose: As multifocal contact lenses (MCLs) expand as a solution for presbyopia correction, a better understanding of their optical and visual performance becomes essential. Also, providing subjects with the experience of multifocal vision before contact lens fitting becomes critical, both to systematically test different multifocal designs and to optimize selection in the clinic. In this study, we evaluated the ability of a simultaneous vision visual simulator (SimVis) to represent MCLs. Methods: Through focus (TF) optical and visual quality with a center-near aspheric MCL (low, medium and high near adds) were measured using a multichannel polychromatic Adaptive Optics visual simulator equipped with double-pass, SimVis (temporal multi-plexing), and psychophysical channels to allow measurements on-bench and in vivo. On bench TF optical quality of SimVis-simulated MCLs was obtained from double-pass (DP) images and images of an E-stimulus using artificial eyes. Ten presbyopic subjects were fitted with the MCL. Visual acuity (VA) and DP retinal images were measured TF in a 4.00 D range with the MCL on eye, and through SimVis simulations of the same MCLs on the same subjects. Results: TF optical (on bench and in vivo) and visual (in vivo) quality measurements captured the expected broadening of the curves with increasing add. Root mean square difference between real and SimVis-simulated lens was 0.031/0.025 (low add), 0.025/0.015 (medium add), 0.019/0.011 (high add), for TF DP and TF LogMAR VA, respectively. A shape similarity metric shows high statistical values (lag κ = 0), rho = 0.811/0.895 (low add), 0.792/0.944 (medium add), and 0.861/0.915 (high add) for TF DP/LogMAR VA, respectively. Conclusions: MCLs theoretically and effectively expand the depth of focus. A novel simulator, SimVis, captured the through-focus optical and visual performance of the MCL in most of the subjects. Visual simulators allow subjects to experience vision with multifocal lenses prior to testing them on-eye. Translational Relevance: Simultaneous visual simulators allow subjects to experience multifocal vision non-invasively. We demonstrated equivalency between real multifocal contact lenses and SimVis-simulated lenses. The results suggest that SimVis is a suitable technique to aid selection of presbyopic corrections in the contactology practice. ; Supported by the European Research Council (ERC-2011-AdC 294099) to SM; Spanish Government (FIS2017-84753R) to SM, and pre-doctoral fellowship (FPU16/01944) to SA; Collaborative agreement with Johnson & Johnson Vision, Inc., Research & Development, Jacksonville, FL, USA.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019 ; Support European Research Council ERC-2011-AdG-294099; Spanish Government: FIS2017-84753-R, PTQ-15-07432, and ISCIII DTS16/00127; Spanish Goverment predoctoral program FPU16/01944; Collaborative agreement with Johnson & Johnson Vision, Inc., Jacksonville, FL, USA ; Peer reviewed