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7 págs.; 5 figs. ; © 2015 The Association for Research in Vision and Ophthalmology, Inc. PURPOSE. We estimated the contribution of the gradient refractive index (GRIN) and lens surfaces to lens astigmatism and lens astigmatic angle as a function of age in human donor lenses. METHODS. Human lenses were imaged, ex vivo, with 3D-spectral optical coherence tomography (OCT) and their back focal length was measured using laser ray tracing. The contribution of lens surfaces and GRIN to lens astigmatism were evaluated by computational ray tracing on the GRIN lens and a homogenous equivalent index lens. Astigmatism magnitude and relative astigmatic angle of and between lens surfaces, GRIN lens, and lens with homogeneous refractive index were evaluated, and all results were correlated with age. RESULTS. The magnitude of astigmatism in the anterior lens surface decreased with age (slope = -0.005 diopters [D]/y; r = 0.397, P =0.018). Posterior surface astigmatism and lens astigmatism were not age-dependent. Presence of GRIN did not alter significantly the magnitude or axis of the lens astigmatism. The astigmatism of GRIN lens and lens with homogeneous refractive index correlated with anterior lens surface astigmatism (GRIN, P = 3.9E - 6, r = 0.693; equivalent refractive index lens, P = 4.1E - 4, r = 0.565). The astigmatic angle of posterior surface, GRIN lens, and homogeneous refractive index lens did not change significantly with age. CONCLUSIONS. The axis of lens astigmatism is close to the astigmatic axis of the anterior lens surface. Age-related changes in lens astigmatism appear to be related to changes in the anterior lens astigmatism. The influence of the GRIN on lens astigmatism and the astigmatic axis is minor. ; Supported by Spanish Government Grant FIS2011-25637 (SM), Consejo Superior de Investigaciones Científicas Junta de Ampliacion de Estudios (CSIC JAE)-Pre Program (JB), CSIC i-LINKþ 2012, iLINKþ0609 (SM). 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 294099 (SM). ; Peer Reviewed

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019 ; Support European Project Multiply H-2020-MSCA-COFUND-2015 Ref. 713694, Spanish Government Grant FIS2017-84753-R, European Project Presbyopia ERC-2011-AdG Ref. 294099, European Project Imcustomeye H2020-ICT-2017 Ref. 779960, BES-2015-072197 ; Peer reviewed

9 pags.; 6 figs.; 2 tabs.; . Published by SPIE under a Creative Commons Attribution 3.0 Unported License. ; Measurement of intraocular lens (IOL) alignment implanted in patients in cataract surgery is important to understand their optical performance. We present a method to estimate tilt and decentration of IOLs based on optical coherence tomography (OCT) images. En face OCT images show Purkinje-like images that correspond to the specular reflections from the corneal and IOL surfaces. Unlike in standard Purkinjeimaging, the tomographic nature of OCT allows unequivocal association of the reflection with the corresponding surface. The locations of the Purkinje-like images are linear combinations of IOL tilt, IOL decentration, and eye rotation. The weighting coefficients depend on the individual anterior segment geometry, obtained from the same OCT datasets. The methodology was demonstrated on an artificial model eye with set amounts of lens tilt and decentration and five pseudophakic eyes. Measured tilt and decentration in the artificial eye differed by 3.7% and 0.9%, respectively, from nominal values. In patients, average IOL tilt and decentration from Purkinje were 3.30 ± 4.68 deg and 0.16 ± 0.16 mm, respectively, and differed on average by 0.5 deg and 0.09 mm, respectively, from direct measurements on distortion-corrected OCT images. Purkinje-based methodology from anterior segment en face OCT imaging provided, therefore, reliable measurements of IOL tilt and decentration. © The Authors. ; This study has been funded by Spanish Government Grant No. FIS2011-25637 and European Research Council ERC-2011 AdG-294099 "Bio-inspired optical correction of presbyopia" to S. Marcos, and Marie Curie Actions-Networks of Initial Training (ITN) FP7-PEOPLE-2010-ITN 264605 (OpAL-Optical and adaptational limits of vision). ; Peer Reviewed

13 pags., 7 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; Earlier studies have shown that the gradient index of refraction (GRIN) of the crystalline lens can be reconstructed in vitro using Optical Coherence Tomography (OCT) images. However, the methodology cannot be extended in vivo because it requires accurate measurements of the external geometry of the lens. Specifically, the posterior surface is measured by flipping the lens so that the posterior lens surface faces the OCT beam, a method that cannot be implemented in vivo. When the posterior surface is imaged through the lens in its natural position, it appears distorted by the unknown GRIN. In this study, we demonstrate a method to reconstruct both the GRIN and the posterior surface shape without the need to flip the lens by applying optimization routines using both on-axis and off-axis OCT images of cynomolgous monkey crystalline lenses, obtained by rotating the OCT delivery probe from -45 to +45 degrees in 5 degree steps. We found that the GRIN profile parameters can be reconstructed with precisions up to 0.009, 0.004, 1.7 and 1.1 (nucleus and surface refractive indices, and axial and meridional power law, respectively), the radius of curvature within 0.089 mm and the conic constant within 0.3. While the method was applied on isolated crystalline lenses, it paves the way to in vivo lens GRIN and posterior lens surface reconstruction. ; European Research Council (ERC) under European Union's Horizon 2020 research and innovation programme (H2020-MSCA COFUND-2015 FP-713694, MULTIPLY); Spanish government (FIS2014-56643-R, FIS2017-84753-R); European Research Council under the European Union's Seventh Framework programme (ERC-2011-AdG-2940); National Eye Institute (R01EY021834; F31EY021444); Ruth L. Kirschstein National Research Service Award Individual Pre-doctoral Fellowship (P30EY14801 Center Core Grant); the Florida Lions Eye Bank and Beauty of Sight Foundation; the Henri and Flore Lesieur Foundation.

11 pags., 8 figs. ; Purpose. To estimate changes in surface shape and gradient refractive index (GRIN) profile in primate lenses as a function of accommodation. To quantify the contribution of surface shape and GRIN to spherical aberration changes with accommodation. Methods. Crystalline lenses from 15 cynomolgus monkeys were studied in vitro under different levels of accommodation produced by a stretching system. Lens shape was obtained from optical coherence tomography (OCT) cross-sectional images. The GRIN was reconstructed with a search algorithm using the optical path measured from OCT images and the measured back focal length. The spherical aberration of the lens was estimated as a function of accommodation using the reconstructed GRIN and a homogeneous refractive index. Results. The lens anterior and posterior radii of curvature decreased with increasing lens power. Both surfaces exhibited negative asphericities in the unaccommodated state. The anterior surface conic constant shifted toward less negative values with accommodation, while the value of the posterior remained constant. GRIN parameters remained constant with accommodation. The lens spherical aberration with GRIN distribution was negative and higher in magnitude than that with a homogeneous equivalent refractive index (by 29% and 53% in the unaccommodated and fully accommodated states, respectively). Spherical aberration with the equivalent refractive index shifted with accommodation toward negative values (-0.070 lm/diopter [D]), but the reconstructed GRIN shifted it farther (-0.124 lm/ D). Conclusions. When compared with the lens with the homogeneous equivalent refractive index, the reconstructed GRIN lens has more negative spherical aberration and a larger shift toward more negative values with accommodation. © 2013 The Association for Research in Vision and Ophthalmology, Inc. ; Supported by a Spanish government Grant FIS2011-25637 and the European Research Council ERC-AdG-294099 (SM); CSIC JAE-Pre Program fellowship (JB); CSIC i-LINKþ 2012, iLINKþ0609 (SM, J-MP); National Eye Institute Grants 2R01EY14225, 1R01EY021834, 1F31EY021444 (NSRA Individual Predoctoral Fellowship [BM]), P30EY14801 (Center Grant); the Florida Lions Eye Bank; the Henri and Flore Lesieur Foundation (J-MP); Research to Prevent Blindness; the Vision Cooperative Research Centre, Sydney, New South Wales, Australia; and the Australian Federal Government through the Cooperative Research Centres Programme

In vivo three-dimensional (3-D) anterior segment biometry before and after cataract surgery was analyzed by using custom highresolution high-speed anterior segment spectral domain Optical Coherence Tomography (OCT). The system was provided with custom algorithms for denoising, segmentation, full distortion correction (fan and optical) and merging of the anterior segment volumes (cornea, iris, and crystalline lens or IOL), to provide fully quantitative data of the anterior segment of the eye. The method was tested on an in vitro artificial eye with known surfaces geometry at different orientations and demonstrated on an aging cataract patient in vivo. Biometric parameters CCT, ACD/ILP, CLT/ILT Tilt and decentration are retrieved with a very high degree of accuracy. IOL was placed 400 οm behind the natural crystalline lens, The IOL was aligned with a similar orientation of the natural lens (2.47 deg superiorly), but slightly lower amounts (0.77 deg superiorly). The IOL was decentered superiorly (0.39 mm) and nasally (0.26 mm). © 2013 Optical Society of America. ; This study has been funded by Spanish Government Grant FIS2011-25637 and European Research Council Grant ERC-2011-AdG-294099 to S. Marcos. ; Peer Reviewed

ARVO Annual Meeting Abstract ; Support European Project COFUND Multiply H-2020-MSCA-COFUND-2015 Ref. 713694; European Project IMCUSTOMEYE H2020-ICT-2017 Ref. 779960; European Project MyFUN H2020-MSCA-ITN-2015 Ref. 675137; Spanish government grant FIS2017-84753-R ; Peer reviewed

1 pag. -- This is a 2020 ARVO Annual Meeting abstract. ; Support European Project COFUND Multiply H-2020-MSCA-COFUND-2015 Ref. 713694; European Project IMCUSTOMEYE H2020-ICT-2017 Ref. 779960; European Project MyFUN H2020-MSCA-ITN-2015 Ref. 675137; Spanish government grant FIS2017-84753-R ; Peer reviewed