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Advanced Optical Wavefront Technologies to Improve Patient Quality of Vision and Meet Clinical Requests. Polymers (Basel) 2022; 14:polym14235321. [PMID: 36501713 PMCID: PMC9741482 DOI: 10.3390/polym14235321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/28/2022] [Accepted: 12/01/2022] [Indexed: 12/09/2022] Open
Abstract
Adaptive optics (AO) is employed for the continuous measurement and correction of ocular aberrations. Human eye refractive errors (lower-order aberrations such as myopia and astigmatism) are corrected with contact lenses and excimer laser surgery. Under twilight vision conditions, when the pupil of the human eye dilates to 5-7 mm in diameter, higher-order aberrations affect the visual acuity. The combined use of wavefront (WF) technology and AO systems allows the pre-operative evaluation of refractive surgical procedures to compensate for the higher-order optical aberrations of the human eye, guiding the surgeon in choosing the procedure parameters. Here, we report a brief history of AO, starting from the description of the Shack-Hartmann method, which allowed the first in vivo measurement of the eye's wave aberration, the wavefront sensing technologies (WSTs), and their principles. Then, the limitations of the ocular wavefront ascribed to the IOL polymeric materials and design, as well as future perspectives on improving patient vision quality and meeting clinical requests, are described.
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Marcos S, Artal P, Atchison DA, Hampson K, Legras R, Lundström L, Yoon G. Adaptive optics visual simulators: a review of recent optical designs and applications [Invited]. BIOMEDICAL OPTICS EXPRESS 2022; 13:6508-6532. [PMID: 36589577 PMCID: PMC9774875 DOI: 10.1364/boe.473458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 05/02/2023]
Abstract
In their pioneering work demonstrating measurement and full correction of the eye's optical aberrations, Liang, Williams and Miller, [JOSA A14, 2884 (1997)10.1364/JOSAA.14.002884] showed improvement in visual performance using adaptive optics (AO). Since then, AO visual simulators have been developed to explore the spatial limits to human vision and as platforms to test non-invasively optical corrections for presbyopia, myopia, or corneal irregularities. These applications have allowed new psychophysics bypassing the optics of the eye, ranging from studying the impact of the interactions of monochromatic and chromatic aberrations on vision to neural adaptation. Other applications address new paradigms of lens designs and corrections of ocular errors. The current paper describes a series of AO visual simulators developed in laboratories around the world, key applications, and current trends and challenges. As the field moves into its second quarter century, new available technologies and a solid reception by the clinical community promise a vigorous and expanding use of AO simulation in years to come.
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Affiliation(s)
- Susana Marcos
- Center for Visual Sciences; The Institute of Optics and Flaum Eye Institute, University of Rochester, New York 14642, USA
| | - Pablo Artal
- Laboratorio de Optica, Universidad de Murcia, Campus Universitario de Espinardo, 30100, Spain
| | - David A. Atchison
- Centre for Vision and Eye Research, Queensland University of Technology, Brisbane Q, 4059, Australia
| | - Karen Hampson
- Department of Optometry, University of Manchester, Manchester M13 9PL, UK
| | - Richard Legras
- LuMIn, CNRS, ENS Paris-Saclay, Université Paris-Saclay, CentraleSupelec, Université Paris-Saclay Orsay, 91400, France
| | - Linda Lundström
- KTH (Royal Institute of Technology), Stockholm, 10691, Sweden
| | - Geunyoung Yoon
- College of Optometry, University of Houston, Houston, 77004, USA
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On-Line Auto Mass Measurement of Residual Solvent Mass and its Influence on Mechanical Properties of Propellants. PROPELLANTS EXPLOSIVES PYROTECHNICS 2016. [DOI: 10.1002/prep.201600053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
The effects of signal and noise on contrast discrimination are difficult to separate because of a singularity in the signal-detection-theory model of two-alternative forced-choice contrast discrimination (Katkov, Tsodyks, & Sagi, 2006). In this article, we show that it is possible to eliminate the singularity by combining that model with a binocular combination model to fit monocular, dichoptic, and binocular contrast discrimination. We performed three experiments using identical stimuli to measure the perceived phase, perceived contrast, and contrast discrimination of a cyclopean sine wave. In the absence of a fixation point, we found a binocular advantage in contrast discrimination both at low contrasts (<4%), consistent with previous studies, and at high contrasts (≥34%), which has not been previously reported. However, control experiments showed no binocular advantage at high contrasts in the presence of a fixation point or for observers without accommodation. We evaluated two putative contrast-discrimination mechanisms: a nonlinear contrast transducer and multiplicative noise (MN). A binocular combination model (the DSKL model; Ding, Klein, & Levi, 2013b) was first fitted to both the perceived-phase and the perceived-contrast data sets, then combined with either the nonlinear contrast transducer or the MN mechanism to fit the contrast-discrimination data. We found that the best model combined the DSKL model with early MN. Model simulations showed that, after going through interocular suppression, the uncorrelated noise in the two eyes became anticorrelated, resulting in less binocular noise and therefore a binocular advantage in the discrimination task. Combining a nonlinear contrast transducer or MN with a binocular combination model (DSKL) provides a powerful method for evaluating the two putative contrast-discrimination mechanisms.
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García-Guerra CE, Aldaba M, Arjona M, Pujol J. Binocular open-view system to perform estimations of aberrations and scattering in the human eye. APPLIED OPTICS 2015; 54:9504-9508. [PMID: 26560778 DOI: 10.1364/ao.54.009504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We present a system that integrates a double-pass (DP) instrument and a Hartmann-Shack (HS) wavefront sensor to provide information not only on aberrations, but also on the scattering that occurs in the human eye. A binocular open-view design permits evaluations to be made under normal viewing conditions. Furthermore, the system is able to compensate for both the spherical and astigmatic refractive errors that occur during measurements by using devices with configurable optical power. The DP and HS techniques provide comparable data after estimating wavefront slopes with respect to the intersections of an ideal grid and compensating for residual errors caused by the optical defects of the measuring system. Once comparable data is obtained, it is possible to use this combined manner of assessment to provide information on scattering. Measurements in an artificial eye suggest that the characteristics of the ocular fundus may induce deviations of DP with respect to the HS data. These differences were quantified in terms of the modulation transfer function in young, healthy eyes measured in infrared light to demonstrate the potential use of the system in visual optics studies.
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Charman WN, Heron G. Microfluctuations in accommodation: an update on their characteristics and possible role. Ophthalmic Physiol Opt 2015; 35:476-99. [DOI: 10.1111/opo.12234] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 07/23/2015] [Indexed: 11/30/2022]
Affiliation(s)
- W Neil Charman
- Faculty of Life Sciences; University of Manchester; Manchester UK
| | - Gordon Heron
- Vision Sciences; Glasgow Caledonian University; Glasgow UK
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Chirre E, Prieto PM, Artal P. Binocular open-view instrument to measure aberrations and pupillary dynamics. OPTICS LETTERS 2014; 39:4773-5. [PMID: 25121871 DOI: 10.1364/ol.39.004773] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We have designed and built a binocular Hartmann-Shack wave-front sensor using a single microlens array and camera for real-time aberration measurement of both eyes in an open-view configuration. Furthermore, the use of a long wavelength (1050 nm) laser diode makes the illumination source completely invisible, so that measurements can be unobtrusively performed while the subject stares at the visual world under realistic conditions. The setup provides a large dynamic range and simultaneous measurements of convergence, pupil size, accommodation, and aberrations. The open-view design not only offers the possibility of measuring the subject's ocular optics under natural conditions but also allows coupling the device with other existing vision testing instruments and setups, which increases its potential to become a powerful tool for different visual optics studies.
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Jayakumar V, Thapa D, Hutchings N, Lakshminarayanan V. Are the fluctuations in dynamic anterior surface aberrations of the human eye chaotic? OPTICS LETTERS 2013; 38:5208-5211. [PMID: 24322219 DOI: 10.1364/ol.38.005208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The purpose of the study is to measure chaos in dynamic anterior surface aberrations and examine how it varies between the eyes of an individual. Noninvasive tear breakup time and dynamic corneal surface aberrations were measured for two open-eye intervals of 15 s. The maximal Lyapunov exponent (MLE) was calculated to test the nature of the fluctuations of the dynamic anterior surface aberrations. The average MLE for total higher-order aberration (HOA) was found to be small (+0.0102±0.0072) μm/s. No significant difference in MLE was found between the eyes for HOA (t-test; p=0.131). Data analysis was carried out for individual Zernike coefficients, including vertical prism as it gives a direct measure of the thickness of the tear film over time. The results show that the amount of chaos was small for each Zernike coefficient and not significantly correlated between the eyes.
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Abstract
A revision of the current state-of-the-art adaptive optics technology for visual sciences is provided. The human eye, as an optical system able to generate images onto the retina, exhibits optical aberrations. Those are continuously changing with time, and they are different for every subject. Adaptive optics is the technology permitting the manipulation of the aberrations, and eventually their correction. Across the different applications of adaptive optics, the current paper focuses on visual simulation. These systems are capable of manipulating the ocular aberrations and simultaneous visual testing though the modified aberrations on real eyes. Some applications of the visual simulators presented in this work are the study of the neural adaptation to the aberrations, the influence of aberrations on accommodation, and the recent development of binocular adaptive optics visual simulators allowing the study of stereopsis.
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Affiliation(s)
- Enrique Josua Fernández
- Laboratorio de Óptica, Instituto Universitario de investigación en Óptica y Nanofísica (IUiOyN), Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
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Hampson KM, Mallen EAH. Chaos in ocular aberration dynamics of the human eye. BIOMEDICAL OPTICS EXPRESS 2012; 3:863-77. [PMID: 22567581 PMCID: PMC3342193 DOI: 10.1364/boe.3.000863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 03/25/2012] [Accepted: 03/30/2012] [Indexed: 05/22/2023]
Abstract
Since the characterization of the eye's monochromatic aberration fluctuations in 2001, the power spectrum has remained the most widely used method for analyzing their dynamics. However, the power spectrum does not capture the complexities of the fluctuations. We measured the monochromatic aberration dynamics of six subjects using a Shack-Hartmann sensor sampling at 21 Hz. We characterized the dynamics using techniques from chaos theory. We found that the attractor embedding dimension for all aberrations, for all subjects, was equal to three. The embedding lag averaged across aberrations and subjects was 0.31 ± 0.07 s. The Lyapunov exponent of the rms wavefront error was positive for each subject, with an average value of 0.44 ± 0.15 µm/s. This indicates that the aberration dynamics are chaotic. Implications for future modeling are discussed.
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Hampson KM, Mallen EAH. Multifractal nature of ocular aberration dynamics of the human eye. BIOMEDICAL OPTICS EXPRESS 2011; 2:464-70. [PMID: 21412452 PMCID: PMC3047352 DOI: 10.1364/boe.2.000464] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/18/2011] [Accepted: 01/26/2011] [Indexed: 05/21/2023]
Abstract
Ocular monochromatic aberrations display dynamic behavior even when the eye is fixating on a stationary stimulus. The fluctuations are commonly characterized in the frequency domain using the power spectrum obtained via the Fourier transform. In this paper we used a wavelet-based multifractal analytical approach to provide a more in depth analysis of the nature of the aberration fluctuations. The aberrations of five subjects were measured at 21 Hz using an open-view Shack-Hartmann sensor. We show that the aberration dynamics are multifractal. The most frequently occurring Hölder exponent for the rms wavefront error, averaged across the five subjects, was 0.31 ± 0.10. This suggests that the time course of the aberration fluctuations is antipersistant. Future applications of multifractal analysis are discussed.
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Affiliation(s)
- Karen M. Hampson
- Bradford School of Optometry and Vision Science, University of Bradford, Richmond Rd, Bradford BD7 1DP, UK
| | - Edward A. H. Mallen
- Bradford School of Optometry and Vision Science, University of Bradford, Richmond Rd, Bradford BD7 1DP, UK
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Mira-Agudelo A, Lundström L, Artal P. Temporal dynamics of ocular aberrations: monocular vs binocular vision. Ophthalmic Physiol Opt 2010; 29:256-63. [PMID: 19422556 DOI: 10.1111/j.1475-1313.2009.00655.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The temporal dynamics of ocular aberrations are important for the evaluation of, e.g. the accuracy of aberration estimates, the correlation to visual performance, and the requirements for real-time correction with adaptive optics. Traditionally, studies on the eye's dynamic behavior have been performed monocularly, which might have affected the results. In this study we measured aberrations and their temporal dynamics both monocularly and binocularly in the relaxed and accommodated state for six healthy subjects. Temporal frequencies up to 100 Hz were measured with a fast-acquisition Hartmann-Shack wavefront sensor having an open field-of-view configuration which allowed fixation to real targets. Wavefront aberrations were collected in temporal series of 5 s duration during binocular and monocular vision with fixation targets at 5 m and 25 cm distance. As expected, a larger temporal variability was found in the root-mean-square wavefront error when the eye accommodated, mainly for frequencies lower than 30 Hz. A statistically-significant difference in temporal behavior between monocular and binocular viewing conditions was found. However, on average it was too small to be of practical importance, although some subjects showed a notably higher variability for the monocular case during near vision. We did find differences in pupil size with mono- and binocular vision but the pupil size temporal dynamics did not behave in the same way as the aberrations' dynamics.
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Affiliation(s)
- A Mira-Agudelo
- Laboratorio de Optica, Centro de Investigación en Optica y Nanofísica (CiOyN), Universidad de Murcia, Campus de Espinardo Murcia, Murcia 30100, Spain.
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Stark LR, Kruger PB, Rucker FJ, Swanson WH, Schmidt N, Hardy C, Rutman H, Borgovan T, Burke S, Badar M, Shah R. Potential signal to accommodation from the Stiles-Crawford effect and ocular monochromatic aberrations. JOURNAL OF MODERN OPTICS 2009; 56:2203-2216. [PMID: 20835401 PMCID: PMC2934758 DOI: 10.1080/09500340903184295] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The purpose of this study is to determine if cues within the blurred retinal image due to the Stiles-Crawford (SC) effect and the eye's monochromatic aberrations can drive accommodation with a small pupil (3 mm) that is typical of bright photopic conditions.The foveal, psychophysical SC function (17 min arc) and ocular monochromatic aberrations were measured in 21 visually normal adults. The retinal image of a 10.2 min arc disc was simulated for spherical defocus levels of -1 D, 0 D and +1 D in each of four conditions consisting of combinations of the presence or absence of the individual SC function and monochromatic aberrations with a 3 mm pupil. Accommodation was recorded in eleven participants as each viewed the simulations through a 0.75-mm pinhole.The SC effect alone did not provide a significant cue to accommodation. Monochromatic aberrations provided a statistically significant but rather small cue to monocular accommodation.
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Affiliation(s)
- Lawrence R. Stark
- School of Optometry, Queensland University of Technology, Brisbane, Australia
- Southern California College of Optometry, Fullerton, CA, USA
| | - Philip B. Kruger
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Frances J. Rucker
- State University of New York State College of Optometry, Manhattan, NY, USA
- Department of Biology, City University of New York, Manhattan, NY, USA
| | - William H. Swanson
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Nathan Schmidt
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Caitlin Hardy
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Hadassa Rutman
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Theodore Borgovan
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Sean Burke
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Mustanser Badar
- State University of New York State College of Optometry, Manhattan, NY, USA
| | - Raj Shah
- State University of New York State College of Optometry, Manhattan, NY, USA
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