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Petelczyc K, Bolek J, Kakarenko K, Krix-Jachym K, Kołodziejczyk A, Rękas M. Use of the perceptual point-spread function to assess dysphotopsias. PLoS One 2024; 19:e0306331. [PMID: 39028737 PMCID: PMC11259305 DOI: 10.1371/journal.pone.0306331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 06/14/2024] [Indexed: 07/21/2024] Open
Abstract
Nowadays many patients are choosing EDOF or multifocal lenses for replacement of natural lens in cataract surgery. This can result in issues such as presence of dysphotopsias, namely halo and glare. In this work, we propose a new perimetry method to describe dysphotopsias in far-field region in a presence of bright, point-like light source. We constructed a custom device and designed measurement procedure for quantitative measurement of dysphotopias in the center of visual field and used it to examine patients with mild cataracts or implanted IOLs. Our approach may help in establishing an objective method to study and compare dysphotopsias.
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Affiliation(s)
| | - Jan Bolek
- Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
| | - Karol Kakarenko
- Faculty of Physics, Warsaw University of Technology, Warsaw, Poland
| | | | | | - Marek Rękas
- Ophthalmology Department, Military Institute of Medicine, Warsaw, Poland
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2
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De Gracia P. Fourier tools for the evaluation of refractive multifocal designs. Sci Rep 2023; 13:22585. [PMID: 38114735 PMCID: PMC10730910 DOI: 10.1038/s41598-023-50172-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/15/2023] [Indexed: 12/21/2023] Open
Abstract
This paper presents innovative tools and methodologies for the theoretical assessment of optical properties in refractive multifocal designs. Utilizing lens segmentation techniques and classical Fourier optics, these tools can be of help evaluating multifocal contact lenses, intraocular lenses, small aperture designs, and corneal inlays. As an example of their utility, this study presents the through-focus Visual Strehl ratios in the frequency domain of 12 multifocal contact lenses from four companies, derived from the sagittal power profiles obtained with a NIMO equipment (LAMBDA-X) for three base prescriptions (- 6.00 D, - 3.00 D, and + 1.00 D). The contact lenses are also assessed alongside higher-order aberrations obtained from 65 eyes, measured using a Wavefront Sciences Complete Ophthalmic Analysis System (AMO). Diameter variations, corresponding to individual pupil sizes (2.45-6.27 mm), were considered in the evaluation. These novel tools enable the theoretical evaluation of multifocal solutions without the need for prototypes. In the case examples presented, they differentiate between lenses tailored for different presbyopic age groups, offer guidance on optimizing hyperfocal distance in contact lens design, and underscore the relevance of the effective aperture effect. Notably, this paper introduces the pioneering conversion of sagittal powers of multifocal solutions into an equivalent wavefront and optical quality metric, with potential applications in myopia control assessments. The author hopes that readers recognize and utilize these tools to advance the field of refractive multifocality.
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Affiliation(s)
- Pablo De Gracia
- School of Optometry, University of Detroit Mercy, Novi, 48377, MI, USA.
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3
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Sánchez RF, Puertas FJ, Issolio LA. Modulation transfer function formula for different age ranges. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:1979-1985. [PMID: 37855554 DOI: 10.1364/josaa.494721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 09/19/2023] [Indexed: 10/20/2023]
Abstract
The modulation transfer function (MTF) is one of the most complete tools to study the optical performance of the eye. We present the average radial MTF profiles measured in 68 subjects grouped in six age ranges (from 20 to 80 years) and a general formula to estimate the radial profile of human MTF as a function of pupil size and age. The mean MTF for each age group was fitted to an analytical expression to compute two parameters related to aging. The proposed formula fitted reasonably well to experimental data available in previous works and predicted the average changes with aging of different optical quality parameters obtained from MTF.
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Barcala X, Zaytouny A, Rego-Lorca D, Sanchez-Quiros J, Sanchez-Jean R, Martinez-de-la-Casa JM, Dorronsoro C, Marcos S. Visual simulations of presbyopic corrections through cataract opacification. J Cataract Refract Surg 2023; 49:34-43. [PMID: 35971215 PMCID: PMC9794132 DOI: 10.1097/j.jcrs.0000000000001040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 08/01/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To study the viability of visual simulation of presbyopic correction in patients with cataract and the effect and impact of the cataract on the perceived visual quality of the different simulated presbyopic corrections preoperatively and postoperatively. SETTING San Carlos Clinical Hospital, Madrid, Spain. DESIGN Observational, noninterventional, pilot study, early feasibility of the device being studied. METHODS Cataract patients were tested preoperatively (n = 24) and postoperatively (n = 15) after bilateral implantation of monofocal intraocular lenses (IOLs). The degree of cataract was evaluated objectively with the objective scatter index (OSI). Visual acuity (VA) and perceived visual quality of natural scene images (Multifocal Acceptance Score) were measured before and after cataract surgery at far (4 m), intermediate (64 cm) and near distance (40 cm) with 4 binocular presbyopic corrections (single vision, bifocal, monovision and modified-monovision) simulated with a binocular Simultaneous Vision simulator based on temporal multiplexing. RESULTS VA was significantly correlated with OSI ( r = -0.71, P < .0005), although the visual degradation at far for each correction was constant and not correlated with OSI. The visual benefit at near distance provided by the presbyopic correction was noticeable (23.3% ± 27.6% across corrections) for OSI <5. The individual perceptual scores were highly correlated preoperatively vs postoperatively ( r = 0.64, P < .0005) for all corrections and distances. CONCLUSIONS Visual simulations of IOLs are an excellent tool to explore prospective postoperative vision. The high correlation in the perceptual scores pre- and post-cataract surgery demonstrates that SimVis Gekko can be used in cataractous patients to guide the selection of the optimal correction for a patient.
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Affiliation(s)
- Xoana Barcala
- From the Institute of Optics, Spanish National Research Council, IO-CSIC, Madrid, Spain (Barcala, Zaytouny, Dorronsoro, Marcos); 2EyesVision SL, Madrid, Spain (Barcala, Dorronsoro); Servicio de Oftalmología, Hospital Clinico San Carlos, Universidad Complutense de Madrid, Spain (Rego-Lorca, Sanchez-Quiros, Sanchez-Jean, Martinez-de-la-Casa); Center for Visual Science, The Institute of Optics, Flaum Eye Institute, University of Rochester, Rochester, New York (Marcos)
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5
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Emmerich L, Ohlendorf A, Leube A, Suchkov N, Wahl S. Development and Testing of a Compact Autorefractor Based on Double-Pass Imaging. SENSORS (BASEL, SWITZERLAND) 2022; 23:362. [PMID: 36616960 PMCID: PMC9823743 DOI: 10.3390/s23010362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/05/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
Autorefraction is an objective way to determine the refractive error of the eye, without the need for feedback by the patient or a well-educated practitioner. To make refractive measurements more accessible in the background of the growing prevalence of myopia, a compact autorefractor was built, containing only few optical components and relying on double-pass imaging and the physical properties of the point-spread function and digital image processing instead. A method was developed to analyze spherical defocus as well as the defocus and angle of astigmatism. The device was tested using calibrator eye models in a range of ± 15 D spherical defocus and -3 D astigmatic defocus. Reliable results could be achieved across the whole measurement range, with only a small increase in deviation toward high values of refractive errors, showing the feasibility of a PSF-based approach for a compact and low-cost solution for objective measurements of refractive error.
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Affiliation(s)
- Linus Emmerich
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
| | - Arne Ohlendorf
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
- Carl Zeiss Vision International GmbH, Turnstr. 27, 73430 Aalen, Germany
| | - Alexander Leube
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
- Carl Zeiss Vision International GmbH, Turnstr. 27, 73430 Aalen, Germany
| | - Nikolai Suchkov
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
| | - Siegfried Wahl
- Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Str. 7, 72076 Tuebingen, Germany
- Carl Zeiss Vision International GmbH, Turnstr. 27, 73430 Aalen, Germany
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6
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Kanematsu T, Koida K. Influence of Stimulus Size on Simultaneous Chromatic Induction. Front Psychol 2022; 13:818149. [PMID: 35140670 PMCID: PMC8818722 DOI: 10.3389/fpsyg.2022.818149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/03/2022] [Indexed: 11/30/2022] Open
Abstract
Chromatic induction is a major contextual effect of color appearance. Patterned backgrounds are known to induce strong chromatic induction effects. However, it has not been clarified whether the spatial extent of the chromatic surrounding induces a chromatic contrast or assimilation effects. In this study, we examined the influence of the width of a center line and its flanking white contour on the color appearance when the line was surrounded by chromatic backgrounds. A strong color shift was observed when the center line was flanked by white contours with the L/M- and S-cone chromatic backgrounds. There was a difference between the optimal widths of the center line and the contour for the shift in color appearance for the L/M-cone chromaticity (0.9 and 1.1–1.7 min, respectively) and the S-cone chromaticity (8.2–17.5 and 0.9–2.5 min, respectively). The optimal width of the center line for the L/M-cone was finer than the resolution-limit width of the chromatic contrast sensitivity and coarser than that of the luminance contrast sensitivity. Thus, the color appearance of the center line could be obtained by integrating broad chromatic information and fine luminance details. Due to blurring and chromatic aberrations, the simulated artifact was large for the darker center line and S-cone background, thus suggesting that the artifact could explain the luminance dependency of the induction along the S-cone chromaticity. Moreover, the findings of this study reveal that the dominant factor of the color shift is neural instead of optical.
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Affiliation(s)
- Tama Kanematsu
- Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kowa Koida
- Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Japan
- Electronics-Inspired Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, Toyohashi, Japan
- *Correspondence: Kowa Koida,
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Sánchez RF, García-Guerra CE, Martínez-Roda JA, de Paul AG, Issolio LA, Pujol J. Implementation of the Frequency Scatter Index in Clinical Commercially Available Double-pass Systems. Curr Eye Res 2021; 47:391-398. [PMID: 34738850 DOI: 10.1080/02713683.2021.2002908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
A previous work has reported a methodology to quantify intraocular scattering using a high sensitivity double-pass instrument with a robust index, the frequency scatter index. The purpose of our study was to evaluate an adaptation of the frequency scatter index for use in clinical double-pass systems. A prospective observational study was carried out in a group of patients with nuclear cataracts (n = 52) and in a control group (n = 11) using conventional double-pass systems. The frequency scatter index and the objective scatter index were used to assess the scattering. The Spearman coefficient was calculated to assess the correlation between both indexes, obtained from the double-pass images. Simultaneous measurements were performed with a double-pass and with a Hartmann-Shack wavefront sensor in the control group. The root-mean-square wavefront error and the full width at half maximum of the double-pass image were used to quantify the residual aberrations introduced by the variations in pupil size and retinal eccentricity. Measurement in eyes with different grades of cataracts shows a strong correlation (ρ = 0.929, p < .0001) between the frequency scatter index and the objective scatter index. A certain degree of correlation was observed between the objective scatter index and the root-mean-square and between the objective scatter index and the full width at half maximum, both for measurements with a different pupillary diameter and with a different retinal eccentricity (p < .05). No relationship was observed between the frequency scatter index and the root-mean-square or between the frequency scatter index and the full width at half maximum (p > .05). We have introduced and evaluated an adaptation of a methodology proposed recently for the measurement of intraocular scattering using the double-pass technique with a robust index, which is less affected by ocular aberrations. The frequency scatter index can be applied to conventional double-pass instruments available in clinical environments.
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Affiliation(s)
- Roberto F Sánchez
- Instituto de Investigación en Luz, Ambiente y Visión, CONICET-UNT, Tucumán, Argentina
| | - Carlos E García-Guerra
- Centre de Desenvolupament de Sensors, Instrumentació i Sistemes, Universitat Politecnica de Catalunya, Barcelona, España
| | - Joan A Martínez-Roda
- Centre de Desenvolupament de Sensors, Instrumentació i Sistemes, Universitat Politecnica de Catalunya, Barcelona, España
| | - Aníbal G de Paul
- Instituto de Investigación en Luz, Ambiente y Visión, CONICET-UNT, Tucumán, Argentina
| | - Luis A Issolio
- Instituto de Investigación en Luz, Ambiente y Visión, CONICET-UNT, Tucumán, Argentina.,Departamento de Luminotecnia, Luz y Visión, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Jaume Pujol
- Centre de Desenvolupament de Sensors, Instrumentació i Sistemes, Universitat Politecnica de Catalunya, Barcelona, España
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8
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Tomás J, Piñero DP, Alió JL. Intra‐observer repeatability of optical quality measures provided by a double‐pass system. Clin Exp Optom 2021; 95:60-5. [DOI: 10.1111/j.1444-0938.2011.00660.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Javier Tomás
- Vissum/Instituto Oftalmológico de Alicante, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - Jorge L Alió
- Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain. E‐mail:
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9
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Lombardo M, Lombardo G. New methods and techniques for sensing the wave aberrations of human eyes. Clin Exp Optom 2021; 92:176-86. [DOI: 10.1111/j.1444-0938.2009.00356.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Marco Lombardo
- Vision Engineering, Reggio Calabria, Italy and CNR‐INFM LiCryL Laboratory, Department of Physics, University of Calabria, Rende (CS), Italy
E‐mail:
| | - Giuseppe Lombardo
- Vision Engineering, Reggio Calabria, Italy and CNR‐INFM LiCryL Laboratory, Department of Physics, University of Calabria, Rende (CS), Italy
E‐mail:
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10
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Jamali A, Bryant D, Bhowmick AK, Bos PJ. Large area liquid crystal lenses for correction of presbyopia. OPTICS EXPRESS 2020; 28:33982-33993. [PMID: 33182876 DOI: 10.1364/oe.408770] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Presbyopia is the failure of the eye lens to accommodate. The widely used presbyopia correction method involves wearing bi/trifocal or progressive glasses, which limits the field of view due to division of lens area into sections of different optical power. A large aperture focus tunable liquid crystal lens has the potential to correct human eye accommodation failure and provide a wide field of view. In this paper, we present characterization and demonstration of a segmented phase profile liquid crystal lens, which has the characteristics of a large area (diameter: 20 mm), being flat and thin (<2 mm), and having continuous focus tunability (1.5 D to 0 D), fast response time (<500 ms), low operating voltage (<5 V), and on-axis diffraction-limited performance (for a 5mm aperture). Considering all these properties, our lens provides performance details of an approach for presbyopia correction. We have tested the minimum resolution and visual acuity of 20 subjects using the designed lens and compared the results with a reference glass lens of the same optical power.
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11
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Martínez‐Roda JA, García‐Guerra CE, Diaz‐Doutón F, Pujol J, Salvador A, Vilaseca M. Quantification of forward scattering based on the analysis of double-pass images in the frequency domain. Acta Ophthalmol 2019; 97:e1019-e1026. [PMID: 31050166 PMCID: PMC6849746 DOI: 10.1111/aos.14122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 03/28/2019] [Indexed: 11/26/2022]
Abstract
Purpose To assess forward intraocular scattering by means of a new parameter (Frequency Scatter Index, FSI3) based on the analysing double‐pass retinal images in the frequency domain, which minimizes the impact of aberrations on the results. Methods A prospective observational study was carried out in the Department of Ophthalmology, Hospital Universitari Mútua de Terrassa (Spain) on a group of 19 patients diagnosed with nuclear cataracts of various LOCSIII grades and a control group (CG) with nine healthy eyes. We recorded double‐pass retinal images with a custom set‐up based on a high‐sensitivity digital camera. The FSI3 was then computed using spatial frequencies below three cycles per degree. A preliminary validation of the FSI3 was performed on an artificial eye and two eyes of volunteers with and without commercial diffusers, and under defocus. Results The FSI3 was hardly affected by defocus values up to 2.50 D. The mean (and standard deviation) FSI3 values were as follows: for the CG, 1.19 (0.21); and for LOCSIII grades nuclear opacity 1, 2 and 3, 1.30 (0.12), 1.62 (0.21) and 1.85 (0.21), respectively. Eyes with cataracts showed FSI3 values significantly different than healthy eyes (p = 0.001). A good correlation (ρ = 0.861, p < 0.001) was found between the FSI3 and objective scatter index provided by a commercial instrument. Conclusion Since aberrations have little impact on the FSI3, the light scatter assessment becomes less dependent on the patient's refractive error compensation and the presence of higher‐order aberrations. The FSI3 can further the clinical and scientific understanding of forward intraocular scattering.
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Affiliation(s)
- Joan A. Martínez‐Roda
- Centre for Sensors, Instruments and Systems Development (CD6) Universitat Politècnica de Catalunya (UPC) Terrassa Spain
| | - Carlos E. García‐Guerra
- Centre for Sensors, Instruments and Systems Development (CD6) Universitat Politècnica de Catalunya (UPC) Terrassa Spain
| | - Fernando Diaz‐Doutón
- Centre for Sensors, Instruments and Systems Development (CD6) Universitat Politècnica de Catalunya (UPC) Terrassa Spain
| | - Jaume Pujol
- Centre for Sensors, Instruments and Systems Development (CD6) Universitat Politècnica de Catalunya (UPC) Terrassa Spain
| | - Antoni Salvador
- Ophthalmology Service Hospital Universitari Mútua de Terrassa Terrassa Spain
| | - Meritxell Vilaseca
- Centre for Sensors, Instruments and Systems Development (CD6) Universitat Politècnica de Catalunya (UPC) Terrassa Spain
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12
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Cottaris NP, Jiang H, Ding X, Wandell BA, Brainard DH. A computational-observer model of spatial contrast sensitivity: Effects of wave-front-based optics, cone-mosaic structure, and inference engine. J Vis 2019; 19:8. [PMID: 30943530 DOI: 10.1167/19.4.8] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We present a computational-observer model of the human spatial contrast-sensitivity function based on the Image Systems Engineering Toolbox for Biology (ISETBio) simulation framework. We demonstrate that ISETBio-derived contrast-sensitivity functions agree well with ones derived using traditional ideal-observer approaches, when the mosaic, optics, and inference engine are matched. Further simulations extend earlier work by considering more realistic cone mosaics, more recent measurements of human physiological optics, and the effect of varying the inference engine used to link visual representations to psychophysical performance. Relative to earlier calculations, our simulations show that the spatial structure of realistic cone mosaics reduces the upper bounds on performance at low spatial frequencies, whereas realistic optics derived from modern wave-front measurements lead to increased upper bounds at high spatial frequencies. Finally, we demonstrate that the type of inference engine used has a substantial effect on the absolute level of predicted performance. Indeed, the performance gap between an ideal observer with exact knowledge of the relevant signals and human observers is greatly reduced when the inference engine has to learn aspects of the visual task. ISETBio-derived estimates of stimulus representations at various stages along the visual pathway provide a powerful tool for computing the limits of human performance.
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Affiliation(s)
- Nicolas P Cottaris
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Haomiao Jiang
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Xiaomao Ding
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian A Wandell
- Department of Psychology, Stanford University, Stanford, CA, USA
| | - David H Brainard
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
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13
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García-Guerra CE, Martínez-Roda JA, Aldaba M, Díaz-Doutón F, Vilaseca M, Vohnsen B, Pujol J. Method to reduce undesired multiple fundus scattering effects in double-pass systems. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:918-924. [PMID: 31045021 DOI: 10.1364/josaa.36.000918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
Double-pass systems rely on backscattering of light by the human ocular fundus to assess the optical quality of the eye. In this work, we present a method to reduce double-pass image degradation caused by undesired multiple scattering effects in the eye fundus. The reduction is based on combined data processing of simultaneous measurements using two different configurations: one symmetric with equal entrance and exit pupils and another asymmetric with unequal entrance and exit pupils. Under certain conditions, such scattering effects may be effectively suppressed. Measurements of human eyes show that, although multiple fundus scattering imposes a shift on the estimations, double-pass systems can be used to predict the optical quality of the eye within a population.
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14
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Cerda-Company X, Otazu X, Sallent N, Parraga CA. The effect of luminance differences on color assimilation. J Vis 2018; 18:10. [PMID: 30347096 DOI: 10.1167/18.11.10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The color appearance of a surface depends on the color of its surroundings (inducers). When the perceived color shifts towards that of the surroundings, the effect is called "color assimilation" and when it shifts away from the surroundings it is called "color contrast." There is also evidence that the phenomenon depends on the spatial configuration of the inducer, e.g., uniform surrounds tend to induce color contrast and striped surrounds tend to induce color assimilation. However, previous work found that striped surrounds under certain conditions do not induce color assimilation but induce color contrast (or do not induce anything at all), suggesting that luminance differences and high spatial frequencies could be key factors in color assimilation. Here we present a new psychophysical study of color assimilation where we assessed the contribution of luminance differences (between the target and its surround) present in striped stimuli. Our results show that luminance differences are key factors in color assimilation for stimuli varying along the s axis of MacLeod-Boynton color space, but not for stimuli varying along the l axis. This asymmetry suggests that koniocellular neural mechanisms responsible for color assimilation only contribute when there is a luminance difference, supporting the idea that mutual-inhibition has a major role in color induction.
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Affiliation(s)
- Xim Cerda-Company
- Computer Vision Center, Computer Science Department, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Xavier Otazu
- Computer Vision Center, Computer Science Department, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Nilai Sallent
- Computer Vision Center, Computer Science Department, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - C Alejandro Parraga
- Computer Vision Center, Computer Science Department, Universitat Autonoma de Barcelona, Barcelona, Spain
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15
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Martínez-Roda JA, Vilaseca M, Ondategui JC, Almudí L, Asaad M, Mateos-Pena L, Arjona M, Pujol J. Double-pass technique and compensation-comparison method in eyes with cataract. J Cataract Refract Surg 2018; 42:1461-1469. [PMID: 27839601 DOI: 10.1016/j.jcrs.2016.08.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 07/26/2016] [Accepted: 08/05/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE To clinically assess the objective scatter index (OSI) obtained from double-pass images and the log(s) parameter measured with the direct compensation-comparison psychophysical technique in eyes with cataract. SETTING Ophthalmology Service, Terrassa Hospital, Barcelona, Spain. DESIGN Prospective observational case series. METHODS The analysis comprised eyes diagnosed with nuclear, cortical, or posterior subcapsular cataracts and healthy eyes (control group). Patient examinations included assessment of the manifest subjective refraction, corrected distance visual acuity, contrast sensitivity, and cataract grade using the Lens Opacities Classification System III (LOCS III) score. The protocol also included the straylight (log[s]) measured by the C-Quant device, measurement of the objective optical quality (Strehl ratio and modulation transfer function cutoff frequency), and the OSI (HD Analyzer). RESULTS Significant correlations with LOCS III classification were found in terms of log(s) and OSI, although they were slightly stronger with OSI for all cataract types, which could be attributable to higher-order aberrations. The OSI and log(s) shared approximately 44% of the scattering estimation and to coincide on the visual function decline with scattering for the 3 cataract types evaluated. Limits to discriminate between healthy and cataractous eyes and sensitivity and specificity values were 1.15 (sensitivity 91%, specificity 100%) for log(s) and 1.18 (sensitivity 89%, specificity 100%) for OSI (P < .05). CONCLUSIONS Both instruments provide complementary information to diagnose cataracts and follow patients. Although backscattered light from deeper retinal layers can have an effect on OSI, the double-pass image provides information to grade different types of cataract when assessing cataractous eyes for treatment. FINANCIAL DISCLOSURE None of the authors has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Juan A Martínez-Roda
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain.
| | - Meritxell Vilaseca
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Juan C Ondategui
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Lorena Almudí
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Moafak Asaad
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Lorena Mateos-Pena
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Montserrat Arjona
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
| | - Jaume Pujol
- From the University Vision Centre (Martínez-Roda, Ondategui, Mateos-Pena), Department of Optics and Optometry, and the Centre for Sensors, Instruments and Systems Development (Vilaseca, Arjona, Pujol), Universitat Politècnica de Catalunya, and the Ophthalmology Service (Almudí, Asaad), Hospital de Terrassa, Terrassa, Barcelona, Spain
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Hamoudi H, Correll Christensen U, La Cour M. Epiretinal membrane surgery: an analysis of 2-step sequential- or combined phacovitrectomy surgery on refraction and macular anatomy in a prospective trial. Acta Ophthalmol 2018; 96:243-250. [PMID: 28926197 DOI: 10.1111/aos.13572] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/30/2017] [Indexed: 11/30/2022]
Abstract
PURPOSE To assess the impact of combined phacoemulsification-vitrectomy and sequential surgery for idiopathic epiretinal membrane (ERM) on refractive error (RE) and macular morphology. METHODS In this prospective clinical trial, we allocated phakic eyes with ERM to (1) cataract surgery and subsequent pars plana vitrectomy (PPV) (CAT group), (2) PPV and subsequent cataract surgery (VIT group) or (3) phaco-vitrectomy (COMBI group). Examinations were at baseline, one month after each surgery, and at 3 months and 12 months of follow-up. Primary outcome was the RE (the difference between predicted and achieved spherical equivalent); secondary outcomes were best-corrected visual acuity (BCVA), and incidence of cystoid macular oedema (CME) defined as >10% increment of central subfield macular thickness (CSMT). RESULTS Sixty-two eyes were enrolled. The mean RE showed a small myopic shift of -0.36D in all groups 1 month after surgery, decreasing after 12 months to -0.17D. The absolute value of the RE (ARE) ranged 0.49-0.68D after 12 months. In the immediate postoperative period, there was a higher incidence of CME in the CAT group. There was no significant difference in final RE, ARE, BCVA and CSMT between the groups. Four cases (17%) in the CAT group had resolved visual complaints and improved BCVA after cataract surgery resulting in no need for PPV within the follow-up period. CONCLUSION Surgery for idiopathic ERM in phakic eyes with either phaco-vitrectomy or sequential surgery are equal approaches with respect to functional- (RE, BCVA) and anatomical outcomes (CME, CSMT). However, if starting with cataract surgery, 17% of the cases may not need subsequent PPV.
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Affiliation(s)
- Hassan Hamoudi
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen University Hospital; Glostrup Denmark
| | - Ulrik Correll Christensen
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen University Hospital; Glostrup Denmark
| | - Morten La Cour
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen University Hospital; Glostrup Denmark
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Hamoudi H. Epiretinal membrane surgery: an analysis of sequential or combined surgery on refraction, macular anatomy and corneal endothelium. Acta Ophthalmol 2018. [DOI: 10.1111/aos.13690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hassan Hamoudi
- Department of Ophthalmology; Rigshospitalet-Glostrup; Copenhagen University Hospital; Glostrup Denmark
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Kobashi H, Kamiya K, Shimizu K. Impact of Forward and Backward Scattering and Corneal Higher-Order Aberrations on Visual Acuity after Penetrating Keratoplasty. Semin Ophthalmol 2018; 33:748-756. [PMID: 29336641 DOI: 10.1080/08820538.2018.1427767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To assess the relationship of forward and backward scattering and corneal higher-order aberrations (HOAs) with corrected distance visual acuity (CDVA) after penetrating keratoplasty (PK). METHODS This retrospective study comprised 25 eyes of 25 consecutive patients who underwent PK using the VisuMax femtosecond laser system and age-matched 25 eyes of 25 healthy subjects. We quantitatively assessed objective scattering index (OSI) using the double-pass instrument (OQAS II, Visiometrics), corneal densitometry (CD) and corneal HOAs with the Scheimpflug rotating camera (Pentacam HR, Oculus) 1 year postoperatively. RESULTS The OSI, CD, and corneal HOAs were significantly larger in the PK group than those in the control group (p ≤ 0.011). We found significant correlations of logMAR CDVA with the OSI (r = 0.477, p = 0.016), and with the anterior, posterior, and total corneal HOAs of the central 4-mm zone (anterior: r = 0.573, p = 0.003, posterior: r = 0.596, p = 0.002, total: r = 0.472, p = 0.017), but no significant association with the CD of the 0-2 mm zone at any layers (anterior: r = 0.236, p = 0.257, center: r = 0.139, p = 0.506, posterior: r = 0.073, p = 0.728, total: r = 0.212, p = 0.308). Similar results were obtained when the analysis was repeated with corneal HOAs of the central 6-mm zone and CDs in 2-6 mm zone. CONCLUSIONS Our pilot study demonstrated that the postoperative CDVA was significantly correlated with OSI and corneal HOAs, but not with backward scattering in post-PK eyes, suggesting that OSI as well as corneal HOAs plays an essential role in postoperative visual performance after PK.
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Affiliation(s)
- Hidenaga Kobashi
- a Department of Ophthalmology , University of Kitasato School of Medicine , Kanagawa , Japan.,b Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School , Schepens Eye Research Institute , Boston , MA , USA
| | - Kazutaka Kamiya
- a Department of Ophthalmology , University of Kitasato School of Medicine , Kanagawa , Japan
| | - Kimiya Shimizu
- a Department of Ophthalmology , University of Kitasato School of Medicine , Kanagawa , Japan
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Post-operative Refractive Prediction Error After Phacovitrectomy: A Retrospective Study. Ophthalmol Ther 2017; 7:83-94. [PMID: 29236212 PMCID: PMC5997604 DOI: 10.1007/s40123-017-0116-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Indexed: 12/12/2022] Open
Abstract
Introduction Many authors have reported on a myopic post-operative refractive prediction error when combining phacoemulsification with pars plana vitrectomy (phacovitrectomy). In this study we evaluate the amount of this error in our facility and try to elucidate the various factors involved. Methods This was a retrospective study which included 140 patients who underwent phacovitrectomy (39 with macular holes, 88 with puckers, and 13 with floaters). Post-operative refractive error was defined as the difference between the actual spherical equivalent (SEQ) and expected SEQ based on the SRK/T and Holladay-II formulas. Both univariate (paired t test, independent t test, one-way analysis of variance, or Mann–Whitney test) and multivariate (regression analysis) statistical analyses were performed. Results Overall, a refractive error of − 0.13 dpt (p = 0.033) and − 0.26 dpt (p < 0.01) were found in the SRK/T and Holladay-II formulas, respectively. For the independent diagnoses, only macular holes showed a myopic error with the SRK/T (− 0.31 dpt; p < 0.01) and Holladay-II (− 0.44 dpt; p < 0.01) formulas. In univariate analysis, significant factors involved in myopic refractive error were macular hole as diagnosis (p < 0.01 for SRK/T and Holladay-II), gas tamponade (SRK/T p = 0.024; Holladay-II p = 0.025), pre-operative myopia (p < 0.01 for SRK/T), and optical technique for axial length measurement (SRK/T and Holladay-II p < 0.01). In the multivariate analysis, pre-operative axial length (p = 0.026), optical technique for axial length measurement (p < 0.01), and pre-operative SEQ (p < 0.01) were independent predictors for myopic refractive error in the SRK/T formula. For the Holladay-II formula, optical technique for axial length measurement (p < 0.01) and pre-operative SEQ (p = 0.04) were predictive. Conclusion Various factors are involved in determining the myopic refractive error after phacovitrectomy. Not every factor seems to be as important in each individual patient, suggesting a more tailored approach is warranted to overcome this problem.
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Wagenfeld L, Hermsdorf K, Stemplewitz B, Druchkiv V, Frings A. Refractive predictability in eyes with intraocular gas tamponade - results of a prospective controlled clinical trial. Clin Ophthalmol 2017; 11:993-998. [PMID: 28579750 PMCID: PMC5449115 DOI: 10.2147/opth.s132644] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose To determine the postoperative refractive error in eyes with intraocular gas tamponade in combined phacovitrectomy using a Z-haptic intraocular lens (IOL). Methods This prospective non-randomized case-control study compared patients with combined phacovitrectomy with or without intraocular gas tamponade to cataract surgery-only. The main outcome measure was the IOL power prediction error (PE). Secondary outcome measures were spherical equivalent, anterior chamber depth (ACD), and axial length. Results Thirty-four patients with epiretinal membranes and 18 patients with cataract only were enrolled. There were no statistically significant (P>0.05) differences of IOL power PE or postoperative ACDs (P=0.952–1.00). Nevertheless, IOL power PE indicated a myopic shift in cases with phacovitrectomy independent of gas tamponade (P=1.00). No statistically significant between-group differences between secondary outcome measures were observed. Conclusion A myopic shift after phacovitrectomy seems to be independent of the use of intraocular gas tamponade. When using a Z-haptic IOL, aiming for slight residual hyperopia (+0.50 D) is suggested in patients having phacovitrectomy.
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Affiliation(s)
- Lars Wagenfeld
- Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg
| | - Kristin Hermsdorf
- Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg
| | - Birthe Stemplewitz
- Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg
| | - Vasyl Druchkiv
- Department of Ophthalmology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg
| | - Andreas Frings
- Department of Ophthalmology, University Hospital Düsseldorf, Heinrich-Heine University, Düsseldorf, Germany
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García-Guerra CE, Aldaba M, Arjona M, Díaz-Doutón F, Martínez-Roda JA, Pujol J. Response for light scattered in the ocular fundus from double-pass and Hartmann-Shack estimations. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2016; 33:2150-2157. [PMID: 27857440 DOI: 10.1364/josaa.33.002150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Double-pass (DP) and Hartmann-Shack (HS) are complementary techniques based on reflections of light in the ocular fundus that may be used to estimate the optical properties of the human eye. Under conventional data processing, both of these assessment modes provide information on aberrations. In addition, DP data contain the effects of scattering. In the ocular fundus, this phenomenon may arise from the interaction of light with not only the retina, but also deeper layers up to which certain wavelengths may penetrate. In this work, we estimate the response of the ocular fundus to incident light by fitting the deviations between DP and HS estimations using an exponential model. In measurements with negligible intraocular scattering, such differences may be related to the lateral spreading of light that occurs in the ocular fundus due to the diffusive properties of the media at the working wavelength. The proposed model was applied in young healthy eyes to evaluate the performance of scattering in such a population. Besides giving a parameter with information on the ocular fundus, the model contributes to the understanding of the differences between DP and HS estimations.
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Vinas M, Dorronsoro C, Garzón N, Poyales F, Marcos S. In vivo subjective and objective longitudinal chromatic aberration after bilateral implantation of the same design of hydrophobic and hydrophilic intraocular lenses. J Cataract Refract Surg 2016; 41:2115-24. [PMID: 26703287 DOI: 10.1016/j.jcrs.2015.11.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/30/2015] [Accepted: 03/31/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE To measure the longitudinal chromatic aberration in vivo using psychophysical and wavefront-sensing methods in patients with bilateral implantation of monofocal intraocular lenses (IOLs) of similar aspheric design but different materials (hydrophobic Podeye and hydrophilic Poday). SETTING Instituto de Optica, Consejo Superior de Investigaciones Cientificas, Madrid, Spain. DESIGN Prospective observational study. METHODS Measurements were performed with the use of psychophysical (480 to 700 nm) and wavefront-sensing (480 to 950 nm) methods using a custom-developed adaptive optics system. Chromatic difference-of-focus curves were obtained from best-focus data at each wavelength, and the longitudinal chromatic aberration was obtained from the slope of linear regressions to those curves. RESULTS The longitudinal chromatic aberration from psychophysical measurements was 1.37 diopters (D) ± 0.08 (SD) (hydrophobic) and 1.21 ± 0.08 D (hydrophilic). From wavefront-sensing, the longitudinal chromatic aberration was 0.88 ± 0.07 D and 0.73 ± 0.09 D, respectively. At 480 to 950 nm, the longitudinal chromatic aberration was 1.27 ± 0.09 D (hydrophobic) and 1.02 ± 0.13 D (hydrophilic). The longitudinal chromatic aberration was consistently higher in eyes with the hydrophobic IOL than in eyes with the hydrophilic IOL (a difference of 0.16 D and 0.15 D, respectively). Similar to findings in young phakic eyes, the longitudinal chromatic aberration from the psychophysical method was consistently higher than from wavefront-sensing, by 0.48 D (35.41%) for the hydrophobic IOL and 0.48 D (39.43%) for the hydrophilic IOL. CONCLUSION Longitudinal chromatic aberrations were smaller with hydrophilic IOLs than with hydrophobic IOLs of the same design. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Maria Vinas
- From the Instituto de Óptica (Vinas, Dorronsoro, Marcos), Consejo Superior de Investigaciones Científicas, and the Instituto de Oftalmología Avanzada (Garzón, Poyales), Madrid, Spain.
| | - Carlos Dorronsoro
- From the Instituto de Óptica (Vinas, Dorronsoro, Marcos), Consejo Superior de Investigaciones Científicas, and the Instituto de Oftalmología Avanzada (Garzón, Poyales), Madrid, Spain
| | - Nuria Garzón
- From the Instituto de Óptica (Vinas, Dorronsoro, Marcos), Consejo Superior de Investigaciones Científicas, and the Instituto de Oftalmología Avanzada (Garzón, Poyales), Madrid, Spain
| | - Francisco Poyales
- From the Instituto de Óptica (Vinas, Dorronsoro, Marcos), Consejo Superior de Investigaciones Científicas, and the Instituto de Oftalmología Avanzada (Garzón, Poyales), Madrid, Spain
| | - Susana Marcos
- From the Instituto de Óptica (Vinas, Dorronsoro, Marcos), Consejo Superior de Investigaciones Científicas, and the Instituto de Oftalmología Avanzada (Garzón, Poyales), Madrid, Spain
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Schramm S, Schikowski P, Lerm E, Kaeding A, Haueisen J, Baumgarten D. Shack-Hartmann-based objective straylight assessment of the human eye in an increased scattering angle range. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:76003. [PMID: 27380449 DOI: 10.1117/1.jbo.21.7.076003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
Objective measurement of straylight in the human eye with a Shack–Hartmann (SH) wavefront aberrometer is limited in imaging angle. We propose a measurement principle and a point spread function (PSF) reconstruction algorithm to overcome this limitation. In our optical setup, a variable stop replaces the stop conventionally used to suppress reflections and scatter in SH aberrometers. We record images with 21 diameters of the stop. From each SH image, the average intensity of the pupil is computed and normalized. The intensities represent integral values of the PSF. We reconstruct the PSF, which is the derivative of the intensities with respect to the visual angle. A modified Stiles Holladay approximation is fitted to the reconstructed PSF, resulting in a straylight parameter. A proof-of-principle study was carried out on eight healthy young volunteers. Scatter filters were positioned in front of the volunteers’ eyes to simulate straylight. The straylight parameter was compared to the C-Quant measurements and the filter values. The PSF parameter shows strong correlation with the density of the filters and a linear relation to the C-Quant straylight parameter. Our measurement and reconstruction techniques allow for objective straylight analysis of visual angles up to 4 deg.
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Affiliation(s)
- Stefan Schramm
- Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Department of Computer Science and Automation, Gustav-Kirchhoff-Straße 2, 98693 Ilmenau, Germany
| | | | - Elena Lerm
- Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Department of Computer Science and Automation, Gustav-Kirchhoff-Straße 2, 98693 Ilmenau, Germany
| | - André Kaeding
- GMC Systems mbH, Albert-Einstein-Str. 3, 98693 Ilmenau, Germany
| | - Jens Haueisen
- Technische Universität Ilmenau, Institute of Biomedical Engineering and Informatics, Department of Computer Science and Automation, Gustav-Kirchhoff-Straße 2, 98693 Ilmenau, Germany
| | - Daniel Baumgarten
- University for Health Sciences, Medical Informatics and Technology, Institute of Electrical and Biomedical Engineering, Eduard Wallnöfer-Zentrum 1, Hall in Tirol 6060, Austria
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van der Geest LJ, Siemerink MJ, Mura M, Mourits MP, Lapid-Gortzak R. Refractive outcomes after phacovitrectomy surgery. J Cataract Refract Surg 2016; 42:840-5. [DOI: 10.1016/j.jcrs.2016.03.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 11/29/2022]
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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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Vinas M, Dorronsoro C, Cortes D, Pascual D, Marcos S. Longitudinal chromatic aberration of the human eye in the visible and near infrared from wavefront sensing, double-pass and psychophysics. BIOMEDICAL OPTICS EXPRESS 2015; 6:948-62. [PMID: 25798317 PMCID: PMC4361447 DOI: 10.1364/boe.6.000948] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/03/2015] [Accepted: 02/10/2015] [Indexed: 05/18/2023]
Abstract
Longitudinal Chromatic Aberration (LCA) influences the optical quality of the eye. However, the reported LCA varies across studies, likely associated to differences in the measurement techniques. We present LCA measured in subjects using wavefront sensing, double-pass retinal images, and psychophysical methods with a custom-developed polychromatic Adaptive Optics system in a wide spectral range (450-950 nm), with control of subjects' natural aberrations. LCA measured psychophysically was significantly higher than that from reflectometric techniques (1.51 D vs 1.00 D in the 488-700 nm range). Ours results indicate that the presence of natural aberrations is not the cause for the discrepancies across techniques.
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Frings A, Dulz S, Skevas C, Stemplewitz B, Linke SJ, Richard G, Wagenfeld L. Postoperative refractive error after phacovitrectomy for epiretinal membrane with and without macular oedema. Graefes Arch Clin Exp Ophthalmol 2015; 253:1097-104. [PMID: 25655649 DOI: 10.1007/s00417-015-2948-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/12/2015] [Accepted: 01/21/2015] [Indexed: 11/29/2022] Open
Abstract
PURPOSE This study was initiated to investigate whether the presence of macular oedema influenced intraocular lens (IOL) power calculation in eyes with epiretinal membrane. METHODS The files of patients undergoing combined phacoemulsification were retrospectively reviewed. Two groups were defined according to presence of macular oedema. The main outcome measure was the IOL power prediction error (PE). Secondary outcome measures were the correlation between preoperative macular thickness, absolute change of macular thickness and dioptric shift. The mean postoperative PE achieved with the Haigis formula was compared with the PE that would have been obtained had the SRKII and HofferQ formulas been used. RESULTS We investigated 47 eyes of 47 consecutive patients. Regardless of the IOL formula used, the PE was on average higher in eyes without macula oedema (group 1). The myopic dioptric shift was dependent on preoperative macular thickness and absolute change of macular thickness. This association was more markedly pronounced in group 1. CONCLUSIONS Increased retinal thickness is the main cause for underestimation of the cornea-photoreceptor layer distance, and therefore could contribute to inaccuracy in IOL power calculations. The current results show that a myopic shift tends to be less pronounced in cases where a macula oedema is present. Eyes with pure traction have less predictable refractive results in terms of higher PE and dioptric shift.
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Affiliation(s)
- Andreas Frings
- Department of Ophthalmology, University Medical Center Hamburg-Eppendorf (UKE), Martinistraße 52, 20246, Hamburg, Germany,
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Abstract
The contrast sensitivity function (CSF), a measure of visual sensitivity to a wide range of spatial frequencies, has been widely used as the gain profile of the front-end filter of the visual system to predict how we perceive spatial patterns. However, the CSF itself is determined by the gain profile and other processing inefficiencies of the visual system; it may be problematic to use the CSF as the gain profile in observer models. Here, we applied the external noise paradigm and the perceptual template model (PTM) to characterize several major properties of the visual system. With the external noise normalized gain profile, nonlinearity, and internal additive and multiplicative noises, the PTM accounted for 92.8% of the variance in the experiment data measured in a wide range of conditions and revealed the major processing components that determine the CSF. Unlike the CSF, the external noise normalized gain profile of the visual system is relatively flat across a wide range of spatial frequencies. The results may have major implications for understanding normal and abnormal spatial vision.
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Affiliation(s)
- Fang Hou
- Department of Psychology, The Ohio State University, Columbus, Ohio, USA
| | - Zhong-Lin Lu
- Department of Psychology, Center for Cognitive Brain and Sciences, and Center for Cognitive and Behavioral Brain Imaging, The Ohio State University, Columbus, Ohio, USA
| | - Chang-Bing Huang
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
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Abstract
PURPOSE To determine the accuracy of objective wavefront refractions for predicting subjective refractions for monochromatic infrared light. METHODS Objective refractions were obtained with a commercial wavefront aberrometer (COAS, Wavefront Sciences). Subjective refractions were obtained for 30 subjects with a speckle optometer validated against objective Zernike wavefront refractions on a physical model eye (Teel et al., Design and validation of an infrared Badal optometer for laser speckle, Optom Vis Sci 2008;85:834-42). Both instruments used near-infrared (NIR) radiation (835 nm for COAS, 820 nm for the speckle optometer) to avoid correction for ocular chromatic aberration. A 3-mm artificial pupil was used to reduce complications attributed to higher-order ocular aberrations. For comparison with paraxial (Seidel) and minimum root-mean-square (Zernike) wavefront refractions, objective refractions were also determined for a battery of 29 image quality metrics by computing the correcting lens that optimizes retinal image quality. RESULTS Objective Zernike refractions were more myopic than subjective refractions for 29 of 30 subjects. The population mean discrepancy was -0.26 diopters (D) (SEM = 0.03 D). Paraxial (Seidel) objective refractions tended to be hyperopically biased (mean discrepancy = +0.20 D, SEM = 0.06 D). Refractions based on retinal image quality were myopically biased for 28 of 29 metrics. The mean bias across all 31 measures was -0.24 D (SEM = 0.03). Myopic bias of objective refractions was greater for eyes with brown irises compared with eyes with blue irises. CONCLUSIONS Our experimental results are consistent with the hypothesis that reflected NIR light captured by the aberrometer originates from scattering sources located posterior to the entrance apertures of cone photoreceptors, near the retinal pigment epithelium. The larger myopic bias for brown eyes suggests that a greater fraction of NIR light is reflected from choroidal melanin in brown eyes compared with blue eyes.
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Kubota S. Simulating the human eye in measurements of speckle from laser-based projection displays. APPLIED OPTICS 2014; 53:3814-3820. [PMID: 24921149 DOI: 10.1364/ao.53.003814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/17/2014] [Indexed: 06/03/2023]
Abstract
In quantitative measurement of the speckle observed in laser projection displays, it is essential how accurately one simulates the human eye. Based on the eye model given by Westheimer, we succeeded in simulating the optical transfer function of the eye model using that for the circular aperture. The equivalent circular aperture diameter is dependent on the eye model used in the simulation and its viewing conditions, but particularly for the eye models given by Westheimer and Williams, they substantially agreed, yielding approximately 1.2 mm at green under a 3 mm pupil diameter viewing condition.
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Hamoudi H, Kofod M, La Cour M. Refractive change after vitrectomy for epiretinal membrane in pseudophakic eyes. Acta Ophthalmol 2013; 91:434-6. [PMID: 22998208 DOI: 10.1111/j.1755-3768.2012.02574.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To report the change in refraction in pseudophakic eyes following 23-gauge vitrectomy for epiretinal membrane (ERM), without use of silicone oil, intraocular gas or scleral buckling. METHODS Retrospective review of the records of 28 pseudophakic eyes in 28 patients undergoing 23-gauge pars plana vitrectomy for ERM. All 28 eyes had a measured preoperative refraction in their records and were seen minimum 2 months after vitrectomy for measuring their refraction. Fellow eyes (28 eyes) were used as controls. RESULTS The mean preoperative refraction was -0.15 ± 0.85 dioptre (D), and the mean postoperative refraction was -0.41 ± 0.93 D. Thus, a myopic shift was observed following vitrectomy with a mean change in refraction of -0.26 ± 0.60 D (range +0.75 to -2.13 D, p = 0.032). The postoperative change in refraction was within ±0.25, ±0.50 and ±1.00 D in 39%, 68% and 96% of the eyes, respectively. The mean absolute refractive error was 0.47 ± 0.44 D. The change in refraction in fellow eyes was +0.01 D (p = 0.82). CONCLUSION The change in refraction following 23-gauge pars plana vitrectomy for ERM in pseudophakic eyes was -0.26 D.
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Affiliation(s)
- Hassan Hamoudi
- Department of Ophthalmology, Glostrup Hospital, Copenhagen University Hospital, Glostrup, Denmark
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Hamoudi H, La Cour M. Refractive changes after vitrectomy and phacovitrectomy for macular hole and epiretinal membrane. J Cataract Refract Surg 2013; 39:942-7. [DOI: 10.1016/j.jcrs.2013.04.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 09/24/2012] [Accepted: 09/25/2012] [Indexed: 10/26/2022]
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Watson AB. A formula for the mean human optical modulation transfer function as a function of pupil size. J Vis 2013; 13:18. [DOI: 10.1167/13.6.18] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Bueno JM, Pérez GM. Combined effect of wavelength and polarization in double-pass retinal images in the human eye. Vision Res 2010; 50:2439-44. [PMID: 20833195 DOI: 10.1016/j.visres.2010.09.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 09/02/2010] [Accepted: 09/02/2010] [Indexed: 11/16/2022]
Abstract
A polychromatic double-pass setup was developed to study the effects of wavelength and polarization on retinal image quality. The results show that the central part of the images was similar for all wavelengths (543, 633 and 780 nm) and polarization states. However, the image tails increased significantly when using infrared light for all the polarization states used. For the set of subjects involved in the study, ocular diattenuation presented individual differences, however significant changes were not found across the different wavelengths. Moreover the Stokes vectors providing the maximum intensity transmittance varied across subjects and corresponded to elliptically polarized light. These non-negligible diattenuation effects might affect the performance of clinical devices which only take into account ocular birefringence.
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Affiliation(s)
- Juan M Bueno
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica (CiOyN), Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
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Martínez-Roda JA, Vilaseca M, Ondategui JC, Giner A, Burgos FJ, Cardona G, Pujol J. Optical quality and intraocular scattering in a healthy young population. Clin Exp Optom 2010; 94:223-9. [PMID: 21083759 DOI: 10.1111/j.1444-0938.2010.00535.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND We objectively assessed the optical quality and intraocular scattering by means of parameters provided by a clinical double-pass system in healthy young subjects and thereby we obtained new reference data for clinical diagnosis. We calculated normal values of neural contrast sensitivity function (nCSF) from the measured modulation transfer function (MTF) and the contrast sensitivity function (CSF). METHODS Eligible subjects were healthy adults aged from 18 to 30 years with a logMAR visual acuity (VA) of 0.0 or better and normal values of CSF. Optical quality measurements for a 4.0 mm pupil were performed using the Optical Quality Analysis System (OQAS) based on the double-pass technique. The following parameters were analysed: the modulation transfer function cutoff frequency (MTF(cutoff)), the Strehl(2D) ratio, the OQAS values (OV) at 100, 20 and nine per cent contrasts and the objective scatter index (OSI). RESULTS A total of 178 volunteers responded to the call, of whom 181 eyes were finally part of the study taking into account the criteria for inclusion. The values for the optical quality parameters were: 44.54 ± 7.14 cpd (MTF(cutoff)), 0.27 ± 0.06 (Strehl(2D) ratio), 1.48 ± 0.24 (OV(100%)), 1.58 ± 0.32 (OV(20%)), 1.64 ± 0.39 (OV(9%)), and 0.38 ± 0.19 (OSI). The nCSF calculated was 1.76 ± 0.21 (3 cpd), 2.13 ± 0.23 (6 cpd), 2.01 ± 0.28 (12 cpd) and 1.86 ± 0.33 (18 cpd). CONCLUSION The normal values provided can be a useful tool for discriminating healthy eyes from early abnormal ones in which the optical quality or sensory function is impaired.
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Affiliation(s)
- Joan A Martínez-Roda
- University Vision Centre, Universitat Politècnica de Catalunya, Terrassa, Barcelona, Spain
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Abstract
PURPOSE Seven existing and three new image quality metrics were evaluated in terms of their effectiveness in predicting subjective cycloplegic refraction. METHODS Monochromatic wavefront aberrations (WA) were measured in 70 eyes using a Shack-Hartmann based device (Complete Ophthalmic Analysis System; Wavefront Sciences). Subjective cycloplegic spherocylindrical correction was obtained using a standard manifest refraction procedure. The dioptric amount required to optimize each metric was calculated and compared with the subjective refraction result. Metrics included monochromatic and polychromatic variants, as well as variants taking into consideration the Stiles and Crawford effect (SCE). WA measurements were performed using infrared light and converted to visible before all calculations. RESULTS The mean difference between subjective cycloplegic and WA-derived spherical refraction ranged from 0.17 to 0.36 diopters (D), while paraxial curvature resulted in a difference of 0.68 D. Monochromatic metrics exhibited smaller mean differences between subjective cycloplegic and objective refraction. Consideration of the SCE reduced the standard deviation (SD) of the difference between subjective and objective refraction. CONCLUSIONS All metrics exhibited similar performance in terms of accuracy and precision. We hypothesize that errors pertaining to the conversion between infrared and visible wavelengths rather than calculation method may be the limiting factor in determining objective best focus from near infrared WA measurements.
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39
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Wallis SA, Georgeson MA. Mach edges: Local features predicted by 3rd derivative spatial filtering. Vision Res 2009; 49:1886-93. [DOI: 10.1016/j.visres.2009.04.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Revised: 04/08/2009] [Accepted: 04/29/2009] [Indexed: 10/20/2022]
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van den Berg TJTP, Franssen L, Coppens JE. Straylight in the human eye: testing objectivity and optical character of the psychophysical measurement. Ophthalmic Physiol Opt 2009; 29:345-50. [DOI: 10.1111/j.1475-1313.2009.00638.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Fernández EJ, Artal P. Ocular aberrations up to the infrared range: from 632.8 to 1070 nm. OPTICS EXPRESS 2008; 16:21199-208. [PMID: 19104549 DOI: 10.1364/oe.16.021199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Ocular aberrations were measured by using a Hartmann-Shack wavefront sensor in the visible and infrared portions of the spectrum. In the latter, wavelengths 1030, 1050 and 1070 nm were used for the first time for the study of the optical quality of the eye. In this spectral range the retinal photoreceptors barely respond, so the radiation is virtually invisible for the subject. The results were confronted with those obtained by the same system at 780 and 632.8 nm. Monochromatic aberrations were found to be similar from the visible to the infrared. Longitudinal chromatic aberration was experimentally obtained, being approximately 1 D from 632.8 to 1070 nm. The feasibility of using the infrared for studying the eye was demonstrated. The employment of the infrared has an enormous potential for the better understanding of the impact and influence of the aberrations in vision with adaptive optics. It allows for measuring and controlling aberrations whilst the subject might eventually perform visual tests, with no interference from the beacon light.
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Affiliation(s)
- Enrique J Fernández
- Laboratorio de Optica, Universidad de Murcia, Centro de Investigación en Optica y Nanotecnología, Campus de Espinardo, 30071 Murcia, Spain.
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Logean E, Dalimier E, Dainty C. Measured double-pass intensity point-spread function after adaptive optics correction of ocular aberrations. OPTICS EXPRESS 2008; 16:17348-17357. [PMID: 18958018 DOI: 10.1364/oe.16.017348] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The double-pass intensity point-spread function was recorded in four subjects using a monochromatic source emitting at 543 nm, through a 6.7-mm diameter pupil i) at the fovea after adaptive optics correction of the ocular aberrations, ii) at the fovea without adaptive optics correction, and iii) at 2 degrees of eccentricity with adaptive optics correction. The half-width at half-maximum of the double-pass point-spread function was narrower after correction of the ocular aberrations. At 2 degrees of eccentricity this width was larger than at the fovea. The minimum widths were about 1.1 arcmin in dark pigmented eyes and 1.6 arcmin in light pigmented eyes. These values are 6 to 9 times larger than the width expected from diffraction alone.
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Affiliation(s)
- Eric Logean
- Applied Optics Group, National University of Ireland, Galway, Galway, Ireland.
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Montés-Micó R. Role of the tear film in the optical quality of the human eye. J Cataract Refract Surg 2007; 33:1631-5. [PMID: 17720082 DOI: 10.1016/j.jcrs.2007.06.019] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 06/03/2007] [Indexed: 11/25/2022]
Abstract
This paper reviews recent studies of the role of the tear film in the optical quality of the eye. Recent investigations focus on the dynamics of the tear film after a blink and its important role in the optical quality of the eye. The results in this review were used in an attempt to understand the optical and visual impact of tear-film breakup in normal eyes and dry eyes. It was noted that patients with dry-eye syndrome have large optical aberrations compared with those in normal eyes, which may be the cause of blurry vision associated with the syndrome. In addition, instillation of artificial tears reduces optical aberrations and thus improves the optical quality of vision in these patients.
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Jarvis JR, Wathes CM. On the calculation of optical performance factors from vertebrate spatial contrast sensitivity. Vision Res 2007; 47:2259-71. [PMID: 17588633 DOI: 10.1016/j.visres.2007.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 04/24/2007] [Accepted: 04/24/2007] [Indexed: 10/23/2022]
Abstract
A novel technique for calculating the visual optical modulation transfer function (OMTF) is described. The technique involves application of the Rovamo-Barten model of spatial vision to measured contrast sensitivity data. [For details of the basic model see; Rovamo, J., Mustonen, J., & Nasanen, R. (1994). Modelling contrast sensitivity as a function of retinal illuminance and grating area. Vision Research, 34, 1301-1314 and Barten, P. J. G. (1999). Contrast sensitivity of the human eye and its effects on image quality. Washington: SPIE Optical Engineering Press.] In order to obtain OMTF, the model was simplified for use in the high spatial frequency range and also modified to include a transfer function term relating to attenuation by the retinal receptor sampling process. Calculations of OMTF were initially obtained from published contrast sensitivity for the human, cat, rat and chicken. The results were found to correlate well with OMTF values directly obtained through a double-pass optical measuring technique applied to all four species. It was assumed, following this initial test, that the modified Rovamo-Barten model could be used to extract OMTF from vertebrate contrast sensitivity data in general. Using published behavioural contrast sensitivity, further OMTF values were calculated from the model for the pigeon, goldfish, owl monkey, and tree shrew. The results obtained were used to provide a direct inter-species comparison of optical performance for a matched stimulus luminance. This study also confirms that, in many cases, vertebrate optical and receptor sampling processes are well matched in their attenuation properties.
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Affiliation(s)
- John R Jarvis
- The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, Herts AL9 7TA, UK.
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45
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White BJ, Kerzel D, Gegenfurtner KR. The spatio-temporal tuning of the mechanisms in the control of saccadic eye movements. Vision Res 2006; 46:3886-97. [PMID: 16879855 DOI: 10.1016/j.visres.2006.06.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 06/16/2006] [Accepted: 06/19/2006] [Indexed: 11/24/2022]
Abstract
We compared the spatio-temporal tuning of perception to the mechanisms that drive saccadic eye movements. Detection thresholds were measured for Gabor-targets presented left or right of fixation (4 or 8deg eccentricity), at one of four spatial frequencies (1, 2, 4 or 8cpd) oscillating at one of three temporal frequencies (1, 8 or 16Hz). We then measured saccade latency to each target presented at various multiples of detection threshold. Consistent with previous research, latency decreased as a function of contrast. However, at equal detection performance, we found no systematic difference in saccadic latency and no difference in average oculometric performance (% correct saccade direction) across the different target spatio-temporal frequencies. Furthermore, position error remained fairly constant across all conditions. The results are consistent with the idea that the spatio-temporal signals used for perception are the same as those used by the mechanisms driving saccadic eye movements.
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Affiliation(s)
- Brian J White
- Justus-Liebig-Universität Giessen, Allgemeine Psychologie, Otto-Behaghel-Str. 10F, D-35394 Giessen, Germany.
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Negishi K, Kobayashi K, Ohnuma K, Ohno K, Noda T. Evaluation of Optical Function Using a New Point Spread Function Analysis System in Cataractous and Pseudophakic Eyes: Preliminary Results. Jpn J Ophthalmol 2006; 50:12-9. [PMID: 16453182 DOI: 10.1007/s10384-005-0275-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Accepted: 05/11/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE To evaluate optical function in cataractous and pseudophakic eyes using the new point spread function (PSF) analysis system in a clinical setting. METHODS We applied this new analysis system in the study of two cataractous eyes and one pseudophakic eye of two patients. Using a PSF analyzer, double-pass PSF was measured directly for each subject, and the single-pass modulation transfer function (MTF) and single-pass PSF were calculated. The simulated retinal images of various sizes of Landolt's rings and their contrast characteristics were also calculated by the PSF analyzer. RESULTS The MTF and the contrast of the simulated retinal images degraded in cataractous eyes were compared with data for normal eyes; the degradation pattern depended on the opacification pattern. The MTF and the contrast of the simulated retinal images in the pseudophakic eye improved significantly compared with the cataractous eyes, although both values were lower in the pseudophakic eye than in young normal eyes. CONCLUSIONS Our data showed degradation of optical function in cataractous and pseudophakic eyes in comparison with optical function in young normal eyes. If further accumulations of PSF data are made, it may be possible to establish an objective standard by which to measure the progression of cataract, as well as an objective indication for treatment in the future.
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Affiliation(s)
- Kazuno Negishi
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan.
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Shevell SK, Cao D. Chromatic assimilation measured by temporal nulling. Vision Res 2005; 46:106-16. [PMID: 16095652 DOI: 10.1016/j.visres.2005.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 06/16/2005] [Accepted: 06/17/2005] [Indexed: 11/24/2022]
Abstract
Chromatic assimilation is the shift in color appearance toward nearby light. Assimilation was measured using nearby light with time-varying chromaticity. This light induced time-varying assimilation within the test area. Assimilation was quantified by the amplitude of temporally varying test-area light--in counter-phase to the induced assimilation--required to null the assimilation. Unlike previous studies of assimilation, observers here judged only the steadiness of the test area, not its color. The inducing light was varied in luminance, temporal frequency and chromaticity. The measured assimilation could not be explained by only optical factors affecting receptoral quantal absorption. This implies a neural process contributes to assimilation. The nulling measurements showed also that assimilation was not induced independently within the L/M- and S-cone pathways.
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Affiliation(s)
- Steven K Shevell
- Department of Psychology, University of Chicago, 940 East 57th Street, Chicago, IL 60637, USA.
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Cao D, Shevell SK. Chromatic assimilation: spread light or neural mechanism? Vision Res 2004; 45:1031-45. [PMID: 15695188 DOI: 10.1016/j.visres.2004.10.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Revised: 10/11/2004] [Accepted: 10/15/2004] [Indexed: 11/29/2022]
Abstract
Chromatic assimilation is the shift in color appearance of a test field toward the appearance of nearby light. Possible explanations of chromatic assimilation include wavelength independent spread light, wavelength-dependent chromatic aberration and neural summation. This study evaluated these explanations by measuring chromatic assimilation from a concentric-ring pattern into an equal-energy-white background, as a function of the inducing rings' width, separation, chromaticity and luminance. The measurements showed, in the s direction, that assimilation was observed with different inducing-ring widths and separations when the inducing luminance was lower or higher than the test luminance. In general, the thinner the inducing rings and the smaller their separation, the stronger the assimilation in s. In the l direction, either assimilation or contrast was observed, depending on the ring width, separation and luminance. Overall, the measured assimilation could not be accounted for by the joint contributions from wavelength-independent spread light and wavelength-dependent chromatic aberration. Spatial averaging of neural signals explained the assimilation in s reasonably well, but there were clear deviations from neural spatial averaging for the l direction.
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Affiliation(s)
- Dingcai Cao
- Department of Health Studies, University of Chicago, 940 East 57th Street, Chicago, IL 60637, USA
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Kobayashi K, Shibutani M, Takeuchi G, Ohnuma K, Miyake Y, Negishi K, Ohno K, Noda T. Calculation of ocular single-pass modulation transfer function and retinal image simulation from measurements of the polarized double-pass ocular point spread function. JOURNAL OF BIOMEDICAL OPTICS 2004; 9:154-161. [PMID: 14715068 DOI: 10.1117/1.1627777] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The single-pass modulation transfer function (MTF(sgl)) is an important numerical parameter that can help elucidate the performance and some processes of the human visual system. In previous studies, the MTF(sgl) was calculated from double-pass point spread function (PSF) measurements. These measurements include a depolarized reflection component from the retina that introduces a measurement artifact, and they require long acquisition times to allow averaging to reduce speckle. To solve these problems, we developed a new ocular PSF analysis system (PSFAS) that uses polarization optics to eliminate the depolarized retinal reflection component, and a rotating prism to increase measurement speed. Validation experiments on one patient showed that the MTF(sgl) measured by PSFAS agrees closely with the MTF calculated from contrast sensitivity measurements. A simulated retinal image was calculated by convolution of Landolt rings with the calculated single-pass PSF provided by the PSFAS. The contrast characteristic then was calculated from the simulated retinal images. These results indicate that the MTF(sgl) obtained using the PSFAS may be a reliable measure of visual performance of the optics of the eye, including the optical effects of the retina. The simulated retinal images and contrast characteristics are useful for evaluating visual performance.
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Affiliation(s)
- Katsuhiko Kobayashi
- Topcon Corporation, Research and Development Center, 75-1 Hasunuma-cho, Itabashi-ku, Tokyo 175-8580, Japan.
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Cottaris NP. Artifacts in spatiochromatic stimuli due to variations in preretinal absorption and axial chromatic aberration: implications for color physiology. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2003; 20:1694-1713. [PMID: 12968643 DOI: 10.1364/josaa.20.001694] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The spatiochromatic receptive-field structure of neurons in the macaque visual system has been studied almost exclusively with stimuli based on the human foveal cone fundamentals of Smith and Pokorny [Vision Res. 15, 161 (1975)] and generated on cathode ray tube displays. In the current study the artifacts evoked by cone-isolating, spatially structured stimuli due to variations in the eye's preretinal absorption characteristics and axial chromatic aberration are quantified. In addition, the luminance artifacts evoked by nominally isoluminant sinusoidal grating stimuli due to the same factors are quantified. The results indicate that the spatiochromatic stimuli commonly employed to map receptive fields of neurons at eccentricities > 10 deg are especially prone to artifacts and that these artifacts are maximal for the high-contrast S-cone-isolating stimuli that are often used. On the basis of these simulations, a method is introduced that improves spatiochromatic receptive-field estimates by compensating for response contributions from the incompletely silenced cone mosaics during cone-isolating stimulation.
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Affiliation(s)
- Nicolas P Cottaris
- Group in Vision Science, University of California, Berkeley, Berkeley, California 94720, USA.
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