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Costa MF, Rego LS, Henriques LD, Martins Gaddi C, Souza GS. Reduced eye optical quality contributes to worse chromatic thresholds in aging. Front Integr Neurosci 2023; 17:1129315. [PMID: 37035455 PMCID: PMC10079907 DOI: 10.3389/fnint.2023.1129315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
Purpose Aging causes substantial changes in the intraocular lens, which leads to a reduction in chromatic perception. We aimed to measure the ocular light dispersion component in relation to the reduction in color vision by aging. Methods Intraocular straylight was quantified psychophysically by C-Quant for light dispersion [Log(s)], reliability of the results (ESD), and psychometric sampling quality (Q). The Cambridge Color Test Trivector protocol measured the chromaticity thresholds for protan, deutan, and tritan color confusion axis in CIE 1976 u' v' units. We tested 224 subjects aged 24-68 years (106 men) with normal best-corrected visual acuity and without clinical evidence of cataracts. Results A significant positive correlation was found between ocular dispersion of light and chromaticity thresholds for protan (r = 0.42; p < 0.001), deutan (r = 0.49; p < 0.001) and tritan (r = 0.51; p < 0.0001) color confusion axes with a moderate effect size (η2 = 0.39). However, a weak contribution of the logarithm of the straylight in predicting the chromaticity threshold for protan (b = 0.15; p = 0.025), deutan (b = 0.27; p = 0.001) and tritan (b = 0.21; p = 0.001) color confusion axes was verified in the regression coefficients. The other two measurement quality parameters estimated in the C-Quant were not correlated with chromaticity thresholds, suggesting that there are no problems with the quality of the measurement performed. Conclusion An increase in ocular light dispersion that occurs physiologically with aging negatively impacts the chromaticity threshold in a similar manner across all three color confusion axes. The weak regression effects suggest that neural rather than optical processes were more related to the reduction in chromaticity in aging.
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Affiliation(s)
- Marcelo Fernandes Costa
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, São Paulo, Brazil
- Núcleo de Neurociências Aplicada, University of São Paulo, São Paulo, São Paulo, Brazil
- *Correspondence: Marcelo Fernandes Costa,
| | - Livia Soledade Rego
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Leonardo Dutra Henriques
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Carlo Martins Gaddi
- Department of Experimental Psychology, Institute of Psychology, University of São Paulo, São Paulo, São Paulo, Brazil
- Núcleo de Neurociências Aplicada, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Givago Silva Souza
- Tropical Medicine Center, Federal University of Pará, Belém, Pará, Brazil
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Ankamah E, Green-Gomez M, Roche W, Ng E, Welge-Lüßen U, Kaercher T, Barbur J, Nolan JM. Impact of symptomatic vitreous degeneration on photopic and mesopic contrast thresholds. Clin Exp Optom 2021; 105:609-616. [PMID: 34751082 DOI: 10.1080/08164622.2021.1981116] [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] Open
Abstract
CLINICAL RELEVANCE Contrast thresholds under photopic and mesopic luminance conditions are compromised in subjects with vitreous degeneration. A plausible explanation is needed for the visual discomfort expressed by patients suffering from symptomatic vitreous degeneration. BACKGROUND The current study investigates the effect of symptomatic vitreous degeneration on photopic and mesopic contrast at high spatial frequencies. METHODS An age-matched sample of 115 subjects, comprising 30 subjects with symptomatic vitreous floaters (cases) and 85 healthy subjects (controls), was included in this study. Visual acuity and flicker thresholds were measured for all participants. Photopic and mesopic functional contrast thresholds at 10 cycles per degree were measured for all participants to assess the effect of floaters on contrast. Further, to determine the effect of posterior vitreous detachment on contrast, the sample was divided into three groups: cases with posterior vitreous detachment (n = 12); cases without posterior vitreous detachment (n = 18); and controls (n = 85), and their contrast thresholds were compared. RESULTS Photopic and mesopic contrast thresholds were lower by 37.4% and 27.5%, respectively, when the cases were compared with the controls (p = 0.028 and p < 0.001 for photopic and mesopic contrast thresholds, respectively). Photopic contrast was lower by 64.0% in cases with posterior vitreous detachment compared with controls (p = 0.001). Compared with controls, mesopic contrast was lower in cases with posterior vitreous detachment and in cases without posterior vitreous detachment by 30.3% and 25.6%, respectively (p = 0.014 and p = 0.017 for cases with and without posterior vitreous detachment, respectively). CONCLUSION : Subjects with vitreous degeneration have diminished photopic and mesopic contrast thresholds compared with controls. This finding highlights the negative impact of vitreous degeneration on the quality of vision.
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Affiliation(s)
- Emmanuel Ankamah
- Nutrition Research Centre Ireland, School of Health Science, Waterford Institute of Technology, Co, Waterford, Ireland
| | - Marina Green-Gomez
- Nutrition Research Centre Ireland, School of Health Science, Waterford Institute of Technology, Co, Waterford, Ireland
| | - Warren Roche
- Nutrition Research Centre Ireland, School of Health Science, Waterford Institute of Technology, Co, Waterford, Ireland
| | - Eugene Ng
- Nutrition Research Centre Ireland, School of Health Science, Waterford Institute of Technology, Co, Waterford, Ireland.,Institute of Eye Surgery, UPMC Whitfield Hospital, Co, Waterford, Ireland
| | | | | | - John Barbur
- Applied Vision Research Centre, School of Health Sciences, University of London, London, UK
| | - John M Nolan
- Nutrition Research Centre Ireland, School of Health Science, Waterford Institute of Technology, Co, Waterford, Ireland
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Karaduman A, Karoglu-Eravsar ET, Kaya U, Aydin A, Adams MM, Kafaligonul H. The optomotor response of aging zebrafish reveals a complex relationship between visual motion characteristics and cholinergic system. Neurobiol Aging 2020; 98:21-32. [PMID: 33227566 DOI: 10.1016/j.neurobiolaging.2020.10.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 10/10/2020] [Accepted: 10/17/2020] [Indexed: 12/12/2022]
Abstract
Understanding the principles underlying age-related changes in motion perception is paramount for improving the quality of life and health of older adults. However, the mechanisms underlying age-related alterations in this aspect of vision, which is essential for survival in a dynamic world, still remain unclear. Using optomotor responses to drifting gratings, we investigated age-related changes in motion detection of adult zebrafish (wild-type/AB-strain and achesb55/+ mutants with decreased levels of acetylcholinesterase). Our results pointed out negative optomotor responses that significantly depend on the spatial frequency and contrast level of stimulation, providing supporting evidence for the visual motion-driven aspect of this behavior mainly exhibited by adult zebrafish. Although there were no significant main effects of age and genotype, we found a significant three-way interaction between contrast level, age, and genotype. In the contrast domain, the changes in optomotor responses and thus in the detection of motion direction were age- and genotype-specific. Accordingly, these behavioral findings suggest a strong but complicated relationship between visual motion characteristics and the cholinergic system during neural aging.
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Affiliation(s)
- Aysenur Karaduman
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; Interdisciplinary Neuroscience Program, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics Zebrafish Facility, Bilkent University, Ankara, Turkey
| | - Elif Tugce Karoglu-Eravsar
- Interdisciplinary Neuroscience Program, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics Zebrafish Facility, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey
| | - Utku Kaya
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Alaz Aydin
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
| | - Michelle M Adams
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; Interdisciplinary Neuroscience Program, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics Zebrafish Facility, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey; Department of Psychology, Bilkent University, Ankara, Turkey
| | - Hulusi Kafaligonul
- National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey; Interdisciplinary Neuroscience Program, Aysel Sabuncu Brain Research Center, Bilkent University, Ankara, Turkey; Department of Molecular Biology and Genetics Zebrafish Facility, Bilkent University, Ankara, Turkey; National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, Turkey.
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Xu R, Thibos LN, Lopez-Gil N, Kollbaum P, Bradley A. Psychophysical study of the optical origin of starbursts. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:B97-B102. [PMID: 31044967 DOI: 10.1364/josaa.36.000b97] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
Starbursts seen around small bright lights at night have been attributed to optical scatter, diffraction, or aberrations. We manipulated pupil aperture and aberrations to investigate the entopic appearance of perceived starbursts. The impact of circular, annular, and wedge-shaped pupil apertures, and spherical aberration sign and magnitude were used to identify pupil sub-apertures responsible for each radial perceived starburst line. Local intensity distributions within the starbursts mapped onto unique sub-regions of the pupil of both phakic and pseudophakic eyes, consistent with the hypothesis that ocular aberrations are the cause of starbursts. In paraxially focused eyes, the size of starbursts is predicted by the amount of spherical aberration, and starburst orientation is either the same or 180 deg rotated from the pupil region that creates each starburst line. No starbursts are seen when the pupil diameter is smaller than 3 mm. Replacing the eye's natural lens with a radially symmetric and optically homogeneous intraocular lens reduced the observed number of starbursts by 50%. Geometrical optics modeling including the measured aberrations of an individual eye can reveal point spread function structure that captures some of the key elements of the entopic perceptions.
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Silvestre D, Arleo A, Allard R. Healthy Aging Impairs Photon Absorption Efficiency of Cones. Invest Ophthalmol Vis Sci 2019; 60:544-551. [PMID: 30716150 DOI: 10.1167/iovs.18-25598] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Vision decline with healthy aging is a major public health concern with the unceasing growth of the aged population. In order to prevent or remedy the age-related visual loss, a better understanding of the underlying causes is needed. The current psychophysical study used a novel noise paradigm to investigate the causes of age-related contrast sensitivity loss by estimating the impact of optical factors, absorption rate of photon by photoreceptors, neural noise, and calculation efficiency on contrast sensitivity. Methods The impact of these factors on contrast sensitivity was assessed by measuring contrast thresholds with and without external noise over a wide range of spatial frequencies (0.5-16 cycles per degree [cyc/deg]) and different luminance intensities for 20 young (mean = 26.5 years, SD = 3.79) and 20 older (mean = 75.9 years, SD = 4.30) adults, all having a good visual acuity (≥6/7.5). Results The age-related contrast sensitivity losses were explained by older observers absorbing considerably fewer photons (4×), having more neural noise (1.9×), and a lower processing efficiency (1.4×). The aging effect on optical factors was not significant. Conclusions The age-related contrast sensitivity loss was mostly due to less efficient cones absorbing four times fewer photons than young adults. Thus, besides the ocular factors known to be considerably affected with aging, the decline of absorption efficiency of cones is also responsible for a considerable age-related visual decline, especially under dim light.
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Affiliation(s)
- Daphné Silvestre
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Angelo Arleo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Rémy Allard
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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Meng Q, Wang B, Cui D, Liu N, Huang Y, Chen L, Ma Y. Age-related changes in local and global visual perception. J Vis 2019; 19:10. [DOI: 10.1167/19.1.10] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Qianli Meng
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Bo Wang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Ding Cui
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Ning Liu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Yan Huang
- The Brain Cognition & Brain Disease Institute for Collaboration Research of SIAT at CAS and The McGovern Institute at MIT, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, University Town of Shenzhen, XiliNanshan, Shenzhen, Guangdong, China
| | - Lin Chen
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
| | - Yuanye Ma
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, University of Chinese Academy of Sciences, Beijing, China
- Laboratory of Primates Model for Brain Disease, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
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Abstract
The primary visual cortex (V1) is the first cortical area that processes visual information. Normal development of V1 depends on binocular vision during the critical period, and age-related losses of vision are linked with neurobiological changes in V1. Animal studies have provided important details about the neurobiological mechanisms in V1 that support normal vision or are changed by visual diseases. There is very little information, however, about those neurobiological mechanisms in human V1. That lack of information has hampered the translation of biologically inspired treatments from preclinical models to effective clinical treatments. We have studied human V1 to characterize the expression of neurobiological mechanisms that regulate visual perception and neuroplasticity. We have identified five stages of development for human V1 that start in infancy and continue across the life span. Here, we describe these stages, compare them with visual and anatomical milestones, and discuss implications for translating treatments for visual disorders that depend on neuroplasticity of V1 function.
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Affiliation(s)
- Caitlin R Siu
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada
| | - Kathryn M Murphy
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, ON, Canada.,Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
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Xu R, Wang H, Thibos LN, Bradley A. Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2017; 34:481-492. [PMID: 28375317 DOI: 10.1364/josaa.34.000481] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1 cd/m2, and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5 cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image quality remain throughout the photopic and mesopic ranges. However, restricting pupils to <2 mm will cause significant reductions in the best focus vision at low photopic and mesopic luminances.
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10
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Affiliation(s)
- Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Alabama 35294;
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11
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Katada Y, Negishi K, Watanabe K, Shigeno Y, Saiki M, Torii H, Kaido M, Tsubota K. Functional Visual Acuity of Early Presbyopia. PLoS One 2016; 11:e0151094. [PMID: 26959362 PMCID: PMC4784926 DOI: 10.1371/journal.pone.0151094] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/22/2016] [Indexed: 11/18/2022] Open
Abstract
Purpose To evaluate visual function in patients with early presbyopia using the functional visual acuity (FVA) test. Methods This study included 27 eyes of 27 healthy older volunteers (mean age, 44.1 ± 2.6 years) and 14 eyes of 14 healthy young volunteers (mean age, 28.4±4.8 years). The distance-corrected visual acuity (DCVA), distance-corrected near VA (DCNVA), subjective amplitude of accommodation (AA), and distance and near pupillary diameters were measured. The distance FVA and distance-corrected near FVA (DCNFVA) were measured using the FVA Measurement System. The standard Schirmer test and standard tear break-up time measurement also were performed. Results The logarithm of the minimum angle of resolution (logMAR) DCVA was better than 0 in all subjects. The percentages of subjects with logMAR DCNVA below 0 was significantly lower in the presbyopia group than in the young group. The DCNFVA in the presbyopia group was significantly (P < 0.001) poorer than the DCNVA in that group. Significant linear negative correlations were seen between the DCNVA and AA (r = -0.507, P < 0.001) and the DCNFVA and AA (r = -0.681, P < 0.001) in the older subjects. Stepwise regression analysis showed that only the AA was a significant factor predictive of the DCNFVA in the presbyopia group. Tear function parameters were not adopted in the regression model. Conclusions Measurement of the DCNFVA can detect decreased AA in early presbyopia better than measurement of the conventional near VA. The DCNFVA is a good index for early presbyopia.
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Affiliation(s)
- Yusaku Katada
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Kazuno Negishi
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
- * E-mail:
| | - Kazuhiro Watanabe
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Yuta Shigeno
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Megumi Saiki
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Hidemasa Torii
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Minako Kaido
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Japan
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Calvo-Maroto AM, Perez-Cambrodí RJ, Albarán-Diego C, Pons A, Cerviño A. Optical quality of the diabetic eye: a review. Eye (Lond) 2014; 28:1271-80. [PMID: 25125072 DOI: 10.1038/eye.2014.176] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/26/2014] [Indexed: 12/15/2022] Open
Abstract
Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each of ocular component have been described in detail during the past decades. Due to these abnormalities, the diabetic patient undergoes a degradation of the retinal image by an increase of higher ocular aberrations and ocular scattering coming from mainly tear film, cornea, and crystalline lens. This review aims to provide an overview of current knowledge about the effects of diabetes mellitus in these optical phenomena and its consequence on the visual quality of the diabetic patient.
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Affiliation(s)
- A M Calvo-Maroto
- Optometry Research Group, Department of Optics, University of Valencia, Valencia, Spain
| | - R J Perez-Cambrodí
- Department of Ophthalmology, Oftalmar, Medimar International Hospital, Alicante, Spain
| | - C Albarán-Diego
- Optometry Research Group, Department of Optics, University of Valencia, Valencia, Spain
| | - A Pons
- Optometry Research Group, Department of Optics, University of Valencia, Valencia, Spain
| | - A Cerviño
- Optometry Research Group, Department of Optics, University of Valencia, Valencia, Spain
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Abstract
The present study investigated the effects of presbyopia on the reading ability of middle-aged adults in a Japanese reading context, using the rapid serial visual presentation paradigm. Japanese words, each consisting of three characters, were sequentially presented at the same location on a display screen. Participants were instructed to read the words aloud as accurately as possible, irrespective of their order within the sequence. Experiment 1 showed that the reading performance for the presbyopes was far worse for the near-viewing (35 cm) than for the far-viewing (70 cm) conditions when the words were presented at 0.4° in character size. Experiment 2 investigated in detail the effect of luminance contrast on reading at a viewing distance of 35 cm. The minimums of the exposure durations within which the participants could read the words above 89.9 % correct (minimum exposure duration) were 498 ms/word for the presbyopes and 134 ms/word for the nonpresbyopes, both of which values were obtained at 100 % contrast. The critical contrast-that is, the contrast that doubled the minimum exposure duration that had been obtained at 100 % contrast-was considerably higher for the presbyopes (39.2 %) than for the nonpresbyopes (16.4 %). However, the reading performance for the presbyopes was improved more than threefold when the contrast was increased to 100 % in both experiments. Thus, our results provide psychophysical evidence for the dependency of presbyopes' reading on viewing distance and luminance contrast.
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Barbur JL, Konstantakopoulou E. Changes in color vision with decreasing light level: separating the effects of normal aging from disease. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2012; 29:A27-A35. [PMID: 22330389 DOI: 10.1364/josaa.29.000a27] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The purpose of this study was to obtain additional information about the health of the retina (HR) by measuring the rate of loss of chromatic sensitivity with decreasing light level. The HR(index) is introduced to separate the effects of normal aging from early stage disease. For normal subjects the HR(index is largely independent of age (r(2)~0.1), but ~11% of clinically normal, asymptomatic, older subjects exhibit values below the 2σ limit. The HR(index provides a single number that captures how light level affects chromatic sensitivity irrespective of age and can be used to screen for preclinical signs of retinal disease.
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Affiliation(s)
- John L Barbur
- Applied Vision Research Centre, The Henry Wellcome Laboratories for Vision Sciences, The City University London, London EC1V 0HR, UK.
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Abstract
Given the increasing size of the older adult population in many countries, there is a pressing need to identify the nature of aging-related vision impairments, their underlying mechanisms, and how they impact older adults' performance of everyday visual tasks. The results of this research can then be used to develop and evaluate interventions to slow or reverse aging-related declines in vision, thereby improving quality of life. Here we summarize salient developments in research on aging and vision over the past 25 years, focusing on spatial contrast sensitivity, vision under low luminance, temporal sensitivity and motion perception, and visual processing speed.
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Affiliation(s)
- Cynthia Owsley
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294-0009, USA.
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Comparison of contrast sensitivity, depth of field and ocular wavefront aberrations in eyes with an IOL with zero versus positive spherical aberration. Graefes Arch Clin Exp Ophthalmol 2009; 247:965-73. [PMID: 19277694 DOI: 10.1007/s00417-009-1038-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 01/07/2009] [Accepted: 01/12/2009] [Indexed: 10/21/2022] Open
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Yang YR, Wanek J, Shahidi M. Representing the retinal line spread shape with mathematical functions. J Zhejiang Univ Sci B 2008; 9:996-1002. [PMID: 19067469 DOI: 10.1631/jzus.b0820184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To report a mathematical function that characterizes the double-pass line spread function (LSF) of the human eye. Determining analytical functions that represent the double-pass LSF is important because it allows modeling the optical performance of the eye. METHODS Optical section retinal images, generated in normal human eyes using a modified slit-lamp biomicroscope, were analyzed to derive the double-pass LSF by plotting the intensity distribution of laser light reflected/ scattered from the vitreoretinal interface. Three mathematical functions (Lorentzian, Gaussian, exponential) were fitted to the double-pass LSF and the root mean square error (RMSE) was calculated to provide a measure of the goodness of fit. RESULTS The Lorentzian function provided the best representation of the double-pass LSF of normal human eyes. The full width at half maximum (FWHM) of the Lorentzian fitted curve was positively correlated with age, indicating that the double-pass LSF broadens with age. Furthermore, the goodness of fit of the Lorentzian function was significantly better in younger subjects as compared with older subjects, suggesting that the fitted function to the double-pass LSF may vary according to age. CONCLUSION The results demonstrate an age-related change in the double-pass LSF width and the goodness of fit of the Lorentzian function.
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Affiliation(s)
- Yi-Rong Yang
- Department of Bioengineering, University of Illinois at Chicago, IL 60607, USA.
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