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Davies LN, Biswas S, Bullimore M, Cruickshank F, Estevez JJ, Khanal S, Kollbaum P, Marcotte-Collard R, Montani G, Plainis S, Richdale K, Simard P, Wolffsohn JS. BCLA CLEAR presbyopia: Mechanism and optics. Cont Lens Anterior Eye 2024; 47:102185. [PMID: 38796331 DOI: 10.1016/j.clae.2024.102185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
With over a billion adults worldwide currently affected, presbyopia remains a ubiquitous, global problem. Despite over a century of study, the precise mechanism of ocular accommodation and presbyopia progression remains a topic of debate. Accordingly, this narrative review outlines the lenticular and extralenticular components of accommodation together with the impact of age on the accommodative apparatus, neural control of accommodation, models of accommodation, the impact of presbyopia on retinal image quality, and both historic and contemporary theories of presbyopia.
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Affiliation(s)
- Leon N Davies
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK.
| | - Sayantan Biswas
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK
| | | | - Fiona Cruickshank
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK
| | - Jose J Estevez
- Caring Futures Institute, College of Nursing and Health Sciences, Optometry and Vision Science, Flinders University, Adelaide, Australia; Flinders Centre for Ophthalmology, Eye and Vision Research, Department of Ophthalmology, Flinders University, Adelaide, Australia
| | - Safal Khanal
- Department of Optometry and Vision Science, The University of Alabama at Birmingham, USA
| | | | | | | | - Sotiris Plainis
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK; Laboratory of Optics and Vision, School of Medicine, University of Crete, Greece
| | | | - Patrick Simard
- School of Optometry, Universite de Montreal, Montreal, Quebec, Canada
| | - James S Wolffsohn
- School of Optometry, College of Health and Life Sciences, Aston University, Birmingham, UK
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2
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Rohman L, Ruggeri M, Ho A, Parel JM, Manns F. Lens Thickness Microfluctuations in Young and Prepresbyopic Adults During Steady-State Accommodation. Invest Ophthalmol Vis Sci 2023; 64:12. [PMID: 36753168 PMCID: PMC9919620 DOI: 10.1167/iovs.64.2.12] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 01/22/2023] [Indexed: 02/09/2023] Open
Abstract
Purpose To determine whether lens mechanical dynamics change with age and with accommodative demands. Methods Lens thickness microfluctuations were measured using a high-speed custom-built spectral domain optical coherence tomography system in five young adults (20 to 25 years old) at 0 diopters (D), 2 D, 4 D, and maximum accommodative demand and in five prepresbyopes (38 to 45 years old) under relaxed and maximal accommodation. For each state, the measurements were repeated four times during the same session. Images of the central 2-mm zone of the lens comprising 170 A-lines/frame were acquired for 10 seconds, and axial lens thickness change was measured. Lens thickness microfluctuations (µm²/Hz) were assessed by integrating the power spectrum of lens thickness microfluctuations between 0 and 4 Hz. Results The amplitude of lens microfluctuations was higher in the accommodated states than in the relaxed state in both age groups. Lens microfluctuations were higher in young adult participants than in prepresbyopes, with a significant difference in relaxed and maximally accommodated states (P = 0.04 and P = 0.04). In the young participants, the amplitude of microfluctuations reached a plateau at maximum accommodation. Conclusions Lens mechanical dynamics are both age and accommodation dependent. The decrease in lens thickness microfluctuations with age is consistent with an age-related increase in lens stiffness or decrease of the ciliary muscle displacement. The lens does not contribute to the high-frequency component of ocular dioptric microfluctuations.
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Affiliation(s)
- Leana Rohman
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
| | - Marco Ruggeri
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
| | - Arthur Ho
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
- Brien Holden Vision Institute, Sydney, New South Wales, Australia
- School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
| | - Jean-Marie Parel
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
- Brien Holden Vision Institute, Sydney, New South Wales, Australia
| | - Fabrice Manns
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States
- Department of Biomedical Engineering, University of Miami College of Engineering, Coral Gables, Florida, United States
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3
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Variability of Accommodative Microfluctuations in Myopic and Emmetropic Juveniles during Sustained near Work. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19127066. [PMID: 35742313 PMCID: PMC9222619 DOI: 10.3390/ijerph19127066] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/31/2022] [Accepted: 06/06/2022] [Indexed: 11/26/2022]
Abstract
Near work has been considered to be a potential risk factor for the onset of myopia, but with inadequate evidence. Chinese adolescents use digital devices for near work, such as study and entertainment purposes, especially during the COVID-19 pandemic. In this study, we investigated the influence of prolonged periods of near work on accommodative response, accommodative microfluctuations (AMFs), and pupil diameter between juvenile subjects of myopia and emmetropia. Sixty juveniles (30 myopes and 30 emmetropes) were recruited for the study. Participants were instructed to play a video game on a tablet PC at a distance of 33.3 cm for 40 min. Accommodative response and pupil diameter were measured with an open-field infrared refractometer in High-speed mode. Parameters of the subjects were measured once every 10 min, and analyzed by one-way repeated measure ANOVA for variation tendency. There were no significant differences between emmetropia and myopia groups with respect to age and sex (p > 0.05). The low-frequency component (LFC) of myopia gradually increased with time, reached a peak at 30 min, and then declined (p = 0.043). The high-frequency component (HFC) of myopia also reached a peak at 30 min (p = 0.036). Nevertheless, there was no significant difference in the LFC (p = 0.171) or HFC (p = 0.278) of the emmetropia group at each time point. There was no significant difference in the mean and standard deviation of the accommodative response and pupil diameter both in emmetropic and myopic juveniles. Compared with juvenile emmetropes, myopes exhibit an unstable tendency in their accommodation system for prolonged near work at a certain time point. Accommodative microfluctuations may be a sensitive, objective indicator of fatigue under sustained near work in juvenile myopes.
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Hynes NJ, Cufflin MP, Hampson KM, Mallen EA. The effect of image resolution of display types on accommodative microfluctuations. Ophthalmic Physiol Opt 2022; 42:514-525. [PMID: 35107178 PMCID: PMC9302673 DOI: 10.1111/opo.12949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 12/06/2021] [Accepted: 12/06/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE To determine whether accommodative microfluctuations (AMFs) are affected by the image resolution of the display type being observed. The effect of refractive error is also examined. METHODS Twenty participants, (10 myopes and 10 emmetropes) observed a target on four different displays: paper, smartphone, e-reader and visual display unit screen (VDU), whilst their accommodative responses were measured using a continuous recording infrared autorefractor. The accommodative response and AMF measures comprising low frequency components (LFC), high frequency components (HFC) and the root mean square (RMS) of the AMFs were analysed. RESULTS A significant increase in LFC power was observed for the paper stimulus when compared to the VDU and smartphone conditions. Myopes demonstrated a significantly higher LFC and mean accommodative response compared to emmetropes across the four displays. A significant difference in the mean AR between the displays with the lowest and highest resolution was found. A higher mean AR was found with higher resolution of the image. The HFC and RMS accommodation were not affected by display type. CONCLUSION The mean accommodative response and the mean LFC power appear to respond differently depending on the type of display in use. Higher resolution devices showed a reduced lag of accommodation to the accommodative demand; however, this may cause a lead of accommodation in myopes for higher resolution display types.
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Affiliation(s)
- Niall J Hynes
- Department of Optometry and Vision Sciences, School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Matthew P Cufflin
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - Karen M Hampson
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Edward Ah Mallen
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
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5
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Leroux CE, Leahy C, Fontvieille C, Bardin F. The random walk of accommodation fluctuations. BIOMEDICAL OPTICS EXPRESS 2021; 12:6897-6908. [PMID: 34858687 PMCID: PMC8606129 DOI: 10.1364/boe.433926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/19/2021] [Accepted: 08/03/2021] [Indexed: 06/13/2023]
Abstract
The focusing distance of the eye fluctuates during accommodation. However, the visual role of these accommodation fluctuations is not yet fully understood. The fluctuation complexity is one of the obstacles to this long standing challenge in visual science. In this work we seek to develop a statistical approach that i) accurately describes experimental measurements and ii) directly generates randomized and realistic simulations of accommodation fluctuations for use in future experiments. To do so we use the random walk approach, which is usually appropriate to describe the dynamics of systems that combine both randomness and memory.
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Affiliation(s)
| | - Conor Leahy
- Carl Zeiss Meditec, Inc., 5300 Central Parkway, Dublin, CA 94568, USA
| | | | - Fabrice Bardin
- Laboratoire MIPA, Université de Nîmes, Sites des Carmes, Nîmes, 30000, France
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6
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Zhang L, Guo D, Xie C, Wen Y, Zhang X, Jin L, Tong J, Shen Y. The effects of colour and temporal frequency of flickering light on variability of the accommodation response in emmetropes and myopes. BMC Ophthalmol 2021; 21:88. [PMID: 33596849 PMCID: PMC7890996 DOI: 10.1186/s12886-021-01856-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/25/2021] [Indexed: 02/04/2023] Open
Abstract
Background Myopia is hypothesized to be influenced by environmental light conditions. For example, it has been shown that colour and temporal frequency of flickering light affect emmetropisation in animals. Considering the omnipresence of flickering light in our daily life, we decided to analyze the effect of colour flickers on variability of the accommodation response (VAR) in emmetropes and myopes. Methods We measured the dynamic accommodative responses of 19 emmetropic and 22 myopic adults using a Grand Seiko WAM-5500 open-field autorefractor. The subjects focused for more than 20 s on a black Snellen E target against three different backgrounds made up of three colour flicker combinations (red/green, red/blue and blue/green) and under five frequency conditions (0.20 Hz, 0.50 Hz, 1.00 Hz, 1.67 Hz, and 5.00 Hz). Results Flicker frequency and colour both had a significant effect on VAR. Lower frequencies were associated with larger variability. Colour had an effect only at low frequencies, and red/blue colour flicker resulted in the largest variability. The variability in myopes were larger than those in emmetropes. Conclusions These findings support the hypothesis that further studies on the colour and temporal frequency of flickering light can lead to a better understanding of the development and progression of myopia.
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Affiliation(s)
- Liyue Zhang
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Dongyu Guo
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Chen Xie
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Yingying Wen
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Xuhong Zhang
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Le Jin
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Jianping Tong
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Ye Shen
- Department of Ophthalmology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
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7
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Disrupted potassium ion homeostasis in ciliary muscle in negative lens-induced myopia in Guinea pigs. Arch Biochem Biophys 2020; 688:108403. [PMID: 32418893 DOI: 10.1016/j.abb.2020.108403] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/09/2020] [Accepted: 05/01/2020] [Indexed: 11/21/2022]
Abstract
Myopia is a main cause of preventable or treatable visual impairment, it has become a major public health issue due to its increasingly high prevalence worldwide. Currently, it is confirmed that the development of myopia is associated with the disorders of accommodation. As a dominant factor for accommodation, ciliary muscle contraction/relaxation can regulate the physiological state of the lens and play a crucial role in the development of myopia. To investigate the relationship between myopia and ciliary muscle, the guinea pigs were randomly divided into a normal control (NC) group and a negative lens-induced myopia (LIM) group, and the animals in each group were further randomly assigned into 2-week (n = 18) and 4-week (n = 21) subgroups in accordance with the duration of myopic induction of 2 and 4 weeks, respectively. In the present study, right eyes of the animals in LIM group were covered with -6.0 D lenses to induce myopia. Next, we performed the haematoxylin and eosin (H&E) staining to observe the pathological change of ciliary muscle, determined the contents of adenosine triphosphate (ATP) and lactate acid (LA), and measured the Na+/K+-ATPase expression and activity in ciliary muscles in both NC and LIM groups. Moreover, we also analyzed the potassium ion (K+) flux in ciliary muscles from 4-week NC and LIM guinea pigs. As a result, we found that the arrangements of ciliary muscles in LIM guinea pigs were broken, dissolved or disorganized; the content of ATP decreased, whereas the content of LA increased in ciliary muscles from LIM guinea pigs. Monitoring of K+ flux in ciliary muscles from LIM guinea pigs demonstrated myopia-triggered K+ influx. Moreover, we also noted a decreased expression of Na+/K+-ATPase (Atp1a1) at both mRNA and protein levels and reduced activity in ciliary muscles from LIM guinea pigs. Overall, our results will facilitate the understanding of the mechanism associated with inhibitory Na+/K+-ATPase in lens-induced myopia and which consequently lead to the disorder of microenvironment within ciliary muscles from LIM guinea pigs, paving the way for a promising adjuvant approach in treating myopia in clinical practice.
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8
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Objective User Visual Experience Evaluation When Working with Virtual Pixel-Based 3D System and Real Voxel-Based 3D System. PHOTONICS 2019. [DOI: 10.3390/photonics6040106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Volumetric display shows promising implications for healthcare related applications as an innovative technology that creates real three-dimensional (3D) image by illuminating points in three-dimensional space to generate volumetric images without image separation. We used eccentric photorefractometry to objectively study ocular performance in a practical environment by evaluating near work-induced refraction shift, accommodative microfluctuations, and pupil size for 38 young adults after viewing anaglyph, and volumetric 3D content for prolonged time. The results of our study demonstrate that participants who performed relative depth estimation task on volumetric 3D content were less likely to experience task-induced myopic refraction shift. For both 3D content types, we observed pupil constriction, that is possibly related to visual fatigue. For anaglyph 3D pupil constriction, onset was observed significantly sooner, compared to volumetric 3D. Overall, sustained work with 3D content, and small disparities or the fully eliminated possibility of accommodation-vergence conflict, not only minimizes near work-induced myopic shift, but also provide beneficial accommodation relaxation that was demonstrated in this study as hypermetropic shift for nearly half of participants.
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Sanz Diez P, Ohlendorf A, Schaeffel F, Wahl S. Effect of spatial filtering on accommodation. Vision Res 2019; 164:62-68. [PMID: 31356834 DOI: 10.1016/j.visres.2019.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 07/12/2019] [Accepted: 07/22/2019] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to develop and test a new method that uses natural images to investigate the influence of their spatial frequency content on the accommodation response (AR). Furthermore, the minimum spatial frequency content was determined that was necessary to induce an AR. Blur of the images was manipulated digitally in the Fourier domain by filtering with a Sinc function. Fourteen young subjects participated in the experiment. A 2-step procedure was used: (1) verifying that a high amount of Sinc-blur does not evoke accommodation, (2) increasing the width of the Sinc-blur filter in logarithmic steps until an AR was evoked. AR was continuously monitored using eccentric infrared photorefraction at 60 Hz sampling rate under monocular viewing conditions. Under condition (1), Sinc-blur of λ = 1 cpd did not evoke accommodation, while under condition (2) an average (mean ± standard deviation) Sinc-blur of λ = 5.57 ± 4.67 cpd (median: 4 cpd, interquartile range: 2-7 cpd) evoked accommodation. Dividing the subjects into myopes and emmetropes revealed that the myopic group required higher amounts of λ (higher spatial frequencies) to stimulate their accommodation (mean λ = 9.33 ± 4.99 cpd, for myopes; and mean λ = 2.75 ± 0.97 cpd, for emmetropes). Our results support the notion that the AR is most effectively stimulated at mid-spatial frequencies and that myopes may require higher spatial frequencies to elicit a comparable AR.
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Affiliation(s)
- Pablo Sanz Diez
- Carl Zeiss Vision International GmbH, Turnstrasse 27, 73430 Aalen, Germany; Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany.
| | - Arne Ohlendorf
- Carl Zeiss Vision International GmbH, Turnstrasse 27, 73430 Aalen, Germany; Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
| | - Frank Schaeffel
- Section of Neurobiology of the Eye, Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
| | - Siegfried Wahl
- Carl Zeiss Vision International GmbH, Turnstrasse 27, 73430 Aalen, Germany; Institute for Ophthalmic Research, Eberhard Karls University Tuebingen, Elfriede-Aulhorn-Straße 7, 72076 Tuebingen, Germany
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10
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Xu J, Lu X, Zheng Z, Bao J, Singh N, Drobe B, Chen H. The Effects of Spatial Frequency on the Accommodative Responses of Myopic and Emmetropic Chinese Children. Transl Vis Sci Technol 2019; 8:65. [PMID: 31293819 PMCID: PMC6602141 DOI: 10.1167/tvst.8.3.65] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 03/29/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose The spatial frequency (SF) characteristics of accommodation in children are not well understood. In this study, we measured accommodative responses to grating targets to investigate the SF dependence of accommodation in children. Methods The effects of SF and contrast on the accommodative system were evaluated in two groups of children, including 22 with emmetropia and 20 with myopia. The contrast detection thresholds at five SFs were measured using a near-contrast sensitivity function test. The accommodative responses to grating targets with low (1.5 cycles per degree [cpd]), medium (6 cpd), and high (18 cpd) SFs were measured with a Grand Seiko WAM-5500 in dynamic mode for 30 seconds under standard and detection threshold contrast conditions. The accommodative lag and accommodative microfluctuations (AMFs) were compared between the two groups. Results Under standard contrast conditions, no significant difference was found in the accommodative lag across SFs (F = 2.03, P = 0.14) or between the two groups (F = 3.57, P = 0.07). The AMFs were lowest at 6 cpd in emmetropia group (F = 6.51, P = 0.003) and in total (F = 10.82, P < 0.001). Children in emmetropia group showed greater AMFs at high SFs under detection threshold contrast conditions than under standard contrast conditions (P < 0.05). Conclusions This study demonstrated that the instability of accommodation was SF dependent in children. The AMFs in children were smallest at the medium SF for standard contrast grating targets. Myopic children are less sensitive to the low-contrast-induced blur for high SFs than emmetropic children. Translational Relevance This study provides a possibility to stabilize accommodative response of children by transforming SF components of fixation targets.
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Affiliation(s)
- Jingjing Xu
- Wenzhou Medical University (WMU), Wenzhou, China.,WMU-Essilor International Research Centre (WEIRC), Wenzhou, China
| | - Xin Lu
- Ningbo Medical Center Lihuili Hospital, Ningbo, China
| | - Zhili Zheng
- Wenzhou Medical University (WMU), Wenzhou, China
| | - Jinhua Bao
- Wenzhou Medical University (WMU), Wenzhou, China.,WMU-Essilor International Research Centre (WEIRC), Wenzhou, China
| | - Nisha Singh
- R&D Vision Sciences AMERA, Essilor International, Singapore
| | - Björn Drobe
- WMU-Essilor International Research Centre (WEIRC), Wenzhou, China.,R&D Vision Sciences AMERA, Essilor International, Singapore
| | - Hao Chen
- Wenzhou Medical University (WMU), Wenzhou, China.,WMU-Essilor International Research Centre (WEIRC), Wenzhou, China
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11
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Abstract
Blur occurs naturally when the eye is focused at one distance and an object is presented at another distance. Computer-graphics engineers and vision scientists often wish to create display images that reproduce such depth-dependent blur, but their methods are incorrect for that purpose. They take into account the scene geometry, pupil size, and focal distances, but do not properly take into account the optical aberrations of the human eye. We developed a method that, by incorporating the viewer's optics, yields displayed images that produce retinal images close to the ones that occur in natural viewing. We concentrated on the effects of defocus, chromatic aberration, astigmatism, and spherical aberration and evaluated their effectiveness by conducting experiments in which we attempted to drive the eye's focusing response (accommodation) through the rendering of these aberrations. We found that accommodation is not driven at all by conventional rendering methods, but that it is driven surprisingly quickly and accurately by our method with defocus and chromatic aberration incorporated. We found some effect of astigmatism but none of spherical aberration. We discuss how the rendering approach can be used in vision science experiments and in the development of ophthalmic/optometric devices and augmented- and virtual-reality displays.
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Affiliation(s)
- Steven A Cholewiak
- Optometry & Vision Science, University of California, Berkeley, Berkeley, CA, USA
| | - Gordon D Love
- Computer Science & Physics, Durham University, Durham, UK
| | - Martin S Banks
- Optometry & Vision Science, University of California, Berkeley, Berkeley, CA, USA
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12
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Hynes NJ, Cufflin MP, Hampson KM, Mallen EAH. Cognitive Demand and Accommodative Microfluctuations. Vision (Basel) 2018; 2:vision2030036. [PMID: 31735899 PMCID: PMC6836075 DOI: 10.3390/vision2030036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/31/2018] [Accepted: 09/04/2018] [Indexed: 12/29/2022] Open
Abstract
Previous studies have shown cognition to have an influence on accommodation. Temporal variation in the accommodative response occurs during the fixation on a stationary target. This constantly shifting response has been called accommodative micro-fluctuations (AMFs). The aim of this study is to determine the effects of increasing task cognitive demand on the ocular accommodation response. AMFs for 12 myopes and 12 emmetropes were measured under three conditions of varying cognitive demand and comprising reading of numbers (Num), simple arithmetic (SA), and complex arithmetic (CA). Fast Fourier transforms were used to analyze the different frequency band components of the AMFs. Other aspects of AMFs including root mean square accommodation values and chaos analysis was applied. A repeated measures ANOVA revealed a significant main effect of cognition in the mean power of the high frequency component (HFC) (F2,44 = 10.03, p < 0.005). Pairwise analyses revealed that these differences exist between SA and CA tasks (p < 0.005) and the Num and CA (p < 0.005) tasks with the HFC power being the highest for the CA condition. It appears that the difficulty of a task does affect active accommodation but to a lesser extent than other factors affecting accommodation.
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Affiliation(s)
- Niall J. Hynes
- School of Optometry & Vision Science, University of Bradford, Bradford BD7 1DP, UK
- Correspondence:
| | - Matthew P. Cufflin
- School of Optometry & Vision Science, University of Bradford, Bradford BD7 1DP, UK
| | - Karen M. Hampson
- Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK
| | - Edward A. H. Mallen
- School of Optometry & Vision Science, University of Bradford, Bradford BD7 1DP, UK
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13
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Marín-Franch I, Del Águila-Carrasco AJ, Bernal-Molina P, Esteve-Taboada JJ, López-Gil N, Montés-Micó R, Kruger PB. There is more to accommodation of the eye than simply minimizing retinal blur. BIOMEDICAL OPTICS EXPRESS 2017; 8:4717-4728. [PMID: 29082097 PMCID: PMC5654812 DOI: 10.1364/boe.8.004717] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/02/2017] [Indexed: 06/07/2023]
Abstract
Eyes of children and young adults change their optical power to focus nearby objects at the retina. But does accommodation function by trial and error to minimize blur and maximize contrast as is generally accepted? Three experiments in monocular and monochromatic vision were performed under two conditions while aberrations were being corrected. In the first condition, feedback was available to the eye from both optical vergence and optical blur. In the second, feedback was only available from target blur. Accommodation was less precise for the second condition, suggesting that it is more than a trial-and-error function. Optical vergence itself seems to be an important cue for accommodation.
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Affiliation(s)
- I. Marín-Franch
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
- Department of Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama, USA
| | - A. J. Del Águila-Carrasco
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
| | - P. Bernal-Molina
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
| | - J. J. Esteve-Taboada
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
| | - N. López-Gil
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
- Science Vision Group (CiViUM), Instituto Universitario de Investigación en Envejecimiento, University of Murcia, Spain
| | - R. Montés-Micó
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
- Interuniversity Laboratory for Research in Vision and Optometry, Mixed Group UVEG-UMU, Valencia-Murcia, Spain
| | - P. B. Kruger
- State College of Optometry, State University of New York, New York, USA
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14
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Effect of Illumination on Ocular Status Modifications Induced by Short-Term 3D TV Viewing. Neural Plast 2017; 2017:1432037. [PMID: 28348893 PMCID: PMC5350379 DOI: 10.1155/2017/1432037] [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: 10/24/2016] [Revised: 12/22/2016] [Accepted: 01/29/2017] [Indexed: 11/25/2022] Open
Abstract
Objectives. This study aimed to compare changes in ocular status after 3D TV viewing under three modes of illumination and thereby identify optimal illumination for 3D TV viewing. Methods. The following measures of ocular status were assessed: the accommodative response, accommodative microfluctuation, accommodative facility, relative accommodation, gradient accommodative convergence/accommodation (AC/A) ratio, phoria, and fusional vergence. The observers watched 3D television for 90 minutes through 3D shutter glasses under three illumination modes: A, complete darkness; B, back illumination (50 lx); and C, front illumination (130 lx). The ocular status of the observers was assessed both before and after the viewing. Results. After 3D TV viewing, the accommodative response and accommodative microfluctuation were significantly changed under illumination Modes A and B. The near positive fusional vergence decreased significantly after the 90-minute 3D viewing session under each illumination mode, and this effect was not significantly different among the three modes. Conclusions. Short-term 3D viewing modified the ocular status of adults. The least amount of such change occurred with front illumination, suggesting that this type of illumination is an appropriate mode for 3D shutter TV viewing.
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15
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The effects of spatial frequency on the accommodation responses of myopes and emmetropes under various detection demands. Vision Res 2015. [DOI: 10.1016/j.visres.2015.05.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Charman WN, Heron G. Microfluctuations in accommodation: an update on their characteristics and possible role. Ophthalmic Physiol Opt 2015; 35:476-99. [DOI: 10.1111/opo.12234] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 07/23/2015] [Indexed: 11/30/2022]
Affiliation(s)
- W Neil Charman
- Faculty of Life Sciences; University of Manchester; Manchester UK
| | - Gordon Heron
- Vision Sciences; Glasgow Caledonian University; Glasgow UK
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17
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O'Hare L, Hibbard PB. Spatial frequency and visual discomfort. Vision Res 2011; 51:1767-77. [PMID: 21684303 DOI: 10.1016/j.visres.2011.06.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 05/27/2011] [Accepted: 06/03/2011] [Indexed: 11/16/2022]
Affiliation(s)
- Louise O'Hare
- School of Psychology, University of St. Andrews, St. Mary's Quad, South Street, St. Andrews, Fife KY16 9JP, United Kingdom.
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18
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Strang NC, Day M, Gray LS, Seidel D. Accommodation steps, target spatial frequency and refractive error. Ophthalmic Physiol Opt 2011; 31:444-55. [PMID: 21651598 DOI: 10.1111/j.1475-1313.2011.00855.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Errors in the accommodation response of myopes have been reported in many studies although questions remain about the exact differences in accommodation steps when compared with emmetropic individuals. METHODS The characteristics of the accommodation step response to large (4/1D) and small (3/2D) steps in targets with low (0.5 cpd), mid (4 cpd) and high (16 cpd) spatial frequency (SF) information was measured in myopes (MYOs) and emmetropes (EMMs). RESULTS In terms of step size, the larger steps showed a greater response in the 4 cpd condition than the 0.5 and 16 cpd conditions and an improved percentage correct response in the 4 cpd compared to the 16 cpd steps. In small step conditions target SF had less effect upon the magnitude of the response. In terms of refractive group differences, MYOs had a lower proportion of correct accommodation responses compared to EMMs during the small steps only, however, when correct steps were performed there were no differences in the characteristics of both large and small step responses between MYOs and EMMs. CONCLUSIONS These findings suggest that MYOs have some difficulty interpreting small changes in defocus to initiate or possibly fine tune a small accommodation response, however, when a correct accommodation step response is made, the MYOs accommodation plant responds in a similar manner to EMMs.
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Affiliation(s)
- Niall C Strang
- Department of Vision Sciences, Glasgow Caledonian University, Glasgow, UK
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19
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Effect of near adds on the variability of accommodative response in myopic children. Ophthalmic Physiol Opt 2011; 31:145-54. [DOI: 10.1111/j.1475-1313.2010.00818.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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