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Bartuzel MM, Consejo A, Stremplewski P, Sylwestrzak M, Szkulmowski M, Gorczynska I. In vivo identification of the retinal layer containing photopigments in OCT images through correlation with two-photon psychophysics. Sci Rep 2024; 14:15459. [PMID: 38965299 PMCID: PMC11224378 DOI: 10.1038/s41598-024-65234-7] [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: 02/14/2024] [Accepted: 06/18/2024] [Indexed: 07/06/2024] Open
Abstract
Two-photon vision enables near-infrared light perception in humans. We investigate the possibility to utilize this phenomenon as an indicator of the location of the outer segments of photoreceptor cells in the OCT images. Since two-photon vision is independent on OCT imaging, it could provide external to OCT reference relative to which positions of retinal layers visible in OCT imaging could be measured. We show coincidence between OCT imaging of outer retinal layers and two-photon light perception. The experiment utilizes an intrinsic nonlinear process in the retina, two-photon absorption of light by visual photopigments, which triggers perception of near-infrared light. By shifting the focus of the imaging/stimulus beam, we link the peak efficiency of two-photon vision with the visibility of outer segments of photoreceptor cells, which can be seen as in vivo identification of a retinal layer containing visual photopigments in OCT images. Determination of the in-focus retinal layer is achieved by analysis of en face OCT image contrast. We discuss experimental methods and experimental factors that may influence two-photon light perception and the accuracy of the results. The limits of resolution are discussed in analysis of the one-photon and two-photon point spread functions.
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Affiliation(s)
- Maciej M Bartuzel
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Toruń, Poland.
| | - Alejandra Consejo
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Patrycjusz Stremplewski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Toruń, Poland
| | - Marcin Sylwestrzak
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Toruń, Poland
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Toruń, Poland
| | - Iwona Gorczynska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Toruń, Poland
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2
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Pourreza Ghoushchi V, Mompeán J, Prieto PM, Artal P. Contrast sensitivity is resilient to induced fast periodic defocus oscillations. BIOMEDICAL OPTICS EXPRESS 2024; 15:3848-3858. [PMID: 38867768 PMCID: PMC11166443 DOI: 10.1364/boe.521340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 06/14/2024]
Abstract
This study investigates the potential effects of periodic defocus oscillations on contrast sensitivity. Sinusoidal fluctuations at 5, 15, and 25 Hz, with defocus peak-to-valley values ranging from 0.15 to 3 D, were induced by means of a focus-tunable lens after calibrating its dynamic behavior. Monocular contrast sensitivity was measured on five young emmetropic subjects. The experimental data shows that contrast sensitivity loss due to defocus fluctuations is low for a wide range of frequencies and amplitudes. Only for the more severe case studied (25 Hz, ± 1.5 D) contrast threshold showed a clear increase in most subjects. Qualitative comparison of the empirical data with a simulation of modulation loss due to time integration of defocused retinal point spread functions, suggests a short integration time by the eye for defocus blur, around or even below a hundredth of a second.
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Affiliation(s)
- Vahid Pourreza Ghoushchi
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), E-30100 Murcia, Spain
| | - Juan Mompeán
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), E-30100 Murcia, Spain
| | - Pedro M. Prieto
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), E-30100 Murcia, Spain
| | - Pablo Artal
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), E-30100 Murcia, Spain
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3
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Ghorbani-Mojarrad N, Hussain M, Mankowska A, Mallen E, Cufflin M. Effect of myopia management contact lens design on accommodative microfluctuations and eye movements during reading. Cont Lens Anterior Eye 2024; 47:102095. [PMID: 38057197 DOI: 10.1016/j.clae.2023.102095] [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] [Received: 06/30/2023] [Revised: 09/29/2023] [Accepted: 11/25/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Soft contact lenses have been developed and licensed for reducing myopia progression. These lenses have different designs, such as extended depth of focus (EDOF) and dual focus (DF). In this prospective, double-masked, cross-over study, different lens designs were investigated to see whether these had impact on accommodative microfluctuations and eye movements during reading. METHODS Participants were fitted with three lenses in a randomised order; a single vision (SV) design (Omafilcon A2; Proclear), a DF design (Omafilcon A2; MiSight), and an EDOF lens design (Etafilcon A; NaturalVue),. Accommodative microfluctuations were measured at 25 cm for at least 60s in each lens, using a Shin-Nippon SRW-5000 autorefractor adapted to continuously record accommodation at 22Hz. Eye movement data was collected with the Thomson Clinical Eye Tracker incorporating a Tobii Eye bar. Eye movements include fixations per row, fixations per minute, mean regressions per row, total number of regressions, and total rightward saccades. Accommodation data was analysed using power spectrum analysis. Differences between the lenses were compared using a related sample two-way Friedman test. RESULTS Twenty-three participants (18-29 years) were recruited to take part. The average mean spherical error was -2.65D ± 1.42DS, with an average age of 23.4 ± 3.5 years. No significant difference for accommodative microfluctuations was found. Significant differences were found for fixations per row (P = 0.03), fixations per minute (P = 0.008), mean regressions per row (P = 0.002), and total number of regressions (P = 0.002), but not total rightward saccades (P = 0.10). Post-hoc analysis indicated the EDOF lens results were significantly different from the other lenses, with more regressive eye movements observed. CONCLUSIONS Regressive saccades appear to increase when wearing EDOF lens designs, which may impact visual comfort. Further studies in children, over a longer period of adaptation are necessary to assess the potential impact of this finding on daily reading activities in children.
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Affiliation(s)
- Neema Ghorbani-Mojarrad
- School of Optometry and Vision Science, University of Bradford, Bradford, UK; Wolfson Centre for Applied Health Research, Bradford Teaching Hospitals, Bradford, UK.
| | - Muskaan Hussain
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | | | - Edward Mallen
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
| | - Matthew Cufflin
- School of Optometry and Vision Science, University of Bradford, Bradford, UK
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4
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Fernandez-Alonso M, Finch AP, Love GD, Read JCA. Ocular accommodation and wavelength: The effect of longitudinal chromatic aberration on the stimulus-response curve. J Vis 2024; 24:11. [PMID: 38411958 PMCID: PMC10910436 DOI: 10.1167/jov.24.2.11] [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] [Received: 06/24/2023] [Accepted: 01/06/2024] [Indexed: 02/28/2024] Open
Abstract
The longitudinal chromatic aberration (LCA) of the eye creates a chromatic blur on the retina that is an important cue for accommodation. Although this mechanism can work optimally in broadband illuminants such as daylight, it is not clear how the system responds to the narrowband illuminants used by many modern displays. Here, we measured pupil and accommodative responses as well as visual acuity under narrowband light-emitting diode (LED) illuminants of different peak wavelengths. Observers were able to accommodate under narrowband light and compensate for the LCA of the eye, with no difference in the variability of the steady-state accommodation response between narrowband and broadband illuminants. Intriguingly, our subjects compensated more fully for LCA at nearer distances. That is, the difference in accommodation to different wavelengths became larger when the object was placed nearer the observer, causing the slope of the accommodation response curve to become shallower for shorter wavelengths and steeper for longer ones. Within the accommodative range of observers, accommodative errors were small and visual acuity normal. When comparing between illuminants, when accommodation was accurate, visual acuity was worst for blue narrowband light. This cannot be due to the sparser spacing for S-cones, as our stimuli had equal luminance and thus activated LM-cones roughly equally. It is likely because ocular LCA changes more rapidly at shorter wavelength and so the finite spectral bandwidth of LEDs corresponds to a greater dioptric range at shorter wavelengths. This effect disappears for larger accommodative errors, due to the increased depth of focus of the eye.
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Affiliation(s)
- Maydel Fernandez-Alonso
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
- Present address: Translational Sensory and Circadian Neuroscience Group, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | | | - Gordon D Love
- Department of Physics, Durham University, Durham, UK
- Department of Computer Sciences, Durham University, Durham, UK
- Present address: School of Computing, University of Leeds, Leeds, UK
| | - Jenny C A Read
- Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
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Ampolu N, Yarravarapu D, Satgunam P, Varadharajan LS, Bharadwaj SR. Impact of induced pseudomyopia and refractive fluctuations of accommodative spasm on visual acuity. Clin Exp Optom 2023; 106:876-882. [PMID: 36375142 DOI: 10.1080/08164622.2022.2140583] [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] [Received: 02/04/2022] [Accepted: 10/21/2022] [Indexed: 11/16/2022] Open
Abstract
CLINICAL RELEVANCE High-contrast visual acuity is disproportionately poor in patients with accommodative spasm subtype of near reflex (SNR-A), relative to uncorrected refractive errors of equivalent magnitude. This exaggerated loss of performance in SNR-A may be explained by the combination of pseudomyopia and its fluctuations, vis-à-vis, each factor considered separately. BACKGROUND To determine how combinations of pseudomyopic refraction and its temporal variations in SNR-A impact high-contrast visual acuity by inducing these patterns in healthy cyclopleged adults, relative to their baseline acuity. METHODS Refractive profiles of 15 patients with SNR-A were obtained from a previous study, averaged, and induced before the right eye of 14 cyclopleged adults (mean ±1 SD age: 22.7 ± 2.6 yrs) by feeding the profile into a coaxially placed, motorised, Badal optometer. LogMAR acuity was measured using the method of constant stimuli: (1) before cycloplegia, (2) after cycloplegia and post-cycloplegia with (3) combination of pseudomyopia and its temporal fluctuations, (4) only pseudomyopia, (5) only temporal fluctuations in refraction about emmetropia, (6) condition 5 with double the amplitude of induced fluctuations and (7) condition 5 with half the amplitude of induced fluctuations. RESULTS The induced refractive fluctuations ranged from -0.80 to -1.75D, around a mean pseudomyopia of -1.20D. Visual acuity deterioration was maximum for the combination of pseudomyopia and temporal fluctuations condition (0.51 ± 0.07logMAR), followed by only pseudomyopia (0.27 ± 0.05logMAR) and only refractive fluctuations conditions (0.17 ± 0.04logMAR), all relative to baseline post-cycloplegia (0.13 ± 0.04logMAR) (p < 0.001). Visual acuity loss increased with doubling of refractive fluctuations (0.20 ± 0.04logMAR), relative to native fluctuations or halving the amplitude (0.15 ± 0.03logMAR) (p < 0.01). Task precision, as adjudged from the slope of psychometric function, followed a similar pattern of loss as visual acuity. CONCLUSION Combination of induced pseudomyopia and temporal fluctuations in refraction produces an additive loss of visual acuity and task precision, relative to baseline and each factor considered separately.
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Affiliation(s)
- Navaneetha Ampolu
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, India
| | - Divyank Yarravarapu
- Center for Technology Innovation, L V Prasad Eye Institute, Hyderabad, India
| | | | | | - Shrikant R Bharadwaj
- Prof Brien Holden Eye Research Centre, L V Prasad Eye Institute, Hyderabad, India
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6
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Goswami S, Bharadwaj SR. Temporal fluctuations in defocus may reverse the acuity loss encountered with induced refractive errors. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2023; 40:2008-2018. [PMID: 38038066 DOI: 10.1364/josaa.497091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/02/2023] [Indexed: 12/02/2023]
Abstract
A recent template-matching model hypothesized that simulated visual acuity loss with uncorrected refractive errors may be recovered by adding temporal defocus fluctuations up to the magnitude of the refractive error. Acuity recovery saturates or gets attenuated beyond this magnitude. These predictions were confirmed for monocular high-contrast visual acuity of 10 young, cyclopleged adults with 0.5-2.0D of induced myopia combined with the same range of temporal defocus fluctuations at 4.0 Hz frequency. The outcomes reinforce that spatial resolution may be optimized by averaging time-varying defocus over the entire stimulus presentation epoch or around the point of least defocus within this epoch.
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7
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Turull-Mallofré A, García-Guerra CE, Mestre C, Vilaseca M, Pujol J, Aldaba M. Influence of power and the time of application of fogging lenses on accommodation. BIOMEDICAL OPTICS EXPRESS 2023; 14:5488-5498. [PMID: 37854562 PMCID: PMC10581808 DOI: 10.1364/boe.486442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 06/15/2023] [Accepted: 06/28/2023] [Indexed: 10/20/2023]
Abstract
Fogging is a non-invasive technique based on the use of positive spherical power lenses to relax accommodation during refraction that is commonly used as an alternative to cycloplegic drugs. Although the mechanism of the fogging technique has been described, some aspects of its methodology remain unclear. The main purpose of this work was to determine which lens power and time of application are more suitable for achieving a successful relaxation of accommodation by analyzing the changes in accommodation when fogging lenses of different powers were placed in front of the participants' eye for a certain timespan. The results of this analysis showed, in general, that low-power lenses and timespans of less than half a minute provided the highest relaxation of accommodation. However, high inter-subject variability was found in the two variables (power and time).
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Affiliation(s)
- Aina Turull-Mallofré
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
| | - Carlos E. García-Guerra
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
| | - Clara Mestre
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
| | - Meritxell Vilaseca
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
| | - Jaume Pujol
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
| | - Mikel Aldaba
- Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla Sant Nebridi 10, Terrassa, 08222, Spain
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Ntodie M, Saunders K, Little JA. Accuracy and stability of accommodation and vergence responses during sustained near tasks in uncorrected hyperopes. Sci Rep 2023; 13:14389. [PMID: 37658084 PMCID: PMC10474059 DOI: 10.1038/s41598-023-41244-9] [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: 05/29/2022] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
This study investigated the accuracy and stability of accommodative and vergence functions in children with and without hyperopia while engaged in two sustained near tasks. The sustained accommodative and vergence characteristics of participants without refractive correction (n = 92, aged 5-10 years) with and without hyperopia (defined as cycloplegic retinoscopy ≥ + 1.00D and less than + 5.00D) were measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular measures of accommodation and eye position were recorded while participants engaged in 2 tasks at 25 cm for 15 min each: (1) reading small print on an Amazon Kindle and (2) watching an animated movie on liquid crystal display screen. Comprehensive visual assessment, including measurement of presenting visual acuity, amplitude of accommodation, and stereoacuity was conducted. The magnitude of accommodative and vergence responses was not related to refractive error (P > 0.05). However, there were inter-task differences in the accuracy and stability of the accommodative responses across refractive groups (P < 0.05). The relationship between accommodation and vergence was not significant in both tasks (P > 0.05). However, increased accommodative and vergence instabilities were associated with total accommodative response (P < 0.05). Despite having greater accommodative demand, uncorrected hyperopes accommodate comparably to emmetropic controls. However, uncorrected hyperopes have increased instabilities in their accommodative and vergence responses, which may adversely impact their visual experience.
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Affiliation(s)
- Michael Ntodie
- Department of Optometry and Vision Science, School of Allied Health Sciences, College of Health and Allied Sciences, University of Cape Coast, Cape Coast, Ghana.
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK.
| | - Kathryn Saunders
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
| | - Julie-Anne Little
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, UK
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Rodriguez-Lopez V, Geisler W, Dorronsoro C. Spatiotemporal defocus sensitivity function of the human visual system. BIOMEDICAL OPTICS EXPRESS 2023; 14:3654-3670. [PMID: 37497500 PMCID: PMC10368063 DOI: 10.1364/boe.486242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 07/28/2023]
Abstract
Tunable lenses make it possible to measure visual sensitivity to rapid changes in optical power, surpassing the limits imposed by mechanical elements. Using a tunable lens system, we measured, for the first time, the spatiotemporal defocus sensitivity function (STDSF), and the limits of human defocus perception. Specifically, we measured defocus sensitivity using a QUEST adaptive psychophysical procedure for different stimuli (Gabor patches of different spatial frequencies, natural images, and edges) and we developed descriptive models of defocus perception. For Gabor patches, we found on average (across seven subjects) that the maximum sensitivity to defocus is 0.22 D at 14 cpd and 10 Hz, and that the upper limits of sensitivity are 40 cpd and 40 Hz. Our results suggest that accommodation remains fixed while performing the defocus flicker-detection task. These results have implications for new technologies whose working principles make use of fast changes to defocus.
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Affiliation(s)
- Victor Rodriguez-Lopez
- Institute of Optics, Spanish National Research Council (IO-CSIC), IO-CSIC, Serrano 121, E-28006, Madrid, Spain
| | - Wilson Geisler
- Center for Perceptual Systems, The University of Texas at Austin, 1 University Station, A8000, E-78712, Austin, Texas, USA
| | - Carlos Dorronsoro
- Institute of Optics, Spanish National Research Council (IO-CSIC), IO-CSIC, Serrano 121, E-28006, Madrid, Spain
- Center for Perceptual Systems, The University of Texas at Austin, 1 University Station, A8000, E-78712, Austin, Texas, USA
- 2EyesVision SL, Plaza de la Encina, 10, núcleo 3, planta 4ª, E-28760 Tres Cantos, Madrid, Spain
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Goswami S, Bharadwaj SR. Impact of temporal fluctuations in optical defocus on visual acuity: Empirical results and modeling outcomes. J Vis 2023; 23:14. [PMID: 36971683 PMCID: PMC10064932 DOI: 10.1167/jov.23.3.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Optical defocus in human eyes is seldom steady during naturalistic steady-state viewing. It fluctuates by 0.3 to 0.5 diopters (D) from accommodative microfluctuations and by 1.5 to 2.5 D in dysfunctions such as spasm of near reflex, both with ≤2 Hz low-pass frequency spectra. This study observed losses in monocular visual acuity of cyclopleged adults who encountered varying amplitude (0.25-2.0 D) and temporal frequency (0.25-2.0 Hz) combinations of sinusoidal defoci induced using an electrically tunable lens. Visual acuity, recorded for 300-ms flashes of Sloan optotype presentation using the method of constant stimuli, deteriorated with defocus amplitude at a rate steeper for lower than higher temporal frequencies. A template matching model of acuity, incorporating optical and neural low-pass filters, neural noise, and a cross-correlated decision operator, showed the best match with empirical data when acuity was governed by the minimum defocus available during optotype display. This criterion minimized acuity loss for higher temporal frequencies due to the increased probability of zero-defocus encounters within the presentation duration. Other decision criteria such as defocus averaging across the entire or parts of the presentation duration yielded less satisfactory results. These results imply that vision loss in humans encountering broadband time-varying defocus is dictated by the dominant low frequencies, with higher frequencies largely compensated using the least defocus decision strategy.
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Affiliation(s)
- Sabyasachi Goswami
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Prof Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Shrikant R Bharadwaj
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, Telangana, India
- Prof Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L V Prasad Eye Institute, Hyderabad, Telangana, India
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11
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Vera J, Redondo B, Galan T, Machado P, Molina R, Koulieris GA, Jiménez R. Dynamics of the accommodative response and facility with dual-focus soft contact lenses for myopia control. Cont Lens Anterior Eye 2023; 46:101526. [PMID: 34674953 DOI: 10.1016/j.clae.2021.101526] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/05/2021] [Accepted: 10/11/2021] [Indexed: 01/18/2023]
Abstract
OBJECTIVE To assess the impact of using dual-focus soft contact lenses for myopia control on the dynamics of the accommodative response and facility. METHODS 24 young adult myopes were fitted with dual-focus soft contact lenses for myopia control (MiSight®) and single-vision soft contact lenses (Proclear®). The WAM-5500 open-field autorefractor was used to measure the dynamics of the accommodative response (magnitude and variability) in binocular conditions, with accommodative data being gathered from the dominant eye, at three viewing distances (500 cm, 40 cm, and 20 cm) during 90 s. Also, the binocular accommodative facility was assessed with the WAM-5500 autorefractor. All participants performed the same experimental protocol with the dual-focus (MiSight) and single-vision (Proclear) soft contact lenses, with both experimental sessions being carried in two different days and following a counterbalanced order. RESULTS This study showed greater lags of accommodation with the MiSight than the Proclear lenses at near distances (40 cm: 1.27 ± 0.77 vs. 0.68 ± 0.37 D, corrected p-value = 0.002, Cohen-d = 0.90; and 20 cm: 1.47 ± 0.84 vs. 1.01 ± 0.52 D, corrected p-value = 0.007, Cohen-d = 0.75), whereas a higher variability of accommodation was observed with the dual-focus than the single-vision lenses at 500 cm (0.53 ± 0.11 vs. 0.23 ± 0.10 D), 40 cm (0.82 ± 0.31 vs. 0.68 ± 0.37 D), and 20 cm (1.50 ± 0.56 vs. 1.15 ± 0.39 D) (corrected p-value < 0.001 in all cases, and Cohen-ds = 0.67-2.33). Also, a worse quantitative (27.75 ± 8.79 vs. 34.29 ± 10.08 cycles per minute, p = 0.029, Cohen-d = 0.48) and qualitative (23.68 ± 7.12 vs. 28.43 ± 7.97 score, p = 0.039, Cohen-d = 0.45) performance was observed with the MiSight when compared to the Proclear lenses. CONCLUSIONS The use of dual-focus soft contact lenses for myopia control alters the dynamics of accommodative response and facility in the short-term. Although this optical design has demonstrated its effectiveness for myopia control, eye care specialists should be aware of the acute effects of these lenses on accommodation performance.
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Affiliation(s)
- Jesús Vera
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | - Beatriz Redondo
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain.
| | - Tomás Galan
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | - Pedro Machado
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain; Department of Computer Science, Durham University, UK
| | - Rubén Molina
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | | | - Raimundo Jiménez
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
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12
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Redondo B, Vera J, Molina R, Jiménez R. Less is more: optimal recording time for measuring the steady-state accommodative response. Clin Exp Optom 2023; 106:20-28. [PMID: 34839788 DOI: 10.1080/08164622.2021.2003692] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Clinical Relevance Background: Steady-state accommodation is frequently evaluated with open-field autorefractors; however there is no consensus regarding the optimal test duration. Our results allow us to standardise the procedure followed for the assessment of the steady-state accommodative response in clinical and laboratory settings and may be of great relevance in time-constrained situations. BACKGROUND The present study aims to determine the optimal recording time to assess the magnitude and variability of the accommodative response with a binocular open-field autorefractor. METHODS The steady-state accommodative response of 84 healthy undergraduate students was dynamically measured using the Grand Seiko WAM-5500 autorefractor at 500 cm, 40 cm and 20 cm for 90 s while participants maintained focus on a stationary target. We examined the reliability and level of agreement between four time intervals (the first 10-s, 30-s, 60-s and 90-s) at three accommodative demands (0.2D, 2.5D and 5D). RESULTS The magnitude of accommodation showed an excellent level of reliability (intraclass correlation coefficient [ICC]> 0.90) for the comparisons between the 90-s, 60-s and 30-s time intervals at the three viewing distances tested. However, when including the 10-s interval, there was a moderate reduction of the reliability indices and an increase of the mean difference between two time intervals (intra-class correlation [ICC] ranging from 0.89 to 0.97; and ESs ranging from 0.16 to 0.42). For the variability of accommodation, we observed an excellent reliability for the comparisons of the 90-s and 60-s measures at the three accommodative demands (ICC: 0.95-0.96), whereas for the rest of comparisons we observed from moderate to good levels of reliability. CONCLUSION Our data indicate that of 30-s and 60-s are enough to accurately assess the magnitude and variability of the accommodative response with the WAM-5500 autorefractor, respectively.
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Affiliation(s)
- Beatríz Redondo
- Claro (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | - Jesús Vera
- Claro (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | - Rubén Molina
- Claro (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
| | - Raimundo Jiménez
- Claro (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Granada, Spain
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13
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Marcos S, Artal P, Atchison DA, Hampson K, Legras R, Lundström L, Yoon G. Adaptive optics visual simulators: a review of recent optical designs and applications [Invited]. BIOMEDICAL OPTICS EXPRESS 2022; 13:6508-6532. [PMID: 36589577 PMCID: PMC9774875 DOI: 10.1364/boe.473458] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 05/02/2023]
Abstract
In their pioneering work demonstrating measurement and full correction of the eye's optical aberrations, Liang, Williams and Miller, [JOSA A14, 2884 (1997)10.1364/JOSAA.14.002884] showed improvement in visual performance using adaptive optics (AO). Since then, AO visual simulators have been developed to explore the spatial limits to human vision and as platforms to test non-invasively optical corrections for presbyopia, myopia, or corneal irregularities. These applications have allowed new psychophysics bypassing the optics of the eye, ranging from studying the impact of the interactions of monochromatic and chromatic aberrations on vision to neural adaptation. Other applications address new paradigms of lens designs and corrections of ocular errors. The current paper describes a series of AO visual simulators developed in laboratories around the world, key applications, and current trends and challenges. As the field moves into its second quarter century, new available technologies and a solid reception by the clinical community promise a vigorous and expanding use of AO simulation in years to come.
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Affiliation(s)
- Susana Marcos
- Center for Visual Sciences; The Institute of Optics and Flaum Eye Institute, University of Rochester, New York 14642, USA
| | - Pablo Artal
- Laboratorio de Optica, Universidad de Murcia, Campus Universitario de Espinardo, 30100, Spain
| | - David A. Atchison
- Centre for Vision and Eye Research, Queensland University of Technology, Brisbane Q, 4059, Australia
| | - Karen Hampson
- Department of Optometry, University of Manchester, Manchester M13 9PL, UK
| | - Richard Legras
- LuMIn, CNRS, ENS Paris-Saclay, Université Paris-Saclay, CentraleSupelec, Université Paris-Saclay Orsay, 91400, France
| | - Linda Lundström
- KTH (Royal Institute of Technology), Stockholm, 10691, Sweden
| | - Geunyoung Yoon
- College of Optometry, University of Houston, Houston, 77004, USA
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14
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Effect of Spectacle Lenses with Highly Aspherical Lenslets on Binocular Vision and Accommodation in Myopic Children with and without Intermittent Exotropia. J Ophthalmol 2022; 2022:9306848. [PMID: 36276921 PMCID: PMC9581704 DOI: 10.1155/2022/9306848] [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: 08/11/2022] [Accepted: 09/29/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose To evaluate the influence of spectacle lenses with highly aspherical lenslets (HAL) on binocular vision and accommodation in myopic children with intermittent exotropia (IXT) and compare the changes after wearing HAL in binocular vision and accommodation in myopic children with or without IXT. Method Forty myopic subjects aged 8–12 years were recruited: 20 with IXT and 20 visually normal children. Stereoacuity, phoria, accommodative facility, fusional vergence, vergence facility, near point of convergence, amplitude of accommodation, and accommodative response (AR) were measured by wearing HAL or single vision spectacle lenses (SVL) in a random order after adapting for 20 minutes. Accommodative microfluctuation (AMF) was defined as the standard deviation of AR. Changes in binocular vision and accommodation after wearing HAL were compared between the two groups. Results No significant differences were found in binocular vision after wearing HAL versus SVL in either group (all P > 0.05). A greater AMF was found after wearing HAL than after wearing SVL in both groups (0.04 D, 95% confidence interval (CI), 0.03 to 0.05 D, P < 0.001 for the IXT group; 0.05 D, 95% CI, 0.03 to 0.07 D, P < 0.001 for the visually normal group); however, the other accommodation parameters did not change significantly (all P > 0.05). There were no differences in the changes after wearing HAL in any parameter between the two groups (all P > 0.05). Conclusion HAL did not significantly change the binocular vision and accommodation for myopic children with or without IXT except for AMF in the short term.
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15
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Huang Y, Li X, Wang C, Zhou F, Yang A, Chen H, Bao J. Visual acuity, near phoria and accommodation in myopic children using spectacle lenses with aspherical lenslets: results from a randomized clinical trial. EYE AND VISION 2022; 9:33. [PMID: 36045391 PMCID: PMC9434851 DOI: 10.1186/s40662-022-00304-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 08/11/2022] [Indexed: 11/10/2022]
Abstract
Abstract
Objectives
To investigate the short- and long-term effects of myopia control spectacle lenses with highly aspherical lenslets (HAL) and slightly aspherical lenslets (SAL) on visual function and visual quality using data obtained from a randomized controlled clinical trial.
Methods
This was a prospective, randomized, controlled, and double-blinded study; 170 myopic children aged 8–13 years were randomly assigned to the HAL, SAL, or single-vision spectacle lenses (SVL) groups. Distance and near visual acuity (VA) at high (100%) and low (10%) contrast in photopic and scotopic conditions, near phoria, stereoacuity, and accommodative lag, microfluctuations (AMFs), amplitude (AA) were measured after wearing lenses for 10 min, 6 months, and 12 months.
Results
In total, 161 subjects completed all follow-up in 12 months and were included in the analysis. After 10 min of wearing, the HAL and SAL groups had lower scotopic and low-contrast VA than the SVL group (decreased 0.03–0.08 logMAR and 0.01–0.04 logMAR in different VAs in the HAL and SAL groups, respectively, all P < 0.05). The reduction in VA was recovered at 12 months as the HAL and SAL groups exhibited significant VA improvements, and the VA was not different among the three groups (all P > 0.05). The HAL and SAL groups had significantly larger AMFs than the SVL group (HAL vs. SAL vs. SVL: 0.21 ± 0.08 D vs. 0.16 ± 0.05 D vs. 0.15 ± 0.06 D at baseline, 0.19 ± 0.07 D vs. 0.17 ± 0.05 D vs. 0.13 ± 0.07 D at 12 months, all P < 0.05). There were no significant differences in accommodative lag, AA, or phoria between the groups (all P > 0.05). The HAL and SAL groups had reduced stereoacuity compared to the SVL group at baseline (70’ vs. 60’ vs. 50’, P = 0.005), but no difference was observed at 12 months (70’ vs. 70’ vs. 70’, P = 0.11).
Conclusions
HAL and SAL have no significant influence on accommodation and phoria except had larger AMF than SVL. Scotopic VA and low-contrast VA are reduced with short-term HAL and SAL use but recovered to be at same level with the SVL after 1 year of use.
Trial registration Chinese Clinical Trial Registry: ChiCTR1800017683. Registered on 9 August 2018. http://www.chictr.org.cn/showproj.aspx?proj=29789
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16
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Read JCA, Kaspiris-Rousellis C, Wood TS, Wu B, Vlaskamp BNS, Schor CM. Seeing the future: Predictive control in neural models of ocular accommodation. J Vis 2022; 22:4. [PMID: 35925580 PMCID: PMC9363677 DOI: 10.1167/jov.22.9.4] [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] [Indexed: 12/02/2022] Open
Abstract
Ocular accommodation is the process of adjusting the eye's crystalline lens so as to bring the retinal image into sharp focus. The major stimulus to accommodation is therefore retinal defocus, and in essence, the job of accommodative control is to send a signal to the ciliary muscle which will minimize the magnitude of defocus. In this article, we first provide a tutorial introduction to control theory to aid vision scientists without this background. We then present a unified model of accommodative control that explains properties of the accommodative response for a wide range of accommodative stimuli. Following previous work, we conclude that most aspects of accommodation are well explained by dual integral control, with a “fast” or “phasic” integrator enabling response to rapid changes in demand, which hands over control to a “slow” or “tonic” integrator which maintains the response to steady demand. Control is complicated by the sensorimotor latencies within the system, which delay both information about defocus and the accommodation changes made in response, and by the sluggish response of the motor plant. These can be overcome by incorporating a Smith predictor, whereby the system predicts the delayed sensory consequences of its own motor actions. For the first time, we show that critically-damped dual integral control with a Smith predictor accounts for adaptation effects as well as for the gain and phase for sinusoidal oscillations in demand. In addition, we propose a novel proportional-control signal to account for the power spectrum of accommodative microfluctuations during steady fixation, which may be important in hunting for optimal focus, and for the nonlinear resonance observed for low-amplitude, high-frequency input. Complete Matlab/Simulink code implementing the model is provided at https://doi.org/10.25405/data.ncl.14945550.
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Affiliation(s)
- Jenny C A Read
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom.,
| | | | - Toby S Wood
- School of Mathematics, Statistics & Physics, Newcastle University, Newcastle upon Tyne, UK.,
| | - Bing Wu
- Quantified Experience, Magic Leap Inc, Plantation, FL, USA.,
| | | | - Clifton M Schor
- Herbert Wertheim School of Optometry and Vision Science, University of California at Berkeley, Berkeley, CA, USA.,
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17
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The role of retinotopic cues in deciphering the direction and magnitude of monocular dynamic ocular accommodation: A review. Vision Res 2022; 196:108026. [DOI: 10.1016/j.visres.2022.108026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 02/04/2022] [Accepted: 02/10/2022] [Indexed: 12/28/2022]
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18
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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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19
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Barbero S, Bradley A, López-Gil N, Rubinstein J, Thibos L. Catastrophe optics theory unveils the localised wave aberration features that generate ghost images. Ophthalmic Physiol Opt 2022; 42:1074-1091. [PMID: 35620968 PMCID: PMC9543491 DOI: 10.1111/opo.13008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 12/19/2022]
Abstract
Monocular polyplopia (ghost or multiple images) is a serious visual impediment for some people who report seeing two (diplopia), three (triplopia) or even more images. Polyplopia is expected to appear if the point spread function (PSF) has multiple intensity cores (a dense concentration of a large portion of the radiant flux contained in the PSF) relatively separated from each other, each of which contributes to a distinct image. We present a theory that assigns these multiple PSF cores to specific features of aberrated wavefronts, thereby accounting optically for the perceptual phenomenon of monocular polyplopia. The theory provides two major conclusions. First, the most likely event giving rise to multiple PSF cores is the presence of hyperbolic, or less probably elliptical, umbilic caustics (using the terminology of catastrophe optics). Second, those umbilic caustics formed on the retinal surface are associated with certain points of the wave aberration function, called cusps of Gauss, where the gradient of a curvature function vanishes. However, not all cusps of Gauss generate those umbilic caustics. We also provide necessary conditions for those cusps of Gauss to be fertile. To show the potential of this theoretical framework for understanding the nature and origin of polyplopia, we provide specific examples of ocular wave aberration functions that induce diplopia and triplopia. The polyplopia effects in these examples are illustrated by depicting the multi-core PSFs and the convolved retinal images for clinical letter charts, both through computer simulations and through experimental recording using an adaptive optics set-up. The number and location of cores in the PSF is thus a potentially useful metric for the existence and severity of polyplopia in spatial vision. These examples also help explain why physiological pupil constriction might reduce the incidence of ghosting and multiple images of daily objects that affect vision with dilated pupils. This mechanistic explanation suggests a possible role for optical phase-masking as a clinical treatment for polyplopia and ghosting.
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Affiliation(s)
| | - Arthur Bradley
- School of Optometry, Indiana University, Bloomington, Indiana, USA
| | - Norberto López-Gil
- Instituto Universitario de Investigación en Envejecimiento, Universidad de Murcia, Murcia, Spain
| | | | - Larry Thibos
- School of Optometry, Indiana University, Bloomington, Indiana, USA
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20
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Li S, Tang A, Yang B, Wang J, Liu L. Virtual reality-based vision therapy versus OBVAT in the treatment of convergence insufficiency, accommodative dysfunction: a pilot randomized controlled trial. BMC Ophthalmol 2022; 22:182. [PMID: 35448970 PMCID: PMC9027290 DOI: 10.1186/s12886-022-02393-z] [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: 09/21/2021] [Accepted: 04/11/2022] [Indexed: 02/08/2023] Open
Abstract
Background Virtual reality is being increasingly applied in vision therapy. However, the differences in effectiveness, optimal treatment cycle, and prognosis between virtual reality-based vision therapy and traditional therapies remain unknown. The purpose of this study was to compare the effectiveness of virtual reality-based vision therapy and office-based vergence/accommodative therapy in young adults with convergence insufficiency or accommodative dysfunction. Methods The patients were randomly assigned to either the virtual reality-based vision therapy group or the office-based vergence/accommodative therapy group. The vision therapy lasted 12 weeks (1 h/week) in both groups. Binocular visual functions (vergence and accommodation) were measured and a subjective questionnaire-based assessment was performed at baseline and after 6 and 12 weeks of therapy. Results In total, 33 patients with convergence insufficiency and 30 with accommodative dysfunction completed the study. After 12 weeks of treatment for convergence insufficiency, the Convergence Insufficiency Symptom Survey score (F2,31 = 13.704, P < 0.001), near point of convergence (F2,31 = 21.774, P < 0.001), positive fusional vergence (F2,31 = 71.766, P < 0.001), and near horizontal phoria (F2,31 = 16.482, P < 0.001) improved significantly in both groups. Moreover, the monocular accommodative amplitude (F2,25 = 22.154, P < 0.001) and monocular accommodative facility (F2,25 = 86.164, P < 0.001) improved significantly in both groups after 12 weeks of treatment. A statistically significant difference was observed in monocular accommodative facility (F1,25 = 8.140, P = 0.009) between the two groups, but not in other vergence and accommodative functions (0.098 < P < 0.687). Conclusion Virtual reality-based vision therapy significantly improved binocular vision functions and symptoms in patients with convergence insufficiency and accommodative dysfunction, thereby suggesting its effectiveness as a new optional or additional treatment for young adults with these conditions. Trial registration This study was registered at the Chinese Clinical Trials Registry on 16/04/2019 (identifier: ChiCTR1900022556). Supplementary Information The online version contains supplementary material available at 10.1186/s12886-022-02393-z.
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Affiliation(s)
- Shijin Li
- Department of Optometry, West China Clinical Medical College, Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Angcang Tang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Bi Yang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Jianglan Wang
- Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China
| | - Longqian Liu
- Department of Optometry, West China Clinical Medical College, Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China. .,Department of Ophthalmology, West China Hospital of Sichuan University, 37 Guoxue Xiang, Chengdu, Sichuan Province, China.
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21
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Gil A, Hernández CS, Nam AS, Varadaraj V, Durr NJ, Lim D, Dave SR, Lage E. Predicting subjective refraction with dynamic retinal image quality analysis. Sci Rep 2022; 12:3714. [PMID: 35260664 PMCID: PMC8904625 DOI: 10.1038/s41598-022-07786-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 02/22/2022] [Indexed: 01/13/2023] Open
Abstract
The aim of this work is to evaluate the performance of a novel algorithm that combines dynamic wavefront aberrometry data and descriptors of the retinal image quality from objective autorefractor measurements to predict subjective refraction. We conducted a retrospective study of the prediction accuracy and precision of the novel algorithm compared to standard search-based retinal image quality optimization algorithms. Dynamic measurements from 34 adult patients were taken with a handheld wavefront autorefractor and static data was obtained with a high-end desktop wavefront aberrometer. The search-based algorithms did not significantly improve the results of the desktop system, while the dynamic approach was able to simultaneously reduce the standard deviation (up to a 15% for reduction of spherical equivalent power) and the mean bias error of the predictions (up to 80% reduction of spherical equivalent power) for the handheld aberrometer. These results suggest that dynamic retinal image analysis can substantially improve the accuracy and precision of the portable wavefront autorefractor relative to subjective refraction.
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Affiliation(s)
- Andrea Gil
- Department of Electronics and Communications Technology, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, Spain.,PlenOptika, Inc., Boston, MA, USA
| | - Carlos S Hernández
- Department of Electronics and Communications Technology, Universidad Autónoma de Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, Spain.,PlenOptika, Inc., Boston, MA, USA
| | | | - Varshini Varadaraj
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nicholas J Durr
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Eduardo Lage
- Department of Electronics and Communications Technology, Universidad Autónoma de Madrid, Madrid, Spain. .,Instituto de Investigación Sanitaria Fundación Jiménez Díaz, Madrid, Spain. .,PlenOptika, Inc., Boston, MA, USA.
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22
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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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23
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Li L, Zhang B, Wang Z. Comparison of accommodation and accommodative micro-fluctuation after implantable collamer lens and LASIK surgery for myopia. BMC Ophthalmol 2022; 22:8. [PMID: 34983448 PMCID: PMC8725356 DOI: 10.1186/s12886-021-02217-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 12/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To longitudinally analyze and compare the accommodative micro-fluctuation (MFs) and accommodative function between myopic patients after implantable collamer lens (ICL) implantation and laser in situ keratomileusis (LASIK). METHODS Patients with good corrected visual acuity (20/20 or better) and underwent ICL (V4c) and LASIK for myopic-correction (ranging from - 3.50 to - 8.50 D) were recruited. Refraction, amplitude of accommodation (AMP), accommodative lag, higher-order aberration (HOA), and MFs were recorded before surgery and 1 and 3 months after surgery. The ACOMEREF automatic refractor was used to measure the high-frequency component (HFC) of the MFs, which suggested tension of the ciliary muscle. RESULTS The study comprised 120 eyes. At 3 months after surgery, the manifest refractive spherical equivalent of the ICL and LASIK groups were - 0.11 and - 0.09 D, respectively (p = 0.46). HFC values were significantly higher at 1 month (p = 0.03) and 3 months postoperatively (p = 0.03) in the ICL group compared to that in the LASIK group. The ocular HOA of the ICL group was 1.08 ± 0.43 μm, which was lower than the LASIK group 1.45 ± 0.54 μm (p = 0.01). No significant differences in AMP and accommodative lag between groups were noted at 3 months postoperatively. There was a positive correlation between HFC and vault of the ICL lens (r2 = 0.14, p = 0.005). There were no correlations between HFC and ocular HOA and postoperative MRSE in the two groups (all p>0.05). CONCLUSIONS The HFC increased significantly after an early period of ICL implantation compared to laser in situ keratomileusis for myopic correction, which indicated increased tension of the ciliary muscle, and had a positive correlation on the vault of the ICL lens; However, studies with longer follow-up time and more structural evaluation are needed.
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Affiliation(s)
- Li Li
- Aier School of Ophthalmology, Central South University, Fourth Floor, New Century Mansion, 198 Middle Furong Road, Changsha, China.,Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Guangzhou, China.,Chongqing Eye and Vision Care Hospital, Chongqing, China.,Aier Institute of Refractive Surgery, Aier Eye Hospital Group, Changsha, China
| | - Bo Zhang
- Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Guangzhou, China.,Aier Institute of Refractive Surgery, Aier Eye Hospital Group, Changsha, China
| | - Zheng Wang
- Aier School of Ophthalmology, Central South University, Fourth Floor, New Century Mansion, 198 Middle Furong Road, Changsha, China. .,Department of Refractive Surgery, Guangzhou Aier Eye Hospital, Guangzhou, China. .,Aier Institute of Refractive Surgery, Aier Eye Hospital Group, Changsha, China.
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Romashchenko D, Papadogiannis P, Unsbo P, Lundström L. Simultaneous measurements of foveal and peripheral aberrations with accommodation in myopic and emmetropic eyes. BIOMEDICAL OPTICS EXPRESS 2021; 12:7422-7433. [PMID: 35003843 PMCID: PMC8713693 DOI: 10.1364/boe.438400] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 06/14/2023]
Abstract
The difference in peripheral retinal image quality between myopic and emmetropic eyes plays a major role in the design of the optical myopia interventions. Knowing this difference under accommodation can help to understand the limitations of the currently available optical solutions for myopia control. A newly developed dual-angle open-field sensor was used to assess the simultaneous foveal and peripheral ( 20 ∘ nasal visual field) wavefront aberrations for five target vergences from -0.31 D to -4.0 D in six myopic and five emmetropic participants. With accommodation, the myopic eyes showed myopic shifts, and the emmetropic eyes showed no change in RPR. Furthermore, RPR calculated from simultaneous measurements showed lower intra-subject variability compared to the RPR calculated from peripheral measurements and target vergence. Other aberrations, as well as modulation transfer functions for natural pupils, were similar between the groups and the accommodation levels, foveally and peripherally. Results from viewing the same nearby target with and without spectacles by myopic participants suggest that the accommodative response is not the leading factor controlling the amplitude of accommodation microfluctuations.
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Affiliation(s)
- Dmitry Romashchenko
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
- Current address: R&D, Johnson & Johnson Vision, Groningen, 9728 NX, The Netherlands
| | - Petros Papadogiannis
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
| | - Peter Unsbo
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
| | - Linda Lundström
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
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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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Reduction in Accommodative Response of Schoolchildren by a Double-Mirror System. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18199951. [PMID: 34639251 PMCID: PMC8508213 DOI: 10.3390/ijerph18199951] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/13/2021] [Accepted: 09/21/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE This study first proposed the application of a double-mirror system (DMS) to extend viewing distance and investigate the accommodative response of schoolchildren under a DMS. METHOD Fifty-seven subjects aged between 7 and 12 years old were recruited in this study, and the experiment was divided into two stages. The first stage consisted of a case history inquiry, a refraction state, and a visual function examination. In the second stage, the subjects gazed at an object at distances of 0.4 m, 2.285 m, and through a DMS, respectively, and their accommodative responses were measured using an open-field autorefractor. RESULTS There was no significant difference in the schoolchildren's accommodative response between subjects gazing at an object at 2.285 m (0.14 ± 0.35 D, p > 0.05) and those gazing at it through a DMS (0.20 ± 0.35 D). However, their accommodative response showed a significant difference between subjects gazing at an object at 0.4 m and 2.285 m and those gazing at it at 0.4 m and through a DMS. CONCLUSION In this experiment, the results of the children's accommodative response measured at 2.285 m or through a DMS are very similar. The viewing distance can be extended by a DMS, resulting in accommodative relaxation. This result may have potential applications in myopia control.
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Di Claudio ED, Giannitrapani P, Jacovitti G. Predicting blur visual discomfort for natural scenes by the loss of positional information. Vision Res 2021; 189:33-45. [PMID: 34530308 DOI: 10.1016/j.visres.2021.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 07/14/2021] [Accepted: 07/30/2021] [Indexed: 12/22/2022]
Abstract
The perception of blur due to accommodation failures, insufficient optical correction or imperfect image reproduction is a common source of visual discomfort, usually attributed to an anomalous and annoying distribution of the image spectrum in the spatial frequency domain. In the present paper, this discomfort is related to a loss of the localization accuracy of the observed patterns. It is assumed, as a starting perceptual principle, that the visual system is optimally adapted to pattern localization in a natural environment. Thus, since the best possible accuracy of the image patterns localization is indicated by the positional Fisher Information, it is argued that blur discomfort is strictly related to a loss of this information. Following this concept, a receptive field functional model is adopted to predict the visual discomfort. It is a complex-valued operator, orientation-selective both in the space domain and in the spatial frequency domain. Starting from the case of Gaussian blur, the analysis is extended to a generic type of blur by applying a positional Fisher Information equivalence criterion. Out-of-focus blur and astigmatic blur are presented as significant examples. The validity of the proposed model is verified by comparing its predictions with subjective ratings. The model fits linearly with the experiments reported in independent databases, based on different protocols and settings.
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Affiliation(s)
- Elio D Di Claudio
- Dept. of Information Engineering, Electronics and Telecommunications (DIET), University of Rome "La Sapienza", via Eudossiana 18, I-00184 Rome, Italy
| | - Paolo Giannitrapani
- Dept. of Information Engineering, Electronics and Telecommunications (DIET), University of Rome "La Sapienza", via Eudossiana 18, I-00184 Rome, Italy.
| | - Giovanni Jacovitti
- Retired, formerly with DIET, University of Rome "La Sapienza", via Eudossiana 18, I-00184 Rome, Italy
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Águila-Carrasco AJD, Marín-Franch I. Predictability of sinusoidally moving stimuli does not improve the accuracy of the accommodative response. Sci Rep 2021; 11:15195. [PMID: 34312461 PMCID: PMC8313575 DOI: 10.1038/s41598-021-94642-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 07/13/2021] [Indexed: 12/31/2022] Open
Abstract
Previous research work suggests that predictable target motion such as sinusoidal movement can be anticipated by the visual system, thereby improving the accommodative response. The validity of predictable motion for studying human dynamic accommodation is sometimes put into question. The aim of this work was to assess the effect of anticipation along with learning (and motivation, etc.) and fatigue (and boredom, loss of attention, etc.) on dynamic accommodation experiments from a practical perspective. Specifically, changes in amplitude and temporal phase lag were estimated within and between trials as 9 adult observers were instructed to focus on a stimulus that oscillated sinusoidally towards and away from the eye at specific temporal frequencies. On average, amplitude decreased whereas phase increased within trials. No evidence of anticipation or learning was observed either within or between trials. Fatigue consistently dominated anticipation and learning within the course of each trial. Even if the eye is equipped by a prediction operator as it is often assumed, fatigue confounds the results from dynamic accommodation experiments more than anticipation or learning.
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Labhishetty V, Cholewiak SA, Roorda A, Banks MS. Lags and leads of accommodation in humans: Fact or fiction? J Vis 2021; 21:21. [PMID: 33764384 PMCID: PMC7995353 DOI: 10.1167/jov.21.3.21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The focusing response of the human eye — accommodation — exhibits errors known as lags and leads. Lags occur when the stimulus is near and the eye appears to focus farther than the stimulus. Leads occur with far stimuli where the eye appears to focus nearer than the stimulus. We used objective and subjective measures simultaneously to determine where the eye is best focused. The objective measures were made with a wavefront sensor and an autorefractor, both of which analyze light reflected from the retina. These measures exhibited typical accommodative errors, mostly lags. The subjective measure was visual acuity, which of course depends not only on the eye's optics but also on photoreception and neural processing of the retinal image. The subjective measure revealed much smaller errors. Acuity was maximized at or very close to the distance of the accommodative stimulus. Thus, accommodation is accurate in terms of maximizing visual performance.
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Affiliation(s)
- Vivek Labhishetty
- Optometry & Vision Science, University of California, Berkeley, CA, USA., https://www.researchgate.net/profile/Vivek_Labhishetty
| | - Steven A Cholewiak
- Optometry & Vision Science, University of California, Berkeley, CA, USA., http://steven.cholewiak.com
| | - Austin Roorda
- Optometry & Vision Science, University of California, Berkeley, CA, USA., http://roorda.vision.berkeley.edu
| | - Martin S Banks
- Optometry & Vision Science, University of California, Berkeley, CA, USA., http://bankslab.berkeley.edu
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Molina R, Redondo B, Molina-Carballo A, García JA, Muñoz-Hoyos A, Vera J, Jiménez R. Capturing attention improves accommodation: An experimental study in children with ADHD using multiple object tracking. Vision Res 2021; 186:52-58. [PMID: 34051609 DOI: 10.1016/j.visres.2021.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 05/13/2021] [Accepted: 05/13/2021] [Indexed: 11/15/2022]
Abstract
The present study was aimed at assessing the impact of manipulating the attentional load using a multiple object tracking (MOT) task on the dynamics of the accommodative response in children with attention deficit hyperactivity disorder (ADHD). The pupil size was recorded to assess the effectiveness of the experimental manipulation, and the role of ADHD medication was also explored. The accommodative and pupil dynamics (magnitude and variability) were monitored with an open-field autorefractometer (WAM-5500) in 41 children with ADHD (24 non-medicated and 17 medicated) and 21 non-ADHD controls, while they performed the MOT task with four different levels of complexity (i.e., tracking zero, one, two, or three targets). We found that increasing the attentional load caused a heightened accommodative response, showing a negative association between MOT complexity and accommodative lag in children with ADHD and non-ADHD controls. Complementarily, the pupil size increased as a function of task complexity, confirming a successful experimental manipulation. The stability of accommodation was insensitive to the attentional manipulation, but it differed between groups. Specifically, non-medicated children with ADHD exhibited a greater variability of accommodation in comparison to controls. Increasing the attentional load is associated with a reduction in the accommodative lag in children with ADHD and controls. Our findings show that the allocation of attention plays an important role in the dynamics of the accommodative response, which may be of relevance in the diagnosis and treatment of accommodative deficits in children with and without ADHD.
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Affiliation(s)
- Rubén Molina
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Beatriz Redondo
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Spain.
| | - Antonio Molina-Carballo
- Faculty of Medicine, University of Granada, Neuropediatric and Neurodevelopment Unit of Clinico San Cecilio University Hospital, Spain
| | - José Antonio García
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Antonio Muñoz-Hoyos
- Faculty of Medicine, University of Granada, Neuropediatric and Neurodevelopment Unit of Clinico San Cecilio University Hospital, Spain
| | - Jesús Vera
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Raimundo Jiménez
- CLARO (Clinical and Laboratory Applications of Research in Optometry) Research Group, Department of Optics, Faculty of Sciences, University of Granada, Spain
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Ntodie M, Saunders KJ, Little JA. Correction of Low-Moderate Hyperopia Improves Accommodative Function for Some Hyperopic Children During Sustained Near Work. Invest Ophthalmol Vis Sci 2021; 62:6. [PMID: 33821881 PMCID: PMC8039472 DOI: 10.1167/iovs.62.4.6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Purpose This study investigated whether refractive correction improved accommodative function of hyperopic children while engaged in two sustained near activities. Methods Sustained accommodative function of 63 participants (aged 5–10 years) with varying levels of uncorrected hyperopia (>/= +1.00 D and < + 5.00 D spherical equivalent in the least hyperopic eye) was measured using eccentric infrared photorefraction (PowerRef 3; PlusOptix, Germany). Binocular accommodation measures were recorded while participants engaged in 2 tasks at 25 cm for 15 minutes each: an “active” task (reading small print on an Amazon Kindle), and a “passive” task (watching an animated movie on liquid crystal display [LCD] screen). Participants also underwent a comprehensive visual assessment, including measurement of presenting visual acuity, prism cover test, and stereoacuity. Reading speed was assessed with and without hyperopic correction. Refractive error was determined by cycloplegic retinoscopy. Results Hyperopic refractive correction significantly improved accuracy of accommodative responses in both task (pairwise comparisons: t = −3.70, P = 0.001, and t = −4.93, P < 0.001 for reading and movie tasks, respectively). Accommodative microfluctuations increased with refractive correction in the reading task (F(1,61) = 25.77, P < 0.001) but decreased in the movie task (F(1,59) = 4.44, P = 0.04). Reading speed also significantly increased with refractive correction (F(1,48) = 66.32, P < 0.001). Conclusions Correcting low-moderate levels of hyperopia has a positive impact on accommodative performance during sustained near activity in some schoolchildren. For these children, prescribing hyperopic correction may benefit performance in near vision tasks.
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Affiliation(s)
- Michael Ntodie
- Optometry and Vision Science Department, School of Allied Health Sciences, College of Health, University of Cape Coast, Cape Coast, Ghana.,Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - Kathryn J Saunders
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
| | - Julie-Anne Little
- Centre for Optometry and Vision Science, Biomedical Sciences Research Institute, Ulster University, Coleraine, United Kingdom
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Bharadwaj SR, Roy S, Satgunam P. Spasm of Near Reflex: Objective Assessment of the Near-Triad. Invest Ophthalmol Vis Sci 2021; 61:18. [PMID: 32663291 PMCID: PMC7425728 DOI: 10.1167/iovs.61.8.18] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose To characterize binocular steady-state accommodation, pupil and convergence responses (near triad) in spasm of near reflex (SNR) before and after optical and pharmacological intervention. To identify the putative source of SNR in the neural control schema of accommodation-vergence interaction using controls-engineering modeling. Methods Near-triad of 15 patients with SNR (9 to 23 years) was recorded using an infrared photorefractor at 2m viewing distance for 120s during clinical presentation, after optical fogging intended to relieve spasm, with cycloplegia, post-cycloplegia and long-term follow-up visits. Data were also collected without cycloplegia in 15 age-matched controls. Schor (1999) model was used to computationally simulate accommodation and vergence responses of controls and SNR. Results Both eyes of SNR exhibited significant myopia and refraction fluctuations (<1.0Hz) during clinical presentation [median (25th to 75th IQR) refraction: −1.7D (−3.2 to −0.8D); root mean squared (RMS) deviation: 1.1D (0.5 to 1.5D)], relative to controls [0.8D (−0.03 to 1.4D); 0.2D (0.1 to 0.3D)] (p < 0.001). These decreased after optical fogging, largely eliminated with cycloplegia and partially re-appeared in the post-cycloplegia and follow-up visits. SNR responses could be modeled by increasing the gain and decay time of tonic accommodation, vis-à-vis, controls. Pupil and convergence responses in SNR were similar to controls at all visits (p > 0.1). Conclusions Exaggerated fluctuations of steady-state accommodation may be a signature feature of SNR, even while their pupil and convergence responses may remain unaffected. These fluctuations may arise from the tonic accommodation controller, the properties of which could be potentially altered after optical fogging to relieve the disorder.
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The Effects of Chewing Gum in Preventing Eyestrain. BIOMED RESEARCH INTERNATIONAL 2020; 2020:2470473. [PMID: 33274199 PMCID: PMC7683129 DOI: 10.1155/2020/2470473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 12/26/2022]
Abstract
Purpose To investigate the effects of chewing gum and tablet candy to reduce eyestrain in healthy individuals. Materials and Methods A double-blinded crossover trial was conducted. Forty-six healthy individuals (23 men, 23 women) between 20 and 59 years old, feeling eyestrain, were enrolled. Each 10-year age group included 12 individuals except the 30s group, which included 10 individuals. A visual task was performed on reading material displayed on a computer screen at a fixed distance for 60 min. Gum or tablet candy of two pieces were chewed for two 15-min periods starting 15 and 45 min after starting to read. Subjects chewed gum on Day 1 and tablet candy on Day 2, and vice versa. Primary outcome is as follows: subjective eye fatigue (eye tiredness, eye heaviness, blurred vision, double vision, and eye dryness) using a visual analog scale (VAS). Secondary outcomes are as follows: subjective accommodation from near and far points of accommodation measured with a D'ACOMO, spherical equivalent refraction, and eye dryness by analyzing ring break-up time (RBUT) measured with the RT-7000 Auto Ref-Topographer. Results The VAS scores of subjective eye fatigue were not significantly changed between chewing gum and tablet candy (P = 0.397 − P = 0.909). Those scores of eye tiredness and eye heaviness were significantly longer before and after the visual task with tablet candy (P = 0.013 and P = 0.025, respectively) but not with chewing gum. The changes of subjective accommodation were significantly lower after the visual task between chewing gum and candy (P = 0.043). There were significant differences among each age group (20 s vs. 30 s, P = 0.594; 20 s vs. 40 s, P = 0.002; 20 s vs. 50 s, P = 0.002). After reading, the changes of spherical equivalent refraction did not indicate a shift toward myopia (P = 0.267). In the RBUT, there were no significant differences between the samples (P = 0.680). Conclusions Chewing gum helps improve the ability of the eye to focus, especially in young adults.
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Redondo B, Vera J, Ortega-Sánchez A, Molina R, Jiménez R. Effects of a blue-blocking screen filter on accommodative accuracy and visual discomfort. Ophthalmic Physiol Opt 2020; 40:790-800. [PMID: 33001489 DOI: 10.1111/opo.12738] [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: 05/13/2020] [Accepted: 08/28/2020] [Indexed: 02/06/2023]
Abstract
INTRODUCTION The prescription of blue-blocking (B-B) filters for the management of visual symptoms and signs associated with the use of electronic devices is routinely performed by eye care specialists. However, the utility of B-B filters is a matter of debate and discussion by the scientific community due to the lack of evidence supporting their use. Here, we aimed to determine the effects of using B-B filters on the dynamics of the accommodative response and pupil size and perceived levels of visual discomfort, while performing a 30-min reading task at a close distance in subjects who routinely use electronic devices. METHODS Nineteen healthy young adults (22.0 ± 2.7 years) read two 30-min passages on a computer screen placed at 50 cm, either while using a commercially available B-B filter or without any filter on two different days. The magnitude and variability of both the accommodative response and pupil size were dynamically measured for 60 s using the WAM-5500 open field autorefractometer at 4-5, 9-10, 14-15, 19-20, 24-25, and 29-30 min into the trial. The perceived levels of visual discomfort were also obtained. RESULTS The lag and variability of accommodation were insensitive to the blue light level (p = 0.34 and 0.62, respectively). There was a time-on-task effect for the variability of accommodation, showing greater instability over time regardless of the blue light level. The use of the B-B filter was associated with improved reading speed (p = 0.02), with an increase of 16.5 words per minute. However, it was not associated with any significant change in pupil dynamics or the perceived levels of visual discomfort (p> 0.05 in both cases). CONCLUSIONS Our data showed that the use of a B-B filter had no effect on accommodative dynamics or visual symptomatology. Based on these findings, there is no support for the prescription of B-B filters to attenuate the visual symptoms and signs associated with the use of electronic devices in healthy young adults.
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Affiliation(s)
| | - Jesús Vera
- Department of Optics, University of Granada, Granada, Spain
| | | | - Rubén Molina
- Department of Optics, University of Granada, Granada, Spain
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Abstract
Since Kepler (1604) and Descartes (1637), 'vergence' (the angular rotation of the eyes) has been thought of as one of our most important absolute distance cues. But vergence has never been tested as an absolute distance cue divorced from obvious confounding cues such as binocular disparity. In this article, we control for these confounding cues for the first time by gradually manipulating vergence and find that observers fail to accurately judge distance from vergence. We consider several different interpretations of these results and argue that the most principled response to these results is to question the general effectiveness of vergence as an absolute distance cue. Given that other absolute distance cues (such as motion parallax and vertical disparities) are limited in application, this poses a real challenge to our contemporary understanding of visual scale.
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Affiliation(s)
- Paul Linton
- Centre for Applied Vision Research, City, University of London, Northampton Square, Clerkenwell, London, EC1V 0HB, UK.
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Romashchenko D, Lundström L. Dual-angle open field wavefront sensor for simultaneous measurements of the central and peripheral human eye. BIOMEDICAL OPTICS EXPRESS 2020; 11:3125-3138. [PMID: 32637246 PMCID: PMC7316022 DOI: 10.1364/boe.391548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/29/2020] [Accepted: 05/03/2020] [Indexed: 05/31/2023]
Abstract
We have developed a novel dual-angle open field wavefront sensor. This device captures real-time foveal and peripheral Zernike aberrations, while providing natural binocular viewing conditions for the subjects. The simultaneous data recording enables accurate analysis of changes in ocular optics with accommodation overcoming any uncertainties caused by accommodative lag or lead. The instrument will be used in myopia research to study central and peripheral ocular optics during near work and to investigate the effects of optical myopia control interventions. Proof of concept measurements, performed on an artificial eye model and on 3 volunteers, showed good repeatability with foveal-peripheral data synchronization of 65 msec or better. The deviations from subjective cycloplegic refractions were not more than 0.31 D. Furthermore, we tested the dual-angle wavefront sensor in two novel measurement schemes: (1) focusing on a close target, and (2) accommodation step change.
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Affiliation(s)
- Dmitry Romashchenko
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
| | - Linda Lundström
- Department of Applied Physics, Royal Institute of Technology, Stockholm, 11421, Sweden
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Redondo B, Vera J, Molina R, Davies LN, Jiménez R. Accommodative dynamics and attention: the influence of manipulating attentional capacity on accommodative lag and variability. Ophthalmic Physiol Opt 2020; 40:510-518. [DOI: 10.1111/opo.12690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/27/2020] [Accepted: 03/31/2020] [Indexed: 01/31/2023]
Affiliation(s)
| | - Jesús Vera
- Department of Optics University of Granada Granada Spain
| | - Rubén Molina
- Department of Optics University of Granada Granada Spain
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Accommodative response in children with attention deficit hyperactivity disorder (ADHD): the influence of accommodation stimulus and medication. Graefes Arch Clin Exp Ophthalmol 2020; 258:1299-1307. [DOI: 10.1007/s00417-020-04645-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/05/2020] [Accepted: 03/04/2020] [Indexed: 12/14/2022] Open
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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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Danielewska ME, Messner A, Werkmeister RM, Placek MM, Aranha Dos Santos V, Rękas M, Schmetterer L. Relationship Between the Parameters of Corneal and Fundus Pulse Signals Acquired With a Combined Ultrasound and Laser Interferometry Technique. Transl Vis Sci Technol 2019; 8:15. [PMID: 31388467 PMCID: PMC6675519 DOI: 10.1167/tvst.8.4.15] [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: 02/10/2019] [Accepted: 06/10/2019] [Indexed: 01/16/2023] Open
Abstract
Purpose To estimate the relationship between the characteristics of the corneal pulse (CP) signal and those of the fundus pulse (FP) signal measured with a combined noncontact ultrasonic and laser interferometry technique in healthy subjects. Methods Twenty-two healthy subjects participated in experiments that included measurements of intraocular pressure, ocular pulse amplitude, ocular biometry, blood pressure, and heart rate. Additionally, simultaneous recordings of CP and FP signals were acquired with a noncontact ultrasonic device combined with laser interferometry. Subsequently, ocular perfusion pressure (OPP) and the time and spectral parameters of CP and FP signals were computed. A system model was proposed to relate the FP signal to the CP signal. Results The system model revealed that the eye globe transfers information between signals of the posterior and anterior eye, relatively amplifying higher spectral harmonics. The amplitude of the second CP harmonic is predicted by FPRMS and OPP (R2 = 0.468, P = 0.002). Partial correlation analysis showed that the CP signal parameters are statistically significantly correlated with those of the FP signal and OPP, after correcting for age and sex. Conclusions The eye globe can be viewed as a high pass filter, in which the CP characteristic changes in relation to the fundus pulsation. The FP signal and OPP have an impact on the variations of the CP signal morphology. Translational Relevance Investigation of differences between the characteristics of the anterior and posterior tissue movements is a promising method for evaluating the role of circulatory and biomechanical components in the pathophysiology of ocular diseases.
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Affiliation(s)
- Monika E Danielewska
- Wrocław University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław, Poland
| | - Alina Messner
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Michał M Placek
- Wrocław University of Science and Technology, Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wrocław, Poland
| | | | - Marek Rękas
- Department of Ophthalmology, Military Institute of Medicine, Warsaw, Poland
| | - Leopold Schmetterer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
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41
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Caffeine alters the dynamics of ocular accommodation depending on the habitual caffeine intake. Exp Eye Res 2019; 185:107663. [DOI: 10.1016/j.exer.2019.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 05/06/2019] [Accepted: 05/08/2019] [Indexed: 11/23/2022]
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42
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Dynamics of the accommodative response under artificially-induced aniseikonia. Exp Eye Res 2019; 185:107674. [DOI: 10.1016/j.exer.2019.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 02/01/2023]
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Effects of Optical Correction Method on the Magnitude and Variability of Accommodative Response: A Test-retest Study. Optom Vis Sci 2019; 96:568-578. [DOI: 10.1097/opx.0000000000001406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Del Águila-Carrasco AJ, Kruger PB, Lara F, López-Gil N. Aberrations and accommodation. Clin Exp Optom 2019; 103:95-103. [PMID: 31284325 DOI: 10.1111/cxo.12938] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 12/26/2022] Open
Abstract
Modern methods of measuring the refractive state of the eye include wavefront sensors which make it possible to monitor both static and dynamic changes of the ocular wavefront while the eye observes a target positioned at different distances away from the eye. In addition to monitoring the ocular aberrations, wavefront refraction methods allow measurement of the accommodative response while viewing with the eye's habitual chromatic and monochromatic aberrations present, with these aberrations removed, and with specific aberrations added or removed. A large number of experiments describing the effects of accommodation on aberrations and vice versa are reviewed, pointing out the implications for fundamental questions related to the mechanism of accommodation.
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Affiliation(s)
| | - Philip B Kruger
- College of Optometry, The State University of New York, New York, NY, USA
| | - Francisco Lara
- Vision Science Research Group (CiViUM), Instituto Universitario de Investigación en Envejecimiento (IUIE), University of Murcia, Murcia, Spain
| | - Norberto López-Gil
- Vision Science Research Group (CiViUM), Instituto Universitario de Investigación en Envejecimiento (IUIE), University of Murcia, Murcia, Spain
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Bartuzel MM, Robert Iskander D, Marín-Franch I, López-Gil N. Defocus vibrations in optical systems-considerations in reference to the human eye. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2019; 36:464-470. [PMID: 30874183 DOI: 10.1364/josaa.36.000464] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
Experimental visual acuity (VA) of eight subjects was measured using the Freiburg vision test in a custom-made adaptive optics system. Measurements were conducted under one control and five defocus-induced conditions. In the defocus-induced conditions, 1 diopter of myopic defocus was added to the system using the Badal stage, and defocus vibrations with five different levels of amplitude were generated by a deformable mirror at 50 Hz. Computational simulations of the visual Strehl ratio (VSOTF) were performed using average aberrations of each subject recorded in the control condition. For the first time, to the best of our knowledge, it has been shown experimentally that both the simulated VSOTF and experimentally measured VA improve when defocus vibrations are added to a defocused eye.
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Domínguez-Vicent A, Monsálvez-Romín D, Esteve-Taboada JJ, Montés-Micó R, Ferrer-Blasco T. Effect of age in the ciliary muscle during accommodation: Sectorial analysis. JOURNAL OF OPTOMETRY 2019; 12:14-21. [PMID: 29627301 PMCID: PMC6318550 DOI: 10.1016/j.optom.2018.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/02/2018] [Accepted: 01/02/2018] [Indexed: 06/02/2023]
Abstract
PURPOSE To compare changes in the ciliary muscle area at different sectors between pre-presbyopic and presbyopic eyes during accommodation by means of an anterior segment optical coherence tomographer (OCT). METHODS The anterior ciliary muscle area was measured in 20 healthy and phakic pre-presbyopic eyes, whose mean age was 23.3±4.4 years, and in 20 healthy and phakic presbyopic eyes, whose mean age was 46.5±5.2 years. The relative change in the cross-sectional area of the ciliary muscle was measured at the nasal, inferior, and temporal sectors between 0 and -3 D of vergence, in -1 D step. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. RESULTS Each population group showed a significant increase in the anterior ciliary muscle area for each sector. The maximum increase in the ciliary muscle area within the pre-presbyopic group was about 30%, and for the presbyopic one was about 25%. At the same time, it was obtained that the larger the vergence, the larger the variability. Furthermore, the linear model showed a positive tendency between the change in the ciliary muscle area of each sector and the vergence for both population groups, which coefficient of determination was in all cases greater than 0.93. CONCLUSION The anterior ciliary muscle area tends to increase with accommodation. The presbyopic nasal, inferior, and temporal ciliary muscle seem to have the same contractile capability as the young presbyopic ciliary muscle. These results might help to increase the evidences in the knowledge regarding the modern understanding of accommodation biometry and biomechanics.
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Affiliation(s)
| | | | - José J Esteve-Taboada
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
| | - Robert Montés-Micó
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
| | - Teresa Ferrer-Blasco
- Department of Optics and Optometry and Vision Sciences, University of Valencia, Spain
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Labhishetty V, Bobier WR, Lakshminarayanan V. Is 25Hz enough to accurately measure a dynamic change in the ocular accommodation? JOURNAL OF OPTOMETRY 2019; 12:22-29. [PMID: 29580938 PMCID: PMC6318547 DOI: 10.1016/j.optom.2018.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 02/09/2018] [Accepted: 02/13/2018] [Indexed: 06/01/2023]
Abstract
BACKGROUND Accommodation is often recorded at a low sampling rate using devices such as autorefractors that are designed to measure the static refractive error. It is therefore important to determine if that resolution is sufficient to accurately measure the dynamic properties of accommodation. The current study provides both theoretical and empirical evidence on the ideal sampling rate necessary to measure a dynamic response. METHODS Accommodative and disaccommodative step stimuli ranging from 1-3D (1D steps) were presented using a Badal optical system. Responses from 12 children (8-13 years) and 6 adults (20-35 years) were recorded using a dynamic photorefractor (DPR). Fast Fourier transformation was applied to the unsmoothed dynamic responses including position, velocity and acceleration. Also, velocity and acceleration main sequence (MS) characteristics were compared between three photorefractor conditions on 3 subjects. RESULTS The Nyquist sampling limit necessary to accurately estimate position, velocity and acceleration was at least 5, 10 and 70Hz, respectively. Peak velocity and acceleration were significantly underestimated at a lower rate (p<0.5). However, the slope of MS remained invariant with sampling rate (p>0.5). CONCLUSION Contrary to the previous findings, a dynamic accommodative response exhibited frequencies larger than 10Hz. Stimulus direction and amplitude had no influence on the frequencies present in the dynamic response. Peak velocity and acceleration can be significantly underestimated when sampled at a lower rate. Taken as a whole, low sampling rate instruments can accurately estimate static accommodation, however, caution needs to be exercised when using them for dynamic accommodation.
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Affiliation(s)
- Vivek Labhishetty
- School of Optometry and Vision Science, University of Waterloo, ON, Canada.
| | - William R Bobier
- School of Optometry and Vision Science, University of Waterloo, ON, Canada
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Labhishetty V, Chakraborty A, Bobier WR. Is blur sensitivity altered in children with progressive myopia? Vision Res 2018; 154:142-153. [PMID: 30472331 DOI: 10.1016/j.visres.2018.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 12/25/2022]
Abstract
School aged children with progressive myopia show large accommodative lags to blur only cue which is suggestive of a large depth of focus (DOF). While DOF measures are lacking in this age group, their blur detection and discrimination capacities appear to be similar to their non-myopic peers. Accordingly, the current study quantified DOF and blur detection ability in progressive myopic children showing large accommodative lags compared to their non-myopic peers and adults. Blur sensitivity measures were taken from 12 children (8-13 years, 6 myopes and 6 emmetropes) and 6 adults (20-35 years). DOF was quantified using step changes in the lens induced defocus while the subjects viewed a high contrast target through a Badal lens at either 2 or 4D demand. Blur detection thresholds (BDT) were tested using a similar high contrast target in a 2-alternate forced-choice paradigm (2AFC) at both the demands. In addition to the large accommodative lags, micro fluctuations and DOF were significantly larger in myopic children compared to the other groups. However, BDTs were similar across the three groups. When limited to blur cues, the findings of a large DOF coupled with large response lags suggests that myopes are less sensitive to retinal defocus. However, in agreement to a previous study, refractive error had no influence on their BDTs suggesting that the reduced sensitivity to the defocus in a myopic eye appears to be compensated by some form of an adjustment in the higher visual processes to preserve the subjective percept even with a poor retinal image quality.
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Affiliation(s)
- Vivek Labhishetty
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada.
| | - Arijit Chakraborty
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada
| | - William R Bobier
- School of Optometry and Vision Science, University of Waterloo, Waterloo, ON N2L3G1, Canada
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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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50
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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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