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Finch AP, Fernandez-Alonso M, Kirby AK, Read JCA, Love GD. Focusing on mixed narrow band stimuli: Implications for mechanisms of accommodation and displays. J Vis 2024; 24:14. [PMID: 39302649 PMCID: PMC11421670 DOI: 10.1167/jov.24.9.14] [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: 11/06/2023] [Accepted: 06/19/2024] [Indexed: 09/22/2024] Open
Abstract
The eye has considerable chromatic aberration, meaning that the accommodative demand varies with wavelength. Given this, how does the eye accommodate to light of differing spectral content? Previous work is not conclusive but, in general, the eye focuses in the center of the visible spectrum for broadband light, and it focuses at a distance appropriate for individual wavelengths for narrowband light. For stimuli containing two colors, there are also mixed reports. This is the second of a series of two papers where we investigate accommodation in relation to chromatic aberration Fernandez-Alonso, Finch, Love, and Read (2024). In this paper, for the first time, we measure how the eye accommodates to images containing two narrowband wavelengths, with varying relative luminance under monocular conditions. We find that the eye tends to accommodate between the two extremes, weighted by the relative luminance. At first sight, this seems reasonable, but we show that image quality would be maximized if the eye instead accommodated on the more luminous wavelength. Next we explore several hypotheses as to what signal the eye might be using to drive accommodation and compare these with the experimental data. We show that the data is best explained if the eye seeks to maximize contrast at low spatial frequencies. We consider the implication of these results for both the mechanism behind accommodation, and for modern displays containing narrowband illuminants.
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Affiliation(s)
| | - Maydel Fernandez-Alonso
- Biosciences Institute, Newcastle University, Newcastle, UK, Present address: Max Planck Institute for Biological Cybernetics, Germany
| | | | - Jenny C A Read
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Gordon D Love
- School of Computer Science, University of Leeds, Leeds, UK
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Richards J, Jaskulski M, Rickert M, Kollbaum P. Digital device viewing behaviour in children. Ophthalmic Physiol Opt 2024; 44:546-553. [PMID: 38379462 DOI: 10.1111/opo.13288] [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: 12/13/2023] [Revised: 01/24/2024] [Accepted: 02/02/2024] [Indexed: 02/22/2024]
Abstract
INTRODUCTION Habitual viewing behaviour is widely believed to be an important contributing factor to the onset and progression of myopia and may be task dependent. The purpose of this study was to quantify the habitual viewing distance of children performing five different tasks on a smartphone digital device. METHODS The real-time viewing distance in 38 children with their habitual correction was measured using software (MyopiaApp) on a handheld (Google Pixel 3) device. Five tasks were performed in a randomised sequence: playing a game, watching video in a light (680 lux) and dark (5.5 lux) environment and reading small (8 pt) and large (16 pt) text. ANCOVA statistical analysis was used to evaluate the effect of task, group (myope vs. non-myope) and arm length on the median relative viewing distance. RESULTS Arm length was not correlated with viewing distance in any of the tasks, and there was no significant difference in viewing distance between any of the tasks. Specifically, a two-way mixed ANCOVA indicated that task, refractive group (myopic vs. non-myopic), age and arm length, as well as all two-way interactions were not significantly associated with viewing distance. Overall, 60% of the total variance in viewing distance was accounted for by individual differences. CONCLUSIONS The average handheld viewing distance was similar across a variety of everyday tasks in a representative sample of myopic and emmetropic children. Neither arm length, age nor refractive group were associated with viewing distance in any of the tasks. Importantly, myopic children of a given size did not hold the smartphone digital device at a different distance for any task than their equally sized non-myopic peers. However, both groups exhibited high inter-individual variability in mean viewing distance, indicating some subjects performed all tasks at further distances while other subjects used at nearer distances.
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Affiliation(s)
- Josh Richards
- Indiana University School of Optometry, Bloomington, Indiana, USA
| | - Matt Jaskulski
- Indiana University School of Optometry, Bloomington, Indiana, USA
- VisionApp Solutions S.L., Murcia, Spain
| | - Martin Rickert
- Indiana University School of Optometry, Bloomington, Indiana, USA
| | - Pete Kollbaum
- Indiana University School of Optometry, Bloomington, Indiana, USA
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Bamdad S, Momeni-Moghaddam H, Abdolahian M, Piñero DP. Agreement of wavefront-based refraction, dry and cycloplegic autorefraction with subjective refraction. JOURNAL OF OPTOMETRY 2022; 15:100-106. [PMID: 32896507 PMCID: PMC8712579 DOI: 10.1016/j.optom.2020.08.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/07/2020] [Accepted: 08/17/2020] [Indexed: 05/26/2023]
Abstract
PURPOSE To evaluate the agreement of dry, and cycloplegic autorefraction and wavefront-based refraction with subjective refraction. METHOD 83 subjects aged 19-57 years were included in this cross-sectional study. Refractive status was determined using four methods including subjective refraction, wavefront-based refraction, dry and cycloplegic autorefraction. Refractive data were recorded as sphere, cylinder and spherical equivalent (SE). Power vector components were used to compare the astigmatism obtained using the different methods of refraction. RESULTS The more negative spherical, cylindrical and SE components were obtained using dry autorefraction, wavefront-based refraction and dry autorefraction, respectively. The less negative spherical, cylindrical and SE components were obtained using cycloplegic autorefraction, subjective refraction and cycloplegic autorefraction, respectively. Considering the spherical component, there was a statistically significant hyperopic shift (0.12 ± 0.29 D, p = 0.001) with cycloplegic autorefraction and a significant myopic shift (-0.17 ± 0.32 D, p < 0.001) with dry autorefraction compared to subjective refraction, while the difference between wavefront-based and subjective refraction was not significant statistically (p = 0.145). The calculated cylindrical component using subjective refraction showed statistically significant difference with dry auto-refraction (p < 0.001), cycloplegic auto-refraction (p = 0.041) and wavefront refraction (p < 0.001). The highest correlation with subjective refraction in sphere, cylinder and SE was observed for cycloplegic auto-refraction (rs = 0.967), dry auto-refraction (rs = 0.983) and cycloplegic auto-refraction (rs = 0.982), respectively. CONCLUSIONS As subjective refraction is gold standard in our study, sphere in cycloplegic auto-refraction and astigmatism in dry auto-refraction showed better agreement and correlation.
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Affiliation(s)
- Shahram Bamdad
- Poostchi Ophthalmology Research Center, Shiraz University Of Medical Sciences, Shiraz, Iran
| | - Hamed Momeni-Moghaddam
- Health Promotion Research Center, Zahedan University of Medical Sciences, Zahedan, Iran; Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Milad Abdolahian
- Poostchi Ophthalmology Research Center, Shiraz University Of Medical Sciences, Shiraz, Iran.
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
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Gatinel D, Malet J, Dumas L, Azar DT. Comparison of Low Degree/High Degree and Zernike Expansions for Evaluating Simulation Outcomes After Customized Aspheric Laser Corrections. Transl Vis Sci Technol 2021; 10:21. [PMID: 34003958 PMCID: PMC7991963 DOI: 10.1167/tvst.10.3.21] [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: 11/25/2022] Open
Abstract
Purpose The purpose of this study was to compare the low degree/high degree (LD/HD) and Zernike Expansion simulation outcomes evaluating the corneal wavefront changes after theoretical conventional and customized aspheric photorefractive ablations. Methods Initial anterior corneal surface profiles were modeled as conic sections with pre-operative apical curvature, R0, and asphericity, Q0. Postoperative apical curvature, R1, was computed from intended defocus correction, D, diameter zone, S, and target postoperative asphericity, Q1. Coefficients of both Zernike and LD/HD polynomial expansions of the rotationally symmetrical corneal profile were computed using scalar products. We modeled different values of D, R0, Q0, S, and ΔQ = Q1 to Q0. The corresponding postoperative changes in defocus (Δz20 vs. Δg20), fourth order (Δz40 vs. Δg40) and sixth order (Δz60 vs. Δg60) Zernike and LD/HD spherical aberrations (SAs) were compared. In addition, retrospective clinical data and wavefront measurements were obtained from two examples of two patient eyes before and after corneal laser photoablation. Results The z20, varied with both R0 and Q0, whereas the LD/HD defocus coefficient, g20, was relatively robust to changes in asphericity. Variations of apical curvature better correlated with defocus and ΔQ with SA coefficients in the LD/HD classification. The impact of ΔQ was null on g20 but induced significant linear variations in z20 and fourth order SA coefficients. LD/HD coefficients provided a good correlation with the visual performances of the operated eyes. Conclusions Simulated variations in postoperative corneal profile and wavefront expansion using the LD/HD approach showed good correlations between defocus and asphericity variations with variations in corneal curvature and SA coefficients, respectively. Translational Relevance The relevance of this study was to provide a clinically relevant alternative to Zernike polynomials for the interpretation of wavefront changes after customized aspheric corrections.
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Affiliation(s)
- Damien Gatinel
- Department of Anterior Segment and Refractive Surgery, Rothschild Ophthalmic Foundation Hospital, Paris, France
| | - Jacques Malet
- Department of Anterior Segment and Refractive Surgery, Rothschild Ophthalmic Foundation Hospital, Paris, France
| | - Laurent Dumas
- Laboratoire de Mathématiques de Versailles, UVSQ, CNRS, Université Paris-Saclay, Versailles, France
| | - Dimitri T Azar
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago College of Medicine, Chicago, IL, USA
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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: 20] [Impact Index Per Article: 6.7] [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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Almutairi MS, Altoaimi BH, Bradley A. Impact of monovision on dynamic accommodation of early presbyopes. Ophthalmic Physiol Opt 2019; 40:47-59. [PMID: 31879995 DOI: 10.1111/opo.12660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 11/24/2019] [Accepted: 11/29/2019] [Indexed: 01/13/2023]
Abstract
PURPOSE To examine the impact of monovision on dynamic changes in accommodation, pupil responses, spherical aberration and resultant image quality in early presbyopes. METHODS Refractive state, pupil size and spherical aberration levels were monitored in nine early presbyopes who exhibited some accommodation (40-50 years, mean = 42 ± 2.37 years) using a Shack-Hartmann aberrometer as a binocularly viewed stimulus stepped closer (from 2 m to 40 cm), or farther (from 40 cm to 2 m). Comparison data from two fully presbyopic (i.e. non-accommodating) subjects (ages 46 and 61 years) and two young adults (ages 26 and 29 years) were also collected. Each subject was fit with four different refractive strategies: (1) both eyes corrected for 2 m, (2) both eyes corrected for 40 cm, (3) monovision with the measured right eye corrected for 2 m and, (4) monovision with the right eye corrected for 40 cm. Monochromatic image quality was quantified using the AreaMTF metric. RESULTS When fit with monovision, the largest number of early presbyopes produce an accommodative response dominated by the right eye correction (distance or near) as the stimulus is abruptly changed from the retinal conjugate plane of one eye to that of the other eye. However, the accommodative responses in some early presbyopes were always dominated by the distance corrected eye, the near corrected eye, or by convergence. When the stimulus approached, the near corrected eye experienced high image quality only if there was no accommodative response. However, reduced image quality was observed if an accommodative response was initiated. Neither accommodation nor pupil response latencies were longer with monovision corrections compared with bilateral distance corrections (p > 0.05). In the early presbyopes, spherical aberration was reduced during near viewing, but primarily due to pupil miosis and not lens shape changes. CONCLUSION As the stimulus was abruptly changed from the retinal conjugate plane of the distance corrected eye to that of the near corrected eye, most early presbyopes fit with monovision accommodated, which resulted in a decline, not an increase in image quality in the near corrected eye. These results reveal a non-optimal accommodative strategy in early presbyopes fit with monovision.
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Affiliation(s)
- Meznah S Almutairi
- Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.,School of Optometry, Indiana University, Bloomington, USA
| | - Basal H Altoaimi
- Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Arthur Bradley
- School of Optometry, Indiana University, Bloomington, USA
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Cheng X, Xu J, Brennan NA. Accommodation and its role in myopia progression and control with soft contact lenses. Ophthalmic Physiol Opt 2019; 39:162-171. [PMID: 30994197 DOI: 10.1111/opo.12614] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/18/2019] [Indexed: 11/26/2022]
Abstract
PURPOSE To examine the impact of contact lens optical design on accommodative behaviour of children and the correlation between myopia progression and the accommodative response of the eye while wearing a contact lens designed for myopia control. METHODS A post-hoc analysis was conducted on data from a previously published myopia control trial. A total of 109 subjects (aged 8 to 11 years, myopia: -0.75 to -4.00 D) wore either a Control (single-vision, n = 57) or a Test (with positive spherical aberration, +SA, n = 52) soft contact lens, binocularly for 1 year. Accommodative response was measured as the subject observed targets at -1.00 to -4.00 D vergence using the Grand Seiko WAM-5500 open-field autorefractor (www.grandseiko.com). Slope of accommodative response (SAR) as well as distance and near phoria and stimulus accommodative convergence/accommodation (AC/A) were compared between each group at baseline without study lenses and at 1-week and 1-year visits with study lenses. The SAR was also compared to changes in axial length (AL) and spherical equivalent cycloplegic auto refraction (SECAR). RESULTS At baseline, there was no significant difference in SAR between the two study groups (ΔSAR = -0.039, p = 0.84). At 1 week, mean SAR of the Test group was significantly less than for the Control group (ΔSAR = -0.203, p < 0.0001), an effect that persisted to 1 year (ΔSAR = -0.129, p < 0.0001). In the Test group, greater SAR was associated with less change in AL (regression coefficient: -0.59 mm, p < 0.0001) and SECAR (regression coefficient: 1.12 D, p = 0.006) at 1 year. In the Control group, associations between SAR and change in AL and SECAR were not statistically significant. Compared to the Control group, eyes of the Test group appeared to be more exophoric with study lenses, however, the difference between the two groups was only significant at 1 week for distance phoria and 1 year for near phoria. CONCLUSION The soft contact lens with +SA for controlling myopia progression resulted in an apparent decrease in mean accommodation. Within the Test group, reduced accommodative response correlated with greater myopia progression, suggesting some subjects in the Test group utilised the +SA for near viewing, inducing hyperopic defocus at the retina. Accordingly, the potential impact of a lens optics on accommodative function should be considered during design of myopia control lenses.
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Affiliation(s)
- Xu Cheng
- Johnson & Johnson Vision, Jacksonville, Florida, USA
| | - Jing Xu
- Johnson & Johnson Vision, Jacksonville, Florida, USA
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Wolffsohn JS, Kollbaum PS, Berntsen DA, Atchison DA, Benavente A, Bradley A, Buckhurst H, Collins M, Fujikado T, Hiraoka T, Hirota M, Jones D, Logan NS, Lundström L, Torii H, Read SA, Naidoo K. IMI - Clinical Myopia Control Trials and Instrumentation Report. Invest Ophthalmol Vis Sci 2019; 60:M132-M160. [PMID: 30817830 DOI: 10.1167/iovs.18-25955] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The evidence-basis based on existing myopia control trials along with the supporting academic literature were reviewed; this informed recommendations on the outcomes suggested from clinical trials aimed at slowing myopia progression to show the effectiveness of treatments and the impact on patients. These outcomes were classified as primary (refractive error and/or axial length), secondary (patient reported outcomes and treatment compliance), and exploratory (peripheral refraction, accommodative changes, ocular alignment, pupil size, outdoor activity/lighting levels, anterior and posterior segment imaging, and tissue biomechanics). The currently available instrumentation, which the literature has shown to best achieve the primary and secondary outcomes, was reviewed and critiqued. Issues relating to study design and patient selection were also identified. These findings and consensus from the International Myopia Institute members led to final recommendations to inform future instrumentation development and to guide clinical trial protocols.
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Affiliation(s)
- James S Wolffsohn
- Ophthalmic Research Group, Aston University, Birmingham, United Kingdom
| | - Pete S Kollbaum
- Indiana University, School of Optometry, Bloomington, Indiana, United States
| | - David A Berntsen
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - David A Atchison
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | | | - Arthur Bradley
- Indiana University, School of Optometry, Bloomington, Indiana, United States
| | - Hetal Buckhurst
- School of Health Professions, Peninsula Allied Health Centre, Plymouth University, Plymouth, United Kingdom
| | - Michael Collins
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | - Takashi Fujikado
- Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Takahiro Hiraoka
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Masakazu Hirota
- Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Debbie Jones
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Nicola S Logan
- Ophthalmic Research Group, Aston University, Birmingham, United Kingdom
| | | | - Hidemasa Torii
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Scott A Read
- School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Australia
| | - Kovin Naidoo
- African Vision Research Institute, University of KwaZulu-Natal, Durban, South Africa
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Small-pupil versus multifocal strategies for expanding depth of focus of presbyopic eyes. J Cataract Refract Surg 2019; 45:647-655. [DOI: 10.1016/j.jcrs.2019.01.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 12/28/2018] [Accepted: 01/09/2019] [Indexed: 11/23/2022]
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Otero C, Aldaba M, Pujol J. Clinical evaluation of an automated subjective refraction method implemented in a computer-controlled motorized phoropter. JOURNAL OF OPTOMETRY 2019; 12:74-83. [PMID: 30389250 PMCID: PMC6449872 DOI: 10.1016/j.optom.2018.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/30/2018] [Accepted: 09/17/2018] [Indexed: 06/08/2023]
Abstract
PURPOSE To investigate a new algorithm to perform an automated non-cycloplegic refraction in adults. METHODS Fifty healthy subjects were measured twice (test-retest) with the new automated subjective refraction method and with the conventional clinician subjective refraction procedure. Objective refraction was also measured with the Grand Seiko WAM-5500 autorefractor. The new automated method was inspired on the root finding bisection algorithm and on the Euclidean distances in the power vector domain. The algorithm was implemented in a computer that was synchronized with a customized motorized phoropter. Repeatability was mainly assessed with the within-subject standard deviation (Sw) and accuracy was mainly assessed with the limits of agreement. RESULTS The within-subject standard deviations of the power vector components (M, J0, J45) obtained for the right eye are (±0.13, ±0.04, ±0.05)D and (±0.17, ±0.03, ±0.07)D, respectively, for the clinical and the automated subjective refraction methods. The limits of agreement (with the clinical method) for the automated and the objective methods are, respectively (±0.56, ±0.18, ±0.31)D and (±0.77, ±0.15, ±0.18)D. Similar results are obtained for the left eye. CONCLUSIONS The proposed automated method is repeatable and more accurate than objective techniques in healthy adults. However, it is not accurate enough to replace the clinical subjective refraction yet and it should be tested in a wider population in terms of age, refraction and different ocular conditions. Despite these important limitations, this method has been shown to be a potentially valuable method to improve the access to primary eye care services in developing countries.
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Affiliation(s)
- Carles Otero
- Vision and Eye Research Unit, School of Medicine, Anglia Ruskin University, Cambridge, UK; Center for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Terrassa, Spain.
| | - Mikel Aldaba
- Center for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Terrassa, Spain
| | - Jaume Pujol
- Center for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Terrassa, Spain
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Putnam NM, Vasudevan B, Juarez A, Le CT, Sam K, de Gracia P, Hoppert A. Comparing habitual and i. Scription refractions. BMC Ophthalmol 2019; 19:49. [PMID: 30755182 PMCID: PMC6373049 DOI: 10.1186/s12886-019-1053-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 01/29/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Many patients voice concerns regarding poor night vision, even when they see 20/20 or better in the exam room. During mesopic and scotopic conditions the pupil size increases, increasing the effects on visual performance of uncorrected (residual) refractive errors. The i.Scription refraction method claims to optimize traditional refractions for mesopic and scotopic conditions, by using the information that the Zeiss i.Profilerplus gathers of ocular aberrations (low and high order). The aim of this study was to investigate any differences between habitual and i.Scription refractions and their relationship to night vision complaints. METHODS Habitual, subjective, and i.Scription refractions were obtained from both eyes of eighteen subjects. Low and high order aberrations of the subjects were recorded with the Zeiss i.Profilerplus. The root mean square (RMS) metric was calculated for small (3 mm) and maximum pupil sizes. Subjects rated their difficulty with driving at night on a scale of 1-10. RESULTS There was a statistically significant difference between the habitual and i.Scription refractions on both the sphere and cylinder values [(t = 3.12, p < 0.01), (t = 5.39, p < 0.01)]. The same was found when comparing the subjective and i.Scription refractions [(t = 2.31, p = 0.03), (t = 2.54, p = 0.02)]. There were no significant differences found when comparing the sphere and cylinder values between the habitual and subjective refractions or on any combination of spherical equivalent refraction. The maximum pupil size of the subject population on this study, measured with the i.Profilerplus, was 4.8 ± 1.04 mm. Ten out of the eighteen subjects had discomfort at night with an average magnitude of 4 ± 2.7. Ratings of difficulty with night vision correlated with the change in spherical equivalent correction between the habitual and i.Scription refractions (p = 0.01). A sub-analysis of myopic subjects (n = 15) showed an increase in the significance of this relationship (p = 0.002). CONCLUSIONS The i.Scription method improves night vision by correcting the sphere and cylinder more precisely. There was a correlation between the amount of change in the cylinder value between habitual and i.Scription prescriptions and the magnitude of the reported visual discomfort at night.
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Affiliation(s)
- Nicole M. Putnam
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Balamurali Vasudevan
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Andre Juarez
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Cam Tu Le
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Kristine Sam
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Pablo de Gracia
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
| | - Allissun Hoppert
- Midwestern University, College of Optometry, 19555 N 59th Ave, Glendale, Arizona 85308 USA
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Gatinel D, Malet J, Dumas L. Polynomial decomposition method for ocular wavefront analysis. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2018; 35:2035-2045. [PMID: 30645293 DOI: 10.1364/josaa.35.002035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Zernike circle polynomials are in widespread use for wavefront analysis because of their orthogonality over a circular pupil and their representation of balanced classical aberrations. However, some of the higher-order modes contain linear and quadratic terms. A new aberration series is proposed to better separate the low- versus higher-order aberration components. Because its higher-order modes are devoid of linear and quadratic terms, our new basis can be used to better fit the low- and higher-order components of the wavefront. This new basis may quantify the aberrations more accurately and provide clinicians with coefficient magnitudes which better underline the impact of clinically significant aberration modes.
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Abstract
SIGNIFICANCE When fit with monovision, most early presbyopes (aged 40 to 50 years) accommodated to near objects by focusing the distance corrected eye, leaving the near corrected eye myopically defocused with reduced image quality. A few were able to switch focus to the near corrected eye retaining a consistently focused image in one eye over a wider range of distances. PURPOSE The aim of this study was to examine accommodation behavior, pupil responses, and resultant image quality of early presbyopes fit with either bilateral or unilateral (monovision) near adds. METHODS Accommodative response and pupil size of 19 subjects (27 to 60 years), including 13 early presbyopes (40 to 50 years), were measured using an aberrometer as a binocularly viewed 20/40 letter E was moved from 2 m to 20 cm. Each subject was fit with different refractive strategies: bilateral distance correction, bilateral +2 diopters (D) near add, and unilateral +2 D near add placed over the measured right eye or unmeasured left eye. Monochromatic image quality was quantified using the Visual Strehl ratio metric. RESULTS With bilateral +2 D near add, all early presbyopes mostly refrained from accommodating (gain = 0.22 D/D) until the target approached closer than the 50-cm far point, and they then accommodated accurately until their maximum accommodative amplitude was reached. With monovision, most (10 of 13 early presbyopes) accommodated to focus the distance corrected eye, leaving the near corrected eye myopically defocused with reduced image quality. As stimulus distance became closer than their distance corrected eye's near point, they continued to exert maximum accommodation. Only two early presbyopes relaxed their accommodation to "switch" focus to the near corrected eye as target distance was reduced, and these two did not experience bilateral drop in image quality as stimulus distance became closer than the near point of the distance corrected eye. CONCLUSIONS Our data suggest that many early presbyopes will not initially adopt an accommodation strategy that optimizes image quality with monovision, but consistently accommodate to focus the distance corrected eye.
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Marín-Franch I, Xu R, Bradley A, Thibos LN, López-Gil N. The effect of spherical aberration on visual performance and refractive state for stimuli and tasks typical of night viewing. JOURNAL OF OPTOMETRY 2018; 11:144-152. [PMID: 29292240 PMCID: PMC6039613 DOI: 10.1016/j.optom.2017.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/12/2017] [Accepted: 10/13/2017] [Indexed: 06/07/2023]
Abstract
PURPOSE The aim of this work was to examine the impact of Seidel spherical aberration (SA) on optimum refractive state for detecting and discriminating small bright lights on a dark background. METHODS An adaptive-optics system was used to correct ocular aberrations of cyclopleged eyes and then systematically introduce five levels of Seidel SA for a 7-mm diameter pupil: 0,±0.18, and±0.36diopters (D)mm-2. For each level of SA, subjects were required to detect one or resolve two points of light (0.54 arc min diameter) on a dark background. Refractive error was measured by adjusting stimulus vergence to minimize detection and resolution thresholds. Two other novel focusing tasks for single points of light required maximizing the perceived intensity of a bright point's core and minimizing its overall perceived size (i.e. minimize starburst artifacts). Except for the detection task, luminance of the point of light was 1000cdm-2 on a black background lower than 0.5cdm-2. RESULTS Positive SA introduced myopic shifts relative to the best subjective focus for dark letters on a bright background when there was no SA, whereas negative SA introduced hyperopic shifts in optimal focus. The changes in optimal focus were -1.7, -2.4, -2.0, and -9.2D of focus per Dmm-2 of SA for the detection task, resolution task, and maximization of core's intensity and minimization of size, respectively. CONCLUSION Ocular SA can be a significant contributor to changes in refractive state when viewing high-contrast point sources typically encountered in nighttime environments.
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Affiliation(s)
- Iván Marín-Franch
- Department of Ophthalmology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA; Instituto Universitario de Investigación en Envejecimiento, Universidad de Murcia, 30100 Murcia, Spain.
| | - Renfeng Xu
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Arthur Bradley
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Larry N Thibos
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Norberto López-Gil
- Instituto Universitario de Investigación en Envejecimiento, Universidad de Murcia, 30100 Murcia, Spain
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Xu R, Kollbaum P, Thibos L, Lopez-Gil N, Bradley A. Reducing starbursts in highly aberrated eyes with pupil miosis. Ophthalmic Physiol Opt 2017; 38:26-36. [PMID: 29265469 DOI: 10.1111/opo.12420] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/21/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE To test the hypothesis that marginal ray deviations determine perceived starburst sizes, and to explore different strategies for decreasing starburst size in highly aberrated eyes. METHODS Perceived size of starburst images and visual acuities were measured psychophysically for eyes with varying levels of spherical aberration, pupil sizes, and defocus. Computationally, we use a polychromatic eye model including the typical levels of higher order aberrations (HOAs) for keratoconic and post-LASIK eyes to quantify the image quality (the visually weighted Strehl ratio derived from the optical transfer function, VSOTF) with different pupil sizes at both photopic and mesopic light levels. RESULTS For distance corrected post-LASIK and keratoconic eyes with a night-time pupil (e.g., 7 mm), the starburst diameter is about 1.5 degrees (1 degree for normal presbyopic eyes), which can be reduced to ≤0.25 degrees with pupil sizes ≤3 mm. Starburst size is predicted from the magnitude of the longitudinal spherical aberration. Refracting the eye to focus the pupil margin also removed starbursts, but, unlike small pupils, significantly degraded visual acuity. Reducing pupil diameter to 3 mm improved image quality for these highly aberrated eyes by about 2.7 × to 1.7 × relative to the natural pupils when light levels were varied from 0.1 to 1000 cd m-2 , respectively. CONCLUSION Subjects with highly aberrated eyes observed larger starbursts around bright lights at night predictable by the deviated marginal rays. These were effectively attenuated by reducing pupil diameters to ≤3 mm, which did not cause a drop in visual acuity or modelled image quality even at mesopic light levels.
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Affiliation(s)
- Renfeng Xu
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Pete Kollbaum
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Larry Thibos
- School of Optometry, Indiana University, Bloomington, IN, USA
| | | | - Arthur Bradley
- School of Optometry, Indiana University, Bloomington, IN, USA
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New Objective Refraction Metric Based on Sphere Fitting to the Wavefront. J Ophthalmol 2017; 2017:1909348. [PMID: 29104804 PMCID: PMC5632459 DOI: 10.1155/2017/1909348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/09/2017] [Accepted: 07/11/2017] [Indexed: 11/17/2022] Open
Abstract
Purpose To develop an objective refraction formula based on the ocular wavefront error (WFE) expressed in terms of Zernike coefficients and pupil radius, which would be an accurate predictor of subjective spherical equivalent (SE) for different pupil sizes. Methods A sphere is fitted to the ocular wavefront at the center and at a variable distance, t. The optimal fitting distance, topt, is obtained empirically from a dataset of 308 eyes as a function of objective refraction pupil radius, r0, and used to define the formula of a new wavefront refraction metric (MTR). The metric is tested in another, independent dataset of 200 eyes. Results For pupil radii r0 ≤ 2 mm, the new metric predicts the equivalent sphere with similar accuracy (<0.1D), however, for r0 > 2 mm, the mean error of traditional metrics can increase beyond 0.25D, and the MTR remains accurate. The proposed metric allows clinicians to obtain an accurate clinical spherical equivalent value without rescaling/refitting of the wavefront coefficients. It has the potential to be developed into a metric which will be able to predict full spherocylindrical refraction for the desired illumination conditions and corresponding pupil size.
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Accommodative Behavior of Eyes Wearing Aspheric Single Vision Contact Lenses. Optom Vis Sci 2017; 94:971-980. [DOI: 10.1097/opx.0000000000001121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Liquid Crystal Spatial Light Modulators for Simulating Zonal Multifocal Lenses. Optom Vis Sci 2017; 94:867-875. [DOI: 10.1097/opx.0000000000001108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Xu R, Wang H, Thibos LN, Bradley A. Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2017; 34:481-492. [PMID: 28375317 DOI: 10.1364/josaa.34.000481] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1 cd/m2, and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5 cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image quality remain throughout the photopic and mesopic ranges. However, restricting pupils to <2 mm will cause significant reductions in the best focus vision at low photopic and mesopic luminances.
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Almutairi MS, Altoaimi BH, Bradley A. Accommodation and pupil behaviour of binocularly viewing early presbyopes. Ophthalmic Physiol Opt 2017; 37:128-140. [DOI: 10.1111/opo.12356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/04/2017] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Arthur Bradley
- School of Optometry; Indiana University; Bloomington USA
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23
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Aldaba M, Otero C, Pujol J, Atchison DA. Does the Badal optometer stimulate accommodation accurately? Ophthalmic Physiol Opt 2016; 37:88-95. [DOI: 10.1111/opo.12334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/26/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Mikel Aldaba
- Davalor Research Center (DRC); Universitat Politècnica de Catalunya; Terrassa Spain
- Centre for Sensors, Instruments, and Systems Development (CD6); Universitat Politecnica de Catalunya (UPC); Terrassa Spain
| | - Carles Otero
- Davalor Research Center (DRC); Universitat Politècnica de Catalunya; Terrassa Spain
- Centre for Sensors, Instruments, and Systems Development (CD6); Universitat Politecnica de Catalunya (UPC); Terrassa Spain
| | - Jaume Pujol
- Davalor Research Center (DRC); Universitat Politècnica de Catalunya; Terrassa Spain
- Centre for Sensors, Instruments, and Systems Development (CD6); Universitat Politecnica de Catalunya (UPC); Terrassa Spain
| | - David A. Atchison
- Institute of Health & Biomedical Innovation and School of Optometry & Vision Science; Queensland University of Technology; Kelvin Grove Australia
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Xu R, Bradley A, López Gil N, Thibos LN. Modelling the effects of secondary spherical aberration on refractive error, image quality and depth of focus. Ophthalmic Physiol Opt 2016; 35:28-38. [PMID: 25532544 DOI: 10.1111/opo.12185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/21/2014] [Indexed: 11/28/2022]
Abstract
PURPOSE To examine the role of Zernike secondary spherical aberration and its component terms on refraction, image quality and depth of focus. METHODS Computational methods were used to define wavefronts with controlled levels of r(6) , r(4) and r(2) terms, and image quality associated with these terms for a range of target vergences. Target vergences that generated maximum image quality were used as an objective measures of refractive error. RESULTS Unlike primary Zernike spherical aberration, which generates peak image quality with a near paraxial focus, in the absence of other higher order aberrations, peak image quality with secondary spherical aberration is achieved with a near marginal focus. When alone, positive primary and secondary spherical aberration induce small hyperopic shifts in refraction, but in the presence of other higher order aberrations, secondary spherical aberration can induce significant myopic shifts in refractive error, as predicted by the combined lower order r(4) & r(2) component of Z60. The predicted expansion in depth of focus associated with increased primary or secondary spherical aberration is mostly absent if a strict image quality criterion is applied. The expansion of depth of focus observed with a low image quality criterion when opposite sign Z40 and Z60 are combined is primarily due to the elevated r(4) term. CONCLUSIONS Secondary Zernike spherical aberration can have a significant impact on refractive error, image quality and depth of focus, but mostly due to the lower order components within this polynomial. Our analysis shows that the r(6) term that defines secondary spherical aberration actually narrows rather than expands depth of focus, when in the presence of the r(4) term within Z60. Therefore, a multifocal lens generated with exclusively primary spherical aberration is likely to be more effective than one that includes opposite sign of primary and secondary spherical aberration.
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Affiliation(s)
- Renfeng Xu
- School of Optometry, Indiana University, Bloomington, USA
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Bernal-Molina P, Castejón-Mochón JF, Bradley A, López-Gil N. Focus correction in an apodized system with spherical aberration. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:1556-1563. [PMID: 26367299 DOI: 10.1364/josaa.32.001556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We performed a theoretical and computational analysis of the through-focus axial irradiance in a system with a Gaussian amplitude pupil function and fourth- and sixth-order spherical aberration (SA). Two cases are analyzed: low aberrated systems, and the human eye containing significant levels of SA and a natural apodization produced by the Stiles-Crawford effect. Results show that apodization only produces a refraction change of the plane that maximized the Strehl ratio for eyes containing significant levels of negative SA.
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Abstract
PURPOSE We evaluate the effect of pupil size on objectively measured amplitude of accommodation (AA). METHODS Pupil diameter and wavefront aberrometry were obtained in 15 eyes when stimulus swept across the range of clear vision in steps of 0.5 diopters. Wavefront refraction techniques were used to compute objective AA as the maximum refractive change. Measurements were obtained monocularly under low and high ambient room lighting conditions with a fixed luminance of the fixation target. Amplitude of accommodation computations were performed taking into account just paraxial rays (paraxial AA) or including the effects of the change of spherical aberration during accommodation (minRMS AA). RESULTS Mean pupil size values at low light level were 6.26 mm (relaxed) and 4.15 mm (maximum accommodation), whereas at the high light level, those values became 4.74 and 3.04 mm, respectively. The effects of both light level on accommodation were significant (p < 0.001), and accommodative miosis was slightly larger at low light levels. Mean minRMS and paraxial AA were always greater by more than 1 diopter in high than in low ambient lighting conditions (p < 0.01), indicating a significant impact of pupil size on AA. CONCLUSIONS The influence of the ambient lighting on the objective AA is not only attributed to the increased effects of spherical aberration as the pupil dilates but mostly attributed to a decrease in the paraxial accommodation as pupil dilates.
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Abstract
PURPOSE To determine if measurement of monochromatic wavefront aberrations in near-infrared light can accurately and precisely predict subjective refractive error for polychromatic light. Our approach requires knowledge of the monochromatic wavelength-in-focus (WiF) when polychromatic light is well focused, for which new empirical measurements are reported. METHODS With accommodation paralyzed, subjective refractive error was measured as a function of wavelength using a Badal optometer by optimally focusing a letter chart illuminated with monochromatic or white light (color temperature, 4575 K). Wavelength-in-focus was determined by interpolation as that wavelength for which monochromatic refractive error matches white light refractive error. The population-based mean value of WiF, used in conjunction with the Indiana Eye model of chromatic aberration, corrected for monochromatic (842 nm) estimates of refractive error obtained from wavefront aberration measurements, predicts the absolute refractive error of individual eye for polychromatic light for comparison with empirical measurements. RESULTS Average WiF for eight subjects was 569 nm (SE = 3.6 nm) for a 3-mm pupil and 575 nm (SE = 3.0 nm) for an 8-mm pupil. For small (3 mm) pupils, the mean (±SD) error in predicting refractive error for white light was 0.20 (±0.05) diopters (D) (range, +0.70 to -0.46 D), and for large (>8 mm) pupils, the mean (±SD) prediction error was 0.004 (±0.12) D (range, +0.56 to -0.52 D). The population mean of prediction errors was statistically not different from zero for large pupils but was slightly hyperopic for small pupils. CONCLUSIONS Subjective refractive error for white light can be accurately and precisely predicted objectively from monochromatic wavefront aberrations obtained for near-infrared light, but intersubject variability limits accuracy for individual subjects.
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