Fluctuations in accommodation: a review

Charman, W. N.; Heron, Gordon

doi:10.1111/j.1475-1313.1988.tb01031.x

Cited by 246 publications

(203 citation statements)

References 57 publications

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“…The spectral estimator of an AR process of order is given by (6) where and are the least-square estimators of and , respectively. In Fig.…”

Section: B Frequency Domain Representationmentioning

confidence: 99%

“…The results of these studies have consistently shown that during steady viewing conditions the eye constantly changes its focus (accommodation). The magnitude of these changes in accommodation are typically less than D (Diopter) and have a maximal amplitude of about 0.5 D [6]. The temporal frequencies of the accommodation fluctuations are typically less than 2 Hz.…”

Section: Introductionmentioning

confidence: 99%

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Analyzing the Dynamic Wavefront Aberrations in the Human Eye

Iskander

Collins

Morelande

et al. 2004

IEEE Trans. Biomed. Eng.

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Abstract-The optics of the human eye are not static in steady viewing conditions and exhibit microfluctuations. Previous methods used for analyzing dynamic changes in the eye's optics include simple Fourier-transform-based methods, which have been used in studies of the eye's accommodation response. However, dedicated tools for the analysis of dynamic wavefront aberrations have not been reported. We propose a set of signal processing tools, the combination of which uncovers aspects of the dynamics of eye's optical aberrations which were hidden from conventional analysis techniques. The methodology includes extraction of artifacts from potentially significant eye movements, filtering, optimal parametric signal modeling, and frequency and time-frequency representations. The exposition of the techniques and their advantages over traditional techniques is illustrated for real dynamic eye wavefront aberration measurements.

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“…The spectral estimator of an AR process of order is given by (6) where and are the least-square estimators of and , respectively. In Fig.…”

Section: B Frequency Domain Representationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analyzing the Dynamic Wavefront Aberrations in the Human Eye

Iskander

Collins

Morelande

et al. 2004

IEEE Trans. Biomed. Eng.

View full text Add to dashboard Cite

show abstract

“…Despite this, the continuous microfluctuations of the accommodative response occur naturally over approximately a 0.25 D to 0.50 D range, producing a potential variation of up to 0.50 D between readings. 10 Microfluctuations are potentially more of a problem in autorefractor measurements, as refraction is measured in a very short period, although some allowance for this can be made by averaging a number of measurements. Another problem associated with accommodation is that some individuals exhibit an increase in the accommodation response when viewing an autorefractor target.…”

mentioning

confidence: 99%

Clinical evaluation of patient tolerance to autorefractor prescriptions

Strang

Gray

Winn

et al. 1998

Clinical and Experimental Optometry

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Background:In clinical optometric practice, autorefractors are used as an objective measure of refractive error prior to subjective refraction. We evaluate the clinical efficacy of autorefractor measurements by determining whether spectacles can be prescribed from autorefractor results. Methods: Forty-seven subjects were randomly allocated spectacles using prescriptions determined either by an optometrist or from an autorefractor in a double-blind protocol. Subjects wore each prescription for two weeks and completed an oral questionnaire following each period of wear. The questionnaire assessed both pairs of spectacle lenses in terms of visual performance and ocular comfort. Results: The level of negative responses to all questions was higher for spectacles based on the autorefractor findings than for those based on the optometrist's prescriptions. Having reported initial discomfort, many subjects indicated that they had adapted to the spectacle lenses over a two-week period. Conclusions: Our results suggest that, in a clinical environment, subjective refraction produces a more accurate and acceptable spectacle prescription than an autorefractor.

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“…Thus, the results shown here provide new insights into an eye disorder as common as presbyopia (32,33) .…”

Section: Discussionmentioning

confidence: 93%

Análise da capacidade de acomodação em pacientes présbitas com baixo índice de massa corporal

Damasceno¹,

Damasceno

2013

Rev. bras.oftalmol.

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Purpuse: To determine the correlation between presbyopia and body mass index. Methods: Cross-sectional study involving 1030 patients with visual acuity of 20/20 emmetropy, aged between 36-40 years, 51-55 years and 60-65 years, excluding patients with positive test cover, anisometropy with convergence insufficiency or high correlation convergence / accommodation. Assessment of body mass index of all patients, Results: Cross-sectional study involving 1030 patients with visual acuity of 20/20 emmetropy, aged between 36-40 years, 51-55 years and 60-65 years, excluding patients with positive cover test, anisometropy with convergence insufficiency or high correlation convergence / accommodation. Assessment of body mass index of all patients Conclusion: As demonstrated by statistical analysis there is a significant correlation between low body weight defined as a body mass index below 18.5 and a lower incidence of presbyopia or delay its onset and progression with age.Keywords: Presbyopia; Low body weight; Body mass index RESUMO Dobras de coroide é considerado o achado fundoscópico mais prevalente nos casos de tumor orbitário. São ondulações no epitélio pigmentado da retina, membrana de Bruch, porção interna da coriocapilar e que, em alguns casos, podem acometer a retina neurossensorial, sendo então chamadas de dobras coriorretinianas. Diversas condições, oculares e sistêmicas, cursam com dobras de coroide e devem ser corretamente investigadas e, caso necessário, prontamente tratadas. Nesta revisão iremos abordar os aspectos gerais das dobras de coroide, enfatizando suas características nos seguintes exames de imagem: Retinografia, autofluorescência, angiofluoresceínografia e tomografia de coerência óptica.

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Fluctuations in accommodation: a review

Cited by 246 publications

References 57 publications

Analyzing the Dynamic Wavefront Aberrations in the Human Eye

Analyzing the Dynamic Wavefront Aberrations in the Human Eye

Clinical evaluation of patient tolerance to autorefractor prescriptions

Análise da capacidade de acomodação em pacientes présbitas com baixo índice de massa corporal

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