Effect of pupil size on steady state accommodation

Ward, Patrick; Charman, W. N.

doi:10.1016/0042-6989(85)90047-1

Cited by 77 publications

(49 citation statements)

References 25 publications

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“…This increase in the subjective depth of focus and increased toleration of blur could contribute to the ability to cope with the decline in the accommodative response. Although pupil size was not measured in this study, the Canon R-1 autorefractor requires a pupil size greater than 2.9 mm, and thus the pupil size of the subjects used in this study is unlikely to have influenced the accommodative response [35].…”

Section: Depth Of Focusmentioning

confidence: 99%

The effect of incipient presbyopia on the correspondence between accommodation and vergence

Baker

Gilmartin

2002

Graefe's Arch Clin Exp Ophthalmol

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The results of this study fail to support the Hess-Gullstrand theory of presbyopia in that the ciliary muscle effort required to produce a unit change in accommodation increases, rather than stays constant, with age. Data show that the near vision response is limited to the maximum vergence response that can be tolerated and, despite being within the amplitude of accommodation, a stimulus may still appear blurred because the vergence component determines the proportion of available accommodation utilised during near vision.

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Section: Depth Of Focusmentioning

confidence: 99%

The effect of incipient presbyopia on the correspondence between accommodation and vergence

Baker

Gilmartin

2002

Graefe's Arch Clin Exp Ophthalmol

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“…Conversely, for distant objects the response exceeds the stimulus vergence and this error is often termed the accommodative 'lead'. Previous research has demonstrated that the accommodative response is dependent on subject and target characteristics such as pupil size [2,3], age [4] luminance [5] and spatial frequency [6,7]. In the absence of adequate visual stimuli accommodation adopts an intermediate resting position [8,9].…”

Section: Introductionmentioning

confidence: 99%

The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

Bullimore

Gilmartin

1988

Doc Ophthalmol

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The accommodative response of 12 emmetropic subjects was measured for an array of numbers located at -1, -3 and -5 dioptres using an objective infra-red optometer. Responses were compared for passive (reading numbers) and active (adding numbers) conditions. The imposition of mental effort induced a significant increase in mean response for the -1 D stimulus, a response equivalent to the passive condition at -3 D and a reduction in response at -5 D. Mental effort induced similar responses for the -1 D and -3 D locations when sympathetic innervation to the ciliary muscle was blocked with the beta-receptor antagonist timolol maleate. Responses for the -5 D location were, however, significantly increased. It is proposed that sympathetic inhibition can modify the effect of mental effort on near accommodative responses.

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“…The Bailey-Lovie chart employs a logarithmic progression of sizes and the IogMAR visual acuity notation, which has been shown to represent a good approximation to an equal discriminability scale (Westheimer, 1979) and has been recognized by many investigators as the most logical measure of visual acuity (Ogle, 1953;Working Group 39, 1980;Sloan, 1980;Frisen and Frisen, 198 1 ;Ferris et al, 1982;Horner, ef al., 1985;Strong and Woo, 1985). The Bailey-Lovie chart, or adaptations of it (Taylor, 1978;Ferris et al, 1982;Strong and Woo, 1985) has been used widely as a research tool for measuring and monitoring visual acuities in major projects such as the Early Treatment of Diabetic Retinopathy Study (Ferris et al, 1982), the Macular Photocoagulation Study (Macular Photocoagulation Study Group, 1982,1986, and the Prospective Evaluation of Radial Keratotomy study (Waring et al, 1983) and in many other smaller projects (Atchison, Smith and Efron, 1979;Carney, 1982;Ramsdale, 1985;Ross et al, 1985;Ward and Charman, 1985). For research purposes, Lovie-Kitchin and Bailey proposed an interpolated logMAR score (Lovie, 1976;Kitchin and Bailey, 198 1 ) to allow distinction between subjects with similar acuities.…”

Section: Bailey-lovie Chartmentioning

confidence: 99%

Validity and reliability of visual acuity measurements

Lovie‐Kitchin

1988

Ophthalmic Physiologic Optic

223

127

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A more scientific method than the Snellen chart for determining visual acuity is imperative for research studies and is desirable in many clinical situations. The psychometric method using the constant contour interaction S-chart of Flom has been regarded as an accurate and reliable visual acuity measure and has been used widely for research purposes. This paper compares visual acuity measured by the S-chart with that measured by the Snellen and Bailey-Lovie charts. The results indicate that the Baily-Lovie chart is a valid, reliable and rapid method of measuring threshold visual acuity for research purposes.

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Effect of pupil size on steady state accommodation

Cited by 77 publications

References 25 publications

The effect of incipient presbyopia on the correspondence between accommodation and vergence

The effect of incipient presbyopia on the correspondence between accommodation and vergence

The accommodative response, refractive error and mental effort: 1. The sympathetic nervous system

Validity and reliability of visual acuity measurements

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