The effect of defocus on edge contrast sensitivity

Jansonius, N. M.; Kooijman, A. C.

doi:10.1046/j.1475-1313.1997.96000543.x

Cited by 8 publications

(18 citation statements)

References 10 publications

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“…12 cpd, and for detecting edges, i.e. 3 cpd (King‐Smith and Kulikowski, 1972; Jansonius and Kooijman, 1997). Because the measured dioptric range was limited on the negative side, the depth of focus was defined as twice the positive half of the dioptric range in which the contrast sensitivity exceeded half its maximum value.…”

Section: Methodsmentioning

confidence: 53%

“…Therefore, their data with a 3‐mm pupil are in agreement with ours. Jansonius and Kooijman (1997) took measurements in six subjects not administered cycloplegic drugs. The natural pupil size of their population varied between 4.5 and 7 mm.…”

Section: Discussionmentioning

confidence: 99%

“…Contrast threshold measurements under defocusing circumstances have been reported by Campbell and Green (1965), Green and Campbell (1965), Charman (1979), Kay and Morrison (1987), Jansonius and Kooijman (1997), and Nio et al . (2000) and show the attenuating effect of defocus on contrast sensitivity.…”

Section: Introductionmentioning

confidence: 99%

“…(1987) performed their measurements on large pupils and negative values of defocus, they only used two subjects. Other through‐focus measurement studies included similar small numbers of subjects and only positive defocus values (Campbell and Green, 1965; Jansonius and Kooijman, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…The RMT data in the present study agree with those found in other studies, e.g. Campbell and Green (1965) and Jansonius and Kooijman (1997). A new theoretical eye model using a spherical aberration intermediate between those of the eye models described by Jansonius and Kooijman (1998) and an irregular aberration with a typical S.D.…”

mentioning

confidence: 99%

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Spherical and irregular aberrations are important for the optimal performance of the human eye

Nio

Jansonius

Fidler

et al. 2002

Ophthalmic Physiologic Optic

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Contrast sensitivity measured psychophysically at different levels of defocus can be used to evaluate the eye optics. Possible parameters of spherical and irregular aberrations, e.g. relative modulation transfer (RMT), myopic shift, and depth of focus, can be determined from these measurements. The present paper compares measured results of RMT, myopic shift, and depth of focus with the theoretical results found in the two eye models described by Jansonius and Kooijman (1998). The RMT data in the present study agree with those found in other studies, e.g. Campbell and Green (1965) and Jansonius and Kooijman (1997). A new theoretical eye model using a spherical aberration intermediate between those of the eye models described by Jansonius and Kooijman (1998) and an irregular aberration with a typical S.D. of 0.3-0.5 D could adequately explain the measured RMT, myopic shift, and depth of focus data. Both spherical and irregular aberrations increased the depth of focus, but decreased the modulation transfer (MT) at high spatial frequencies at optimum focus. These aberrations, therefore, play an important role in the balance between acuity and depth of focus.

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Section: Methodsmentioning

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Spherical and irregular aberrations are important for the optimal performance of the human eye

Nio

Jansonius

Fidler

et al. 2002

Ophthalmic Physiologic Optic

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Decoding PERG: a Neuro-Ophthalmic Retinal Ganglion Cell Function Review

Monsalve

2019

Curr Ophthalmol Rep

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Purpose of review: Currently, the clinical evaluation of neuro-ophthalmologic diseases are mainly focused on identifying stages where structural or functional damage occur. Recognition of retinal ganglion cell (RGC) functional patterns as well as monitoring RGC dysfunction can be performed using steady-state pattern electroretinogram (PERG). The analysis of the amplitude and latency shift aid on providing information on early damage or monitoring of the RGC, allowing for prompt clinical intervention and management modification, potentially changing the natural history of the disease. The purpose of this article is to review the latest findings in PERG, in early manifest glaucoma, non arteritic ischemic optic neuropathy, multiple sclerosis with unilateral recovered optic neuritis and its fellow eyes. Recent Findings:The steady-state PERG responses provide new and early specific information in neuro-ophthalmic diseases affecting the inner retina.Summary: Steady state PERG presents specific amplitude and latency outcomes based on the neuro-ophthalmic disease affecting the inner retina, allowing early recognition of changes at the level of RGC and the degree of RGC dysfunction. In addition, PERG alterations may be induced in healthy subjects as well as susceptible eyes using different stress tests such as head down tilting or water drinking tests.

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Age‐related changes of defocus‐specific contrast sensitivity in healthy subjects

Nio

Jansonius

Fidler

et al. 2000

Ophthalmic Physiologic Optic

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To investigate the effect of defocus on contrast sensitivity as a function of age in healthy subjects, the through focus contrast sensitivity was measured in 100 healthy subjects aged 20-69. Defocus-specific changes in contrast sensitivity reflect age-related changes in the optics of the eye. Tests were performed in cycloplegic eyes varying artificial pupil size (2, 4 and 6 mm), defocus (-1 to +2 D), and spatial frequency (1-16 cpd). Integrated contrast sensitivity was taken as a measure for the total amount of visual information transferred by the optical media. At optimal focus, integrated contrast sensitivity and log contrast sensitivity at 8 cpd showed a significant age-related decline. The log contrast sensitivity at 1 cpd appeared to be independent of age. The depth of focus for a 4-mm pupil increased significantly with age, even though contrast sensitivity at +2 D defocus decreases with age too, but not as much as the contrast sensitivity at optimal focus. Our study indicates that the effect of defocus on contrast sensitivity decreases with age; this was attributed to age-related changes in the optical media.

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The effect of defocus on edge contrast sensitivity

Cited by 8 publications

References 10 publications

Spherical and irregular aberrations are important for the optimal performance of the human eye

Spherical and irregular aberrations are important for the optimal performance of the human eye

Decoding PERG: a Neuro-Ophthalmic Retinal Ganglion Cell Function Review

Age‐related changes of defocus‐specific contrast sensitivity in healthy subjects

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