Clinical contrast sensitivity testing; the current status

Verbaken, J H; Johnston, Alan

doi:10.1111/j.1444-0938.1986.tb04593.x

Cited by 11 publications

(1 citation statement)

References 35 publications

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“…6 ). As for the second measurement, there are many clinical tests of contrast sensitivity, such as the Bailey-Lovie Low Contrast Acuity Chart 36 or Regan Charts, 37 which measure acuity for letters at a fixed low contrast; the Pelli-Robson Chart 14 or the MARS Chart, 15 which provide a contrast sensitivity measurement close to the peak of the CSF; and other contrast sensitivity tests such as the Melbourne Edge Test, 38 and the Berkeley Discs Contrast Sensitivity test (Bailey IL, et al IOVS 2011;52:E-Abstract 1892). The differences in acuity and a clinical contrast sensitivity measurement between a low-vision individual and the norms could then be used to shift a normal CSF horizontally along the log SF axis and vertically along the log CS axis.…”

Section: Discussionmentioning

confidence: 99%

Comparing the Shape of Contrast Sensitivity Functions for Normal and Low Vision

Chung

Legge

2016

Invest. Ophthalmol. Vis. Sci.

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PurposeThe contrast sensitivity function (CSF) provides a detailed description of an individual's spatial-pattern detection capability. We tested the hypothesis that the CSFs of people with low vision differ from a “normal” CSF only in their horizontal and vertical positions along the spatial frequency (SF) and contrast sensitivity (CS) axes.MethodsContrast sensitivity for detecting horizontal sinewave gratings was measured with a two temporal-interval forced-choice staircase procedure, for a range of SFs spanning 5 to 6 octaves, for 20 low-vision observers and five adults with normal vision. An asymmetric parabolic function was used to fit the aggregate data of the normal-vision observers, yielding the “normal template.” Each of the 20 low-vision CSFs was fit in two ways, by using a shape-invariant version of the normal template (with the width parameters fixed) that was shifted along the log-SF and log-CS axes, and by an unconstrained asymmetric parabolic function (“free-fit”).ResultsThe two fitting methods yielded values of the peak CS, the SF corresponding to peak CS, and the high cut-off SF that were highly correlated and in good agreement with each other. In addition, the width parameters of the low-vision CSFs were comparable with those of the normal template, implying that low-vision CSFs are similar in shape to the normal CSF.ConclusionsThe excellent agreement of parameters estimated by the two fitting methods suggests that low-vision CSFs can be approximated by a normal CSF shifted along the log-SF and log-CS axes to account for the impaired acuity and contrast sensitivity.

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