Modeling the contrast-sensitivity functions of older adults

Abstract

To determine whether a parabolic template is a good description of the contrast-sensitivity functions (CSF's) exhibited by older adults, the curve-fitting method of Pelli et al. [J. Opt. Soc. Am. A 3(13), P56 (1986)] was applied to contrast-sensitivity data from 100 older subjects (ages 53-85 years). Although the method resulted in reasonable fits for most subjects, closer inspection revealed that this technique may be problematic. A significant number of observers had functions that were nonparabolic, and for many subjects the error tended to be concentrated at the peak of the CSF. In addition, in contrast to the study of Pelli et al., the peak contrast sensitivities of the subjects were only weakly related to Pelli-Robson contrast sensitivity and letter acuity. The data were also fitted with an asymmetric function of variable shape. Whereas this function provided a better fit to the nonparabolic CSF's, it resulted in inferior fits to most of the remaining data. These results demonstrate that the spatial CSF's of older adults cannot be described by a single parametric curve such as a parabola or a function of an exponential and that Pelli-Robson contrast sensitivity and letter acuity are not adequate predictors of their peak contrast sensitivities.

A standard model for foveal detection of spatial contrast

“…This function is a parabola in a graph of log-sensitivity versus log-frequency (Ahumada & Peterson, 1992;Rohaly & Owsley, 1993). Including gain, it has four parameters.…”

“…Elsewhere, a curve that fits the average well has been found to be poor at fitting many individuals in a population of older observers (Rohaly & Owsley, 1993).…”

Multifocal intraocular lens technology: biomaterial, optical design and review of clinical outcomes

“…By 2005, the youthful, accommodating, emmetropic and minimally aberrated eye had become the standard by which the results of cataract and refractive surgery were evaluated. The erosion of accommodation and the decline in functional vision that occur with age [39] were both linked to changes in the crystalline lens [40,41]. Refractive cataract surgery therefore offered a natural avenue for the correction of presbyopia, as well as for the reversal of increasing lenticular SA.…”

Portable LCD Image Quality: Effects of Surround Luminance

“…The wealth of data in the literature also reports a variety of changes in CSF shape with senescence, (Owsley et al, 1983;Tulunay-Keesey et al, 1988;Higgins et al, 1988;Rohaly & Owsley, 1993;Pardhan, 2004) eccentricity (Rovamo et al, 1978;Koenderink et al, 1979;Wright & Johnston, 1983;Johnston, 1987;Snodderly et al, 1992) and degree of adaptation to noise (Farchild & Johnson, 2007) in a given stimulus. Briefly, luminance CSFs for older subjects exhibit losses in contrast sensitivity at the higher frequencies, although much of the loss is attributed to optical factors.…”