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Estimating the critical duration for temporal summation of standard achromatic perimetric stimuli

Mulholland, Padraig J., Redmond, Tony, Garway-Heath, David F., Zlatkova, Margarita B. and Anderson, Roger S. 2015. Estimating the critical duration for temporal summation of standard achromatic perimetric stimuli. Investigative Ophthalmology and Visual Science 56 (1) , pp. 431-437. 10.1167/iovs.14-15304

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Abstract

Purpose: To estimate the critical duration of temporal summation for achromatic Goldmann III stimuli under the conditions of standard automated perimetry (SAP) and quantify response variability for short duration stimuli. Methods: Contrast thresholds were gathered using the method of constant stimuli for seven circular (0.48° diameter) incremental stimuli of varying duration (sum-of-frames equivalent: 8.3-198.3 msec), at an eccentricity of 8.8° along the four principal meridians of the visual field in two healthy, psychophysically experienced observers. Stimuli were presented on a high-resolution CRT display with a background luminance of 10 cd/m2. Psychometric functions were fitted using a probit model and non-parametric local linear analysis. The critical duration was estimated using iterative two-phase regression analysis, the results also being compared with values produced using previously published methods of analysis. Results: The median critical duration estimated using iterative two-phase regression analysis was 27.7 msec (IQR 22.5-29.8). A slight steepening of the psychometric function slope (lower variability) was observed for longer stimulus durations, using both probit and local-linear analysis techniques, but this was not statistically significant. Conclusions: Critical duration estimates in this study are substantially shorter than those previously reported for a Goldmann III stimulus under the conditions of SAP. Further work is required to firmly establish the relationship between measurement variability and the degree of local temporal and spatial summation.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Optometry and Vision Sciences
Subjects: R Medicine > RE Ophthalmology
Additional Information: Published online: 16/12/14.
Publisher: Association for Research in Vision and Ophthalmology
ISSN: 0146-0404
Date of First Compliant Deposit: 22 September 2016
Date of Acceptance: 3 December 2014
Last Modified: 16 Sep 2019 08:59
URI: http://orca.cf.ac.uk/id/eprint/68467

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