Foveal contour interaction for low contrast acuity targets

Siderov, John and Waugh, Sarah J. and Bedell, Harold E. (2013) Foveal contour interaction for low contrast acuity targets. Vision Research, 77. pp. 10-13. ISSN 1878-5646

Accepted Version
Available under the following license: Creative Commons Attribution Non-commercial No Derivatives.

Download (111kB) | Preview
Official URL:


Previous investigators reported the impairment of foveal visual acuity by nearby flanking targets (contour interaction) is reduced or eliminated when acuity is measured using low contrast targets. Unlike earlier studies, we compared contour interaction for high and low contrast acuity targets using flankers at fixed angular separations, rather than at specific multiples of the acuity target’s stroke width. Percent correct letter identification was determined in 4 adult observers for computer generated, high and low contrast dark Sloan letters surrounded by 4 equal contrast flanking bars. Two low contrast targets were selected to reduce each observer’s visual acuity by 0.2 and 0.4 logMAR. The crowding functions measured for high and low contrast letters are very similar when percent correct letter identification is plotted against the flanker separation in min arc. These results indicate that contour interaction of foveal acuity targets occurs within a fixed angular zone of a few min arc, regardless of the size or contrast of the acuity target.

Item Type: Journal Article
Keywords: Contour interaction, Crowding, Contrast, Acuity, Sloan letter
Faculty: ARCHIVED Faculty of Science & Technology (until September 2018)
Depositing User: Repository Admin
Date Deposited: 16 Dec 2013 12:13
Last Modified: 09 Sep 2021 19:02

Actions (login required)

Edit Item Edit Item