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Xin Jie Lai, Suzanne McKee, Chuan Hou, Preeti Verghese; Cueing Attention Takes More Time in Strabismic Amblyopes. Journal of Vision 2013;13(9):470. doi: 10.1167/13.9.470.
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© ARVO (1962-2015); The Authors (2016-present)
Previous studies have shown that amblyopic observers, like normal observers, can use visual cues to enhance contrast detection of peripheral targets (Sharma et al, 2000; Kiorpes et al., 2012). However, attentional processes in amblyopes appear to differ from normal (Popple & Levi, 2008; Farzin & Norcia, 2011). We speculated that strabismic amblyopic observers might take longer to use cues, meaning that the asynchrony between cue and test target that produced enhanced contrast detection would be delayed relative to normal observers. To test this idea, we measured the timing of central and peripheral cues in normal and amblyopic observers. Observers were asked to judge the orientation (horizontal or vertical) of a threshold Gabor patch (2cpd, 60 msec duration) presented at 7 degrees eccentricity in one of four quadrants, chosen at random. The onset asynchrony between cue and test patch was varied randomly from trial to trial. The peripheral cue was a large square that framed the target location; the central cue was a short line presented near fixation that pointed to the quadrant where the target would appear. Observers viewed stimuli in a stereoscope, where targets were presented monocularly to only one eye, or binocularly at random to either the right or left eye. For both normal and amblyopic observers, the asynchrony that produced enhanced detection was shorter for peripheral than for central cues, consistent with previous findings (Nakayama & MacKeben 1989; Cheal & Lyon, 1991). However, for amblyopes, cue enhancement was delayed compared to normal for both types of cues. While there was no difference between monocular and binocular conditions for normal observers, the added burden of monitoring both eyes simultaneously in the binocular condition further delayed cueing in these stereo-blind strabismics. The ability to direct attention quickly to targets of interest is impaired in strabismic amblyopia.
Meeting abstract presented at VSS 2013
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