“…The fact that posttraining residual impairments involved deficits in contrast sensitivity as well as fine discrimination abilities suggest that they could arise from low signal-to-noise ratio and/or a general deficit in suppressing irrelevant signals at retrained blind field locations. Indeed, perceptual deficits have been shown to result solely or jointly from a failure to differentiate signal from both external and internal noise as well as from low information sampling efficiency (Pelli, 1981;Legge, Kersten, & Burgess, 1987;Pelli & Farell, 1999;Simpson, Falkenberg, & Manahilov, 2003;Dakin, Mareschal, & Bex, 2005;Lu, Chu, Dosher, & Lee, 2005;Lu, Chu, & Dosher, 2006;Lu & Dosher, 2008). Visual deficits in normal aging (Bennett, Sekuler, & Ozin, 1999;Bower & Anderson, 2012), following visual cortex damage (Hayes & Merigan, 2006), and in amblyopia (Pelli, Levi, & Chung, 2004;Xu, Lu, Qiu, & Zhou, 2006;Huang, Lu, & Zhou, 2009) are all associated with at least one of these processing limitations.…”