Visual processing is thought to involve initial local analyses that are 
subsequently integrated globally to derive functional representations of 
structure that extends over large areas of visual space. Amblyopia is a common 
deficit in spatial vision that could be based on either unreliable local 
estimates of image structure, irregularities in global image integration or a 
combination of errors at both these stages. The purpose of this study was to 
quantify the integration of local spatial information in amblyopia with global 
orientation discrimination and inter-ocular matching tasks. Stimuli were 
composed of pseudo-random arrays of highly visible and resolvable features 
(Gabor patches) whose local orientation and position were drawn from global 
distributions whose mean and variance statistics were systemically varied. 
Global orientation discrimination thresholds in both the amblyopic and fellow 
eye were elevated. The orientational and positional variances perceived by the 
amblyopic eye were matched by stimuli with higher variances perceived in the 
fellow eye. It would appear that amblyopes are able to integrate orientation 
information across visual space but the global representation of local structure 
shows greater variability compared to normal. It is this increased spatial 
uncertainty that underlies the spatial deficit in amblyopia.