There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.
Abstract
There have now been numerous reports of a spatial localization deficit in amblyopia
but none so far have tackled (1) the relationship between the contrast sensitivity
and spatial localization deficits and (2) whether the spatial localization deficit
is best described in units of visual angle or in terms of the underlying filter size.
These issues are germane because they lie at the very heart of our understanding of
the underlying deficit in amblyopia. To answer these questions we use spatially bandpass
stimuli so that we can readily compare detection and localization for the same stimuli
at each of a number of spatial scales. For some amblyopes (all strabismics and a minority
of anisometropes) the contrast sensitivity defect neither underlies nor covaries with
the spatial localization deficit. In the majority of anisometropic amblyopes, the
contrast sensitivity loss is a complete description. The spatial localization deficit
in amblyopia is of two independent kinds; positional inaccuracy and positional distortion.
The positional inaccuracy deficit which can occur in varying degrees in both strabismic
and anisometropic amblyopia, affects all spatial scales equally and therefore is best
thought of in terms of a constant fraction of the underlying filter size in the space-frequency
plane. The positional distortion deficit which can also occur to varying degrees in
both strabismic and anisometropic forms can not be easily understood within this metric
at least for strabismics.