The neural deficit in strabismic amblyopia: sampling considerations

In order to understand the nature of the neural loss in strabismic amblyopia, we have applied a technique which has been used in the normal periphery to psychophysically probe the sampling properties of the neuronal population. We ask whether there is a 'sampling' deficit and if so whether it is based on either an absolute loss of neurons (i.e. spatial undersampling) or an irregular arrangement of a normal number of neurons (i.e. irregular sampling). Our results suggest that neural pooling restricts the spatial frequency region where sampling considerations are important to a very small part of the visible high spatial frequency range. Within this limited region, irregular sampling rather than spatial undersampling is the greater contributor to the strabismic amblyope deficit.