Amblyopia: site unseen.

The site of the amblyopic deficit has been keenly sought for the past half century. Controversy has raged concerning whether it is retinal or cortical. Neurophysiologists and clinicians have provided compelling evidence to support their respective cases. Its resolution in terms of a primary cortical deficit is relatively recent and provides an interesting insight into the working of science. Currently, another controversy is beginning concerning which cortical areas are affected in amblyopia. Only time will tell if this new debate proves as interesting as its retinal counterpart. This review concentrates on where the site of the amblyopic deficit resides. It intentionally bypasses the issue of the nature of the deficit, an issue worthy of a separate review.