Restoration of underdeveloped cortical functions: evidence from treatment of adult amblyopia.

Amblyopia is a reduction of visual functions that cannot be attributed directly to the effect of any structural abnormality of the eye or the posterior visual pathway. It is caused by abnormal binocular visual experience early in life, during the 'critical period' that prevents normal development of the visual system. It is widely accepted that therapy can only be effective during the critical period, and that it is not administered after the first decade of life. Here we provide an overview describing a recent finding of visual abnormalities in amblyopia and propose a treatment that we developed based on this finding. Both previous and new results that are presented here clearly show the success of the structured method, targeted at the specific deficiencies in amblyopia, to improve vision in children and adults. Our results suggest that the training was successful in rejuvenating the visual system and in restoring lost development from the sensory obstacle period. It is possible that the perceptual learning method used here can be applied to other sensory and non-sensory brain modules suffering from developmental problems.