CRITICAL PERIODS AND AMBLYOPIA

During the past 20 years, basic science has shown that there are diffe rent critical periods for different visual functions during the develo pment of the visual system. Visual functions processed at higher anato mical levels within the system have a later critical period than funct ions processed at lower levels. This general principle suggests that t reatments for amblyopia should be followed in a logical sequence, with treatment for each visual function to be started before its critical period is over. However, critical periods for some visual functions, s uch as stereopsis, are not yet fully determined, and the optimal treat ment is, therefore, unknown. This article summarizes the current exten t of our knowledge and points to the gaps that need to be filled.