period of visual immaturity

The period of visual immaturity is the stage of early life during which the retinocortical connections are not yet firmly established and can be modified by the quantity or quality of visual input. The same phase is called the sensitive, critical or susceptible period, and once the visual system matures, abnormal visual experience no longer changes its function.¹

The most critical period for loss of binocularity and for the development of amblyopia is the first 18 months of life. Plasticity then falls, quickly at first and then gradually, but the visual system remains sensitive to about 6 to 8 years of age, possibly to 10.² Different visual functions have different sensitive periods, and those for cortical functions last longer than those for retinal functions.^1,2

Amblyopia, suppression and anomalous retinal correspondence develop only in the immature visual system.³ The sensitive period for suppression appears to end after age 8 or 9 years, close to that for amblyopia, but suppression may persist throughout life once it develops. The capacity to develop anomalous retinal correspondence appears to extend into the early teens.³