Early visual stimulation is critical to the normal development of the visual system. Early visual deprivation occurs when exposure to visual stimuli is limited in amount or intensity during initial stages of development. The outcome of early visual deprivation varies according to a variety of factors. Deprivation that is monocular and more severe and that occurs early in development generally leads to greater impairment. Length of deprivation also has an impact on the amount of impairment, and longer periods of deprivation lead to more detrimental outcomes (Boothe et al., 1985). Additionally, when the previous factors are present, the duration of deprivation needed to result in negative consequences is lessened.