The effect of visual loss affects the development of the visual cortex of the brain—the visual impairment causes the occipital lobe to lose its sensitivity in perceiving spatial processing. Siu and Morley (2008) proposed that following seven days of visual deprivation, a potential decrease in vision may occur. They also found an increasing degree of visual impairment following thirty-day and 120-day periods of deprivation. The Siu and Morley study suggests that the function of the brain is dependent upon visual input.