Effects Of High Frequency Filtering On Visual Search In Reading Disabled Children.

Recent experimental evidence has described the existence of two parallel visual subsystems which operate from the retina to the visual cortex, the sustained system and the transient system. The primary function of the sustained system is to transmit detailed information about the visual stimulus. It functions predominantly as a pattern detection system. The sustained system is most sensitive to stationary stimuli. It is a high acuity, high spatial and low temporal frequency system. It responds throughout the stimulus presentation and continues its activity after removal of the stimulus, producing a significant persistence effect, thus the name sustained system. The sustained system is most important in visual acuity and color vision. The sustained system seems to be best designed for the identification of patterns, resolution of fine detail and the perception of color.