Practice makes perfect:Crowdingtraining improves visual functions in children with visual impairment

Abstract

Crowding is a visual perceptual phenomenon that refers to impaired ability to recognize a suprathreshold object when it is presented in the vicinity of other objects. Crowding therefore poses a limit on object recognition. The phenomenon is regarded to be one of the reasons why young children need large textbook letters. Several studies have provided evidence that crowding imposes a bottleneck on reading speed, and reading long words. Thus, crowding influences visual perception and object recognition in young children. Recent studies show that crowding is stronger in children with visual impairment than in children with normal vision. But which factors are responsible for these strong crowding effects? And how can we reduce crowding in children with visual impairment for whom low visual acuity in itself already poses a bottleneck on object recognition? This review article tries to answer these questions. This knowledge is useful for educational psychologists, because crowding can interfere with the acquisition of academic skills and reading. Keywords: crowding, learning, visual impairment, visual acuity, visual attention.<br/