title: Peripheral vision of youths with low vision: motion perception, crowding, and visual search.
abstract: OBJECTIVE
  Effects of low vision on peripheral visual function are poorly understood, especially in children whose visual skills are still developing. The aim of this study was to measure both central and peripheral visual functions in youths with typical and low vision. Of specific interest was the extent to which measures of foveal function predict performance of peripheral tasks.
  
  
  METHODS
  We assessed central and peripheral visual functions in youths with typical vision (n = 7, ages 10-17) and low vision (n = 24, ages 9-18). Experimental measures used both static and moving stimuli and included visual crowding, visual search, motion acuity, motion direction discrimination, and multitarget motion comparison.
  
  
  RESULTS
  In most tasks, visual function was impaired in youths with low vision. Substantial differences, however, were found both between participant groups and, importantly, across different tasks within participant groups. Foveal visual acuity was a modest predictor of peripheral form vision and motion sensitivity in either the central or peripheral field. Despite exhibiting normal motion discriminations in fovea, motion sensitivity of youths with low vision deteriorated in the periphery. This contrasted with typically sighted participants, who showed improved motion sensitivity with increasing eccentricity. Visual search was greatly impaired in youths with low vision.
  
  
  CONCLUSIONS
  Our results reveal a complex pattern of visual deficits in peripheral vision and indicate a significant role of attentional mechanisms in observed impairments. These deficits were not adequately captured by measures of foveal function, arguing for the importance of independently assessing peripheral visual function.
authors: Center for Visual Science, Department of Brain and Cognitive Sciences, University of Rochester, Rochester, New York 14627, USA. duje@cvs.rochester.edu
authors: Duje
authors: D
authors: Tadin
authors: Jeffrey B
authors: JB
authors: Nyquist
authors: Kelly E
authors: KE
authors: Lusk
authors: Anne L
authors: AL
authors: Corn
authors: Joseph S
authors: JS
authors: Lappin
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D009039:Motion Perception / Q000502:physiology*; D010468:Perceptual Disorders / Q000503:physiopathology*; D014787:Vision Tests; D015354:Vision, Low / Q000503:physiopathology*; D014785:Vision, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*