title: The influence of stimulus size on measured visual field extent in infants.
abstract: OBJECTIVE
  To compare measured visual field extent for a 6 degrees stimulus (typical size used in studies of infants) with a 1.5 degrees stimulus (similar to the largest size used in Goldmann perimetry) in young infants.
  
  
  METHODS
  A total of 120 infants (60 each at 3.5 months and 7 months of age) and 24 adults were tested monocularly with a kinetic perimetry procedure using a black double-arc perimeter. Each subject was tested with either a 6 degrees or 1.5 degrees white sphere, which was mounted on a black wand and moved smoothly toward the intersection of the perimeter arms at 3.4 degrees /s. Visual field extent along each perimeter arm was defined as the median of 2 to 3 measurements of the position of the leading edge of the stimulus when the subject made an eye movement toward the stimulus.
  
  
  RESULTS
  The 6 degrees stimulus produced larger measured visual field extent than the 1.5 degrees stimulus in 3.5-month olds (temporal field only) and in 7-month olds (nasal and temporal field), but not in adults.
  
  
  CONCLUSIONS
  Using the testing conditions of the present study, increasing stimulus size beyond the largest used in a Goldmann perimeter (approximately 2 degrees) increases measured visual field extent in young infants, but not in adults. This may relate to differences in peripheral summation areas or to differences in attentional factors between infants and adults.
authors.affiliation: Department of Ophthalmology, University of Arizona, Tucson 85711, USA. udobson@eyes.arizona.edu
authors.forename: Velma
authors.initials: V
authors.lastname: Dobson
authors.forename: Meigan B
authors.initials: MB
authors.lastname: Baldwin
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Mohan
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Delaney
authors.forename: Erin M
authors.initials: EM
authors.lastname: Harvey
mesh_terms: D000328:Adult; D006801:Humans; D007223:Infant; D008875:Middle Aged; D015349:Vision, Monocular / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods*; D014794:Visual Fields / Q000502:physiology*