title: The contrast sensitivity of the newborn human infant.
abstract: OBJECTIVE
  To measure the binocular contrast sensitivity (CS) of newborn infants using a fixation-and-following card procedure.
  
  
  METHODS
  The CS of 119 healthy newborn infants was measured using stimuli printed on cards under the descending method of limits (93 infants) and randomized/masked designs (26 infants). One experienced and one novice adult observer tested the infants using vertical square-wave gratings (0.06 and 0.10 cyc/deg; 20/10,000 and 20/6000 nominal Snellen equivalent); the experienced observer also tested using horizontal gratings (0.10 cyc/deg) and using the Method of Constant Stimuli while being kept unaware of the stimulus values.
  
  
  RESULTS
  The CS of the newborn infant was 2.0 (contrast threshold = 0.497; 95% confidence interval: 0.475-0.524) for vertically oriented gratings and 1.74 (threshold = 0.575; 95% confidence interval: 0.523-0.633) for horizontally oriented gratings (P < 0.0006). The standard deviation of infant CS was comparable to that obtained by others on adults using the Pelli-Robson chart. The two observers showed similar practice effects. Randomization of stimulus order and masking of the adult observer had no effect on CS.
  
  
  CONCLUSIONS
  The CS of individual newborn human infants can be measured using a fixation-and-following card procedure.
authors.affiliation: College of Optometry, The Ohio State University, Columbus, Ohio, United States.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Brown
authors.affiliation: College of Optometry, The Ohio State University, Columbus, Ohio, United States Department of Psychology, The Ohio State University, Mansfield, Columbus, Ohio, United States.
authors.forename: Delwin T
authors.initials: DT
authors.lastname: Lindsey
authors.affiliation: College of Optometry, The Ohio State University, Columbus, Ohio, United States.
authors.forename: Joanna G
authors.initials: JG
authors.lastname: Cammenga
authors.affiliation: College of Medicine, The Ohio State University, Columbus, Ohio, United States Kentucky Children's Hospital, University of Kentucky College of Medicine, Lexington, Kentucky, United States.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Giannone
authors.affiliation: College of Medicine, The Ohio State University, Columbus, Ohio, United States Nationwide Children's Hospital, Columbus, Ohio, United States.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Stenger
mesh_terms: D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D012684:Sensory Thresholds; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology
keywords: card procedure; contrast sensitivity; fixation-and-following; neonatal; newborn