title: Maximum angle of ocular duction during visual fixation as a function of age.
abstract: OBJECTIVE
  To measure and compare the maximum angle of ocular duction in healthy individuals as a function of age.
  
  
  METHODS
  A calibrated arc perimeter was modified to display one of six randomly presented targets (high contrast Snellen equivalent letters), in both vertical (supra/infraduction) and horizontal (ab/adduction) gaze to the dominant eye of 204 healthy volunteers with best-corrected visual acuity. A bite-bar and headrest were employed to prevent head movement. Using a modified method of limits for discrimination threshold, a maximum mean angle of ocular duction was determined by stepping a target out in 5 degrees steps until an error was reported and thereafter bracketing around the limits of the target identification in 1 degrees steps. A mean threshold value was determined as the angle at which a subject obtained a correct response 75% of the time in two and as many as the trails in each of the four randomly presented directions of gaze (abduction, adduction, supraduction and infraduction).
  
  
  RESULTS
  A decrease in mean maximum duction angle was found over all age groups in al four directions (p < 0.001), with a step decline beginning in the sixth decade and almost doubling in the oldest age group tested (80-95 years-olds). The percent change in mean maximum angle of duction due to age from the 14-19 to the 80-95 year-olds was: abduction 21%, adduction 24%, supraduction 35%, infraduction 26%.
  
  
  CONCLUSIONS
  Baseline data are useful to differentiate normal changes occurring with age from early signs of disease. AdditIonally, disease progression and effects of treatment can be monitored.
authors.affiliation: The College of Optometry, Nova Southeastern University, Fort Lauderdale, FL 33328, USA.
authors.forename: Diana
authors.initials: D
authors.lastname: Shechtman
authors.forename: Josephine
authors.initials: J
authors.lastname: Shallo-Hoffmann
authors.forename: Jay
authors.initials: J
authors.lastname: Rumsey
authors.forename: Paul
authors.initials: P
authors.lastname: Riordan-Eva
authors.forename: Patrick
authors.initials: P
authors.lastname: Hardigan
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003941:Diagnostic Techniques, Ophthalmological; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000502:physiology; D014792:Visual Acuity