title: Eye motion increases temporal visual field extent.
abstract: OBJECTIVE
  To study the impact of eye motion on visual field extent.
  
  
  METHODS
  Visual fields were tested in 15 healthy volunteers with the Goldmann perimeter using a V4 test object, from seen to unseen, first in primary position of gaze, then allowing eye motion. Temporal points falling out of the cupola were tested again after a controlled nasal head rotation using a headband prototype fitted with a line-laser level having two orthogonal vial levels. Visual field surface areas (cm(2) ) were calculated as projections on a 30-cm virtual Goldmann cupola, whose extent would have been large enough to include all points. Reproducibility error of the method assessed by calculation of the relative difference between surface areas of 12 visual field tests and 12 visual field retests was estimated at 14%. Hertel exophthalmometry was recorded to study the influence of globe position on visual field extent.
  
  
  RESULTS
  Binocular visual field surface area increased by 37% with eye motion (p-value=1.20·10(-9) ). This increase was highest (46%; p-value=1.2·10(-24) ) in the temporal quadrant. Median maximal visual field temporal eccentricity with eye motion was 128.3° (minimum: 109.5°; maximum: 137.7°) and more than 135° in four eyes of three subjects. Hertel exophthalmometry was positively linked to visual field temporal surface area with eye motion (p-value=0.013).
  
  
  CONCLUSIONS
  Eye motion greatly expands the temporal visual field. This peculiarity is likely an adaptation to terrestrial life with upright bipedal locomotion and may save head movements through horizontal eyeball scanning.
authors.affiliation: Department of Ophthalmology, CHU de Caen, Caen, FranceDepartment of Biostatistics and Clinical Research, CHU de Caen, Caen, FranceMedical School, Université de Caen Basse-Normandie, Caen, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Denion
authors.forename: Audrey-E
authors.initials: AE
authors.lastname: Dugué
authors.forename: Sophie
authors.initials: S
authors.lastname: Coffin-Pichonnet
authors.forename: Sylvain
authors.initials: S
authors.lastname: Augy
authors.forename: Frédéric
authors.initials: F
authors.lastname: Mouriaux
mesh_terms: D000328:Adult; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D019416:Head Movements / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D008124:Locomotion / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015348:Vision, Binocular; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult
keywords: Hertel exophthalmometry; binocular visual field; driving; eye motion; eye movement; goldmann perimeter; quantification; visual field