title: Refraction and aberration across the horizontal central 10 degrees of the visual field.
abstract: OBJECTIVE
  The purpose of this study was to measure refraction and aberrations across the horizontal central visual field.
  
  
  METHODS
  Cycloplegic refraction was measured on eight subjects at 13 points across the horizontal central 10 degrees of the retina using a Hartmann-Shack wavefront sensor. Refractions were converted into mean sphere (M), 90 degrees to 180 degrees astigmatism (J180), and 45 degrees to 135 degrees astigmatism (J45) components. For five subjects, higher-order aberrations were determined at the center and edges of the field.
  
  
  RESULTS
  Subtle changes in refraction were found to exist across the central 10 degrees of the retina, with changes in mean best sphere varying by up to half a diopter across this region and with smaller changes in astigmatism. Horizontal coma, but no other higher-order aberrations, varied systemically across the visual field; it varied linearly with angle but at different rates for the different subjects.
  
  
  CONCLUSIONS
  Subtle changes in cycloplegic refraction exist across the horizontal central 10 degrees of the retina. The results indicate the need for correct alignment when measuring objective refraction.
authors.affiliation: Ophthalmic and Visual Optics Group, School of Optometry, Queensland University of Technology, Australia. d.atchison@qut.edu.au
authors.forename: David A
authors.initials: DA
authors.lastname: Atchison
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Lucas
authors.forename: Ross
authors.initials: R
authors.lastname: Ashman
authors.forename: Michael A
authors.initials: MA
authors.lastname: Huynh
authors.forename: David W
authors.initials: DW
authors.lastname: Schilt
authors.forename: Phuc Q
authors.initials: PQ
authors.lastname: Ngo
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012029:Refraction, Ocular / Q000502:physiology*; D012720:Severity of Illness Index; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*