title: Influence of eye rotation on peripheral eye length measurement obtained with a partial coherence interferometry instrument.
abstract: OBJECTIVE
  The eye rotation approach for measuring peripheral eye length leads to concern about whether the rotation influences results, such as through pressure exerted by eyelids or extra-ocular muscles. This study investigated whether this approach is valid.
  
  
  METHODS
  Peripheral eye lengths were measured with a Lenstar LS 900 biometer for eye rotation and no-eye rotation conditions (head rotation for horizontal meridian and instrument rotation for vertical meridian). Measurements were made for 23 healthy young adults along the horizontal visual field (± 30°) and, for a subset of eight participants along the vertical visual field (± 25°). To investigate the influence of the duration of eye rotation, for six participants measurements were made at 0, 60, 120, 180 and 210 s after eye rotation to ± 30° along horizontal and vertical visual fields.
  
  
  RESULTS
  Peripheral eye lengths were not significantly different for the conditions along the vertical meridian (F1,7 = 0.16, p = 0.71). The peripheral eye lengths for the conditions were significantly different along the horizontal meridian (F1,22 = 4.85, p = 0.04), although not at individual positions (p ≥ 0.10) and were not important. There were no apparent differences between the emmetropic and myopic groups. There was no significant change in eye length at any position after maintaining position for 210 s.
  
  
  CONCLUSIONS
  Eye rotation and no-eye rotation conditions were similar for measuring peripheral eye lengths along horizontal and vertical visual field meridians at ± 30° and ± 25°, respectively. Either condition can be used to estimate retinal shape from peripheral eye lengths.
authors: Visual and Ophthalmic Optics Laboratory, Institute of Health & Biomedical Innovation, School of Optometry & Vision Science, Queensland University of Technology, Brisbane, Australia.
authors: Pavan K
authors: PK
authors: Verkicharla
authors: Marwan
authors: M
authors: Suheimat
authors: Edward A H
authors: EA
authors: Mallen
authors: David A
authors: DA
authors: Atchison
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D058452:Axial Length, Eye / Q000033:anatomy & histology / Q000502:physiology*; D001699:Biometry / Q000295:instrumentation; D058453:Emmetropia / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D007368:Interferometry / Q000295:instrumentation / Q000379:methods*; D008297:Male; D009216:Myopia / Q000473:pathology*; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Lenstar; eye rotation; partial coherence interferometry; peripheral eye lengths; retinal shape