title: Assessment of corneal curvature using verion optical imaging system: a comparative study.
abstract: BACKGROUND
  Keratometry is a critical determinant of the postoperative refractive outcome. This study evaluates the comparability of keratometry measurements obtained using the Verion Optical Imaging System with devices used in current clinical practice. Further, it determines the interobserver reliability of the Verion Optical Imaging System.
  
  
  METHODS
  Retrospective analysis of patient data
  
  
  METHODS
  Keratometric data was obtained from 100 patients presenting for pre-operative evaluation. Furthermore, repeatability and reproducibility were assessed using 15 healthy volunteers.
  
  
  METHODS
  Corneal curvature values acquired by the Verion Optical Imaging System were compared with existing keratometry devices including autokeratometry, partial coherence interferometry (IOLMaster) and Scheimpflug corneal topography (Pentacam).
  
  
  METHODS
  Direct comparison of corneal power, cylinder, axis of astigmatism and vector analysis were performed using correlation and Bland-Altman analyses. Reproducibility and reliability of the device were assessed using within-subject standard deviation and intraclass correlation coefficients for experienced and inexperienced technicians.
  
  
  RESULTS
  There was no statistically significant difference between Verion values and those obtained by other methods in relation to mean keratometry, corneal astigmatism, steep meridian and vector analyses (P > 0.05). Bland-Altman plots showed narrow limits of agreement for keratometry and astigmatism and wider agreement for steep meridian. Intraoperator reliability for both experienced and inexperienced operators and interoperator reproducibility showed no statistically significant differences between values.
  
  
  CONCLUSIONS
  Measurements show no significant difference from those obtained by the other devices. This suggests the Verion system is en par with instruments used in current clinical practice. The Verion Optical Imaging System produces repeatable data with no difference related to operator experience.
authors.affiliation: Vision Eye Institute Chatswood, Sydney, New South Wales, Australia.|Department of Ophthalmology, Prince of Wales Hospital, Sydney, New South Wales, Australia.
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Lauschke
authors.affiliation: Vision Eye Institute Chatswood, Sydney, New South Wales, Australia.|Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Lawless
authors.affiliation: Vision Eye Institute Chatswood, Sydney, New South Wales, Australia.|Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Gerard
authors.initials: G
authors.lastname: Sutton
authors.affiliation: Vision Eye Institute Chatswood, Sydney, New South Wales, Australia.|Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Roberts
authors.affiliation: Vision Eye Institute Chatswood, Sydney, New South Wales, Australia.
authors.forename: Christopher
authors.identifier: http://orcid.org/0000-0002-0516-6486
authors.initials: C
authors.lastname: Hodge
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001251:Astigmatism / Q000175:diagnosis*; D002387:Cataract Extraction; D003315:Cornea / Q000473:pathology*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D019654:Lens Implantation, Intraocular; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D061848:Optical Imaging / Q000295:instrumentation*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
keywords: corneal curvature; iolmaster; keratometry; pentacam; topcon; verion optical imaging