title: Is intraoperative topography predictive of postoperative topographical changes following refractive surgery?
abstract: OBJECTIVE
  To evaluate the usefulness of measuring corneal topography intraoperatively by Intraoperative PAR Corneal Topography System (IOPAR CTS) to predict the postoperative topographical changes in patients undergoing refractive surgery.
  
  
  METHODS
  Topographical measurements of 9 eyes of 9 patients were taken by IOPAR CTS: 6 immediately after Intrastromal Corneal Ring Segments (ICRS) placement surgery and 3 immediately after Photorefractive Keratectomy (PRK) surgery. The topographical images taken by IOPAR CTS were analyzed to determine the quality of the image produced and the correlation of the keratometric data from the central 3 mm of cornea with measurements taken from an autokeratometer (Auto-Km) and the EyeSys Corneal Analysis System (CAS) for the same eyes taken three months following the procedure.
  
  
  RESULTS
  At the 3-month postoperative exam, the correlation coefficients for flat (K1), steep (K2), and average keratometry (AK) readings produced by the Auto-Km and the EyeSys CAS were quite high. However, the correlation coefficients for K1, K2, AK, As or steep meridian axis (Ax) readings taken intraoperatively by IOPAR CTS were quite low when compared to the readings taken by either the Auto-Km or EyeSys CAS three months postoperatively.
  
  
  CONCLUSIONS
  We found IOPAR CTS, relatively difficult to perform in the operating room during refractive surgical procedures and not useful clinically in predicting the postoperative topographical changes induced by ICRS or PRK procedure. Further studies are required to establish the efficacy and reproducibility of the instrument.
authors.affiliation: Mount Sinai School of Medicine, Department of Ophthalmology, New York, NY 10029, USA.
authors.forename: O O
authors.initials: OO
authors.lastname: Uçakhan
authors.forename: G J
authors.initials: GJ
authors.lastname: Sternberg
authors.forename: J
authors.initials: J
authors.lastname: Sokol
authors.forename: S E
authors.initials: SE
authors.lastname: Brodie
authors.forename: P A
authors.initials: PA
authors.lastname: Asbell
mesh_terms: D000328:Adult; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D019781:Corneal Topography; D005260:Female; D006801:Humans; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D018903:Photorefractive Keratectomy; D011184:Postoperative Period; D011379:Prognosis; D054140:Refractive Surgical Procedures; D015203:Reproducibility of Results