title: Online optical coherence pachymetry as a safety measure for laser in situ keratomileusis treatment in 1859 cases.
abstract: OBJECTIVE
  To evaluate the reliability and applicability of online optical coherence pachymetry (OCP) (OCPonline, Heidelberg Engineering GmbH) integrated into the Zyoptix 217z100 excimer laser platform (Bausch & Lomb) under routine clinical conditions.
  
  
  METHODS
  Private laser clinic, Munich, Germany.
  
  
  METHODS
  Between July 2004 and June 2006, 1859 consecutive eyes having laser in situ keratomileusis (LASIK) using the Zyoptix 217z100 excimer laser platform had preoperative pachymetry with the Orbscan II (Bausch & Lomb) and DGH II (Pachette 2, DGH Technology, Inc.) and continuous intraoperative online OCP with the OCPonline. Preoperative pachymetry values and actual flap thicknesses with the Hansatome and Zyoptix XP microkeratomes (both Bausch & Lomb) and the IntraLase FS30 femtosecond laser keratome (IntraLase Corp.) were evaluated.
  
  
  RESULTS
  Preoperative pachymetry values showed a high correlation between the OCPonline device and the Orbscan II (R(2) = 0.78, difference = 0.37%) and DGH II (R(2) = 0.77, difference = 0.69%). The OCPonline measurements resulted in a mean flap thickness of 121.4 microm +/- 19.1 (SD) with the Hansatome (160 microm head), 126.5 +/- 15.5 microm with the Zyoptix XP (120 microm head), and 121.7 +/- 14.7 microm with the IntraLase FS30 (110 microm flap thickness). A correlation between the calculated laser ablation depth and the measured stromal thinning was established.
  
  
  CONCLUSIONS
  OCPonline technology provided reliable intraoperative noncontact pachymetry measurements integrated into a clinical flow, indicating the technology has the potential to improve the safety of corneal ablation procedures.
authors.affiliation: Tübingen University Eye Hospital, Tübingen, Germany. irmingard.neuhann@med.uni-tuebingen.de <irmingard.neuhann@med.uni-tuebingen.de>
authors.forename: Irmingard M
authors.initials: IM
authors.lastname: Neuhann
authors.forename: Barbara A M
authors.initials: BA
authors.lastname: Lege
authors.forename: Markus
authors.initials: M
authors.lastname: Bauer
authors.forename: Joerg M
authors.initials: JM
authors.lastname: Hassel
authors.forename: Anton
authors.initials: A
authors.lastname: Hilger
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Neuhann
mesh_terms: D001837:Body Weights and Measures; D003315:Cornea / Q000000981:diagnostic imaging*; D003319:Corneal Stroma / Q000473:pathology*; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D016343:Monitoring, Intraoperative / Q000379:methods; D009216:Myopia / Q000601:surgery*; D013524:Surgical Flaps / Q000473:pathology; D041623:Tomography, Optical Coherence / Q000379:methods*; D014463:Ultrasonography