Online optical coherence pachymetry as a safety measure for laser in situ keratomileusis treatment in 1859 cases
Accepted 14 April 2008.
Purpose
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.
Setting
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 (R2 = 0.78, difference = 0.37%) and DGH II (R2 = 0.77, difference = 0.69%). The OCPonline measurements resulted in a mean flap thickness of 121.4 μm ± 19.1 (SD) with the Hansatome (160 μm head), 126.5 ± 15.5 μm with the Zyoptix XP (120 μm head), and 121.7 ± 14.7 μm with the IntraLase FS30 (110 μm flap thickness). A correlation between the calculated laser ablation depth and the measured stromal thinning was established.
Conclusion
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.
From Tübingen University Eye Hospital (I.M. Neuhann), Tübingen, a private laser clinic (Lege, Bauer, Hassel, T.F. Neuhann), Munich, and Bausch & Lomb Technolas GmbH (Hilger), Feldkirchen, Germany
Corresponding author: I. Neuhann, MD, FEBO, Tübingen University Eye Hospital, Schleichstrasse 12-16, 72076 Tübingen, Germany.
Dr. T.F. Neuhann and Mr. Hassel are scientific consultants to Bausch & Lomb. Mr. Hilger is a Bausch & Lomb employee. No other author has a financial or proprietary interest in any material or method mentioned.
Presented in part at the annual meeting of the American Academy of Ophthalmology, Las Vegas, Nevada, USA, November 2006, and the ASCRS Symposium on Cataract, IOL and Refractive Surgery, San Diego, California, USA, April 2007.
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