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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 5 — Feb. 28, 2011
  • pp: 4231–4241

Real-time measurement of ArF excimer laser corneal tissue ablation rates using cross-correlation of laser waveforms

Brian T. Fisher and David W. Hahn  »View Author Affiliations


Optics Express, Vol. 19, Issue 5, pp. 4231-4241 (2011)
http://dx.doi.org/10.1364/OE.19.004231


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Abstract

The current popularity of excimer laser refractive surgery suggests a need for continued research and refinements to further improve clinical outcomes. A fundamental limitation of current clinical systems is the lack of real-time feedback specifically addressing the laser-tissue interactions as directly related to laser ablation rates. This paper reports data to assess the feasibility of a novel approach that holds promise as a real-time feedback scheme based on comparison of the incident and reflected laser pulse waveforms, as quantified using a cross-correlation algorithm. The approach is evaluated for ablation of bovine cornea over a range of clinically relevant laser fluences. A linear relationship was observed between several cross-correlation metrics and the directly measured corneal ablation rate, yielding an average RMS predictive error of 3.9% using a 25-shot average reflected waveform. Assessment of the cross-correlation approach for single-shot ablation data revealed a brief transient corresponding to the first few laser pulses, which is attributed to a slight hydration gradient near the surface of the de-epithelialized cornea. Clinical refractive data are necessary to assess the precision of this approach for actual refractive surgery.

© 2011 OSA

OCIS Codes
(160.4890) Materials : Organic materials
(170.1020) Medical optics and biotechnology : Ablation of tissue
(170.3660) Medical optics and biotechnology : Light propagation in tissues
(330.7335) Vision, color, and visual optics : Visual optics, refractive surgery

ToC Category:
Medical Optics and Biotechnology

History
Original Manuscript: December 20, 2010
Revised Manuscript: February 8, 2011
Manuscript Accepted: February 11, 2011
Published: February 17, 2011

Virtual Issues
Vol. 6, Iss. 3 Virtual Journal for Biomedical Optics

Citation
Brian T. Fisher and David W. Hahn, "Real-time measurement of ArF excimer laser corneal tissue ablation rates using cross-correlation of laser waveforms," Opt. Express 19, 4231-4241 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-5-4231


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