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Proceedings Paper

Variable depth thermal lesions in rabbit corneas using a tunable thulium fiber laser
Author(s): Nathaniel M. Fried; Guillermo Noguera; Juan Castro-Combs; Ashley Behrens
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Paper Abstract

Laser-induced thermal changes in the cornea have been used clinically for refractive surgery. This study describes the creation of variable depth thermal lesions in the cornea using a tunable Thulium fiber laser. Thermal lesions were created in fresh rabbit corneas, ex vivo, at three different wavelengths (1873 nm, 1890 nm, and 1904 nm) (n=6 corneas each). All other laser parameters were kept fixed with power of 5.5 W, 25-ms exposure time, and 650-&mgr;m diameter spot, yielding a single pulse exposure of 138 mJ, and a fluence of 42 J/cm2. Optical coherence tomography (OCT) and histology were used to measure pre- and post-operative corneal thickness and lesion dimensions. OCT measurements of pre and post-operative corneal thickness and lesion depth (in microns) were: (1873 nm: 450±30, 801±95, 655±51), (1890 nm: 460±27, 618±70, 332±56), (1904 nm: 448+20, 550±42, 245+36), respectively. By comparison, histologic measurements were: (1873 nm: 470+25, 828+21, 540±31), (1890 nm: 457±13, 625±17, 350±43), (1904 nm: 465±40, 627±35, 239±23), respectively. OCT lesion depth measured 82%, 54%, and 45% of corneal thickness, compared to histologic analysis of 65%, 56%, and 38%. This is the first preliminary test of a compact and tunable Thulium fiber laser for creating variable depth thermal lesions in the cornea. The Thulium fiber laser may have potential use as a replacement for the Ho:YAG and diode lasers for thermal keratoplasty.

Paper Details

Date Published: 5 March 2007
PDF: 6 pages
Proc. SPIE 6426, Ophthalmic Technologies XVII, 642613 (5 March 2007); doi: 10.1117/12.697949
Show Author Affiliations
Nathaniel M. Fried, Univ. of North Carolina at Charlotte (United States)
Guillermo Noguera, Johns Hopkins Medical School (United States)
Juan Castro-Combs, Johns Hopkins Medical School (United States)
Ashley Behrens, Johns Hopkins Medical School (United States)

Published in SPIE Proceedings Vol. 6426:
Ophthalmic Technologies XVII
Bruce E. Stuck; Fabrice Manns; Per G. Söderberg; Michael Belkin; Arthur Ho, Editor(s)

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