Share Email Print

Proceedings Paper

Depth-adjusted thermal keratoplasty using a cw diode laser and a new focusing handpiece
Author(s): Benedikt J. Jean M.D.; Thomas Bende; Theo Oltrup; Michael Matallana; Rudolf Walker
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Thermal keratoplasty is currently performed with a Ho:YAG laser at 2.1 micrometer wavelength. Long term stability critically depends upon the coagulation depth of each cone and thus upon emission wavelength, absorption and focusation, all contributing to controlled collagen shrinkage in order to induce central corneal steepening. Cw properties meet coagulation requirements more effectively by avoiding tissue cooling by thermal diffusion as well as peak temperatures of pulsed lasers. Both of these factors interfere negatively with collagen shrinkage. Therefore, a cw diode laser has been developed, emitting at 1.9 micrometer (absorption in water, comparable to Ho:YAG) with a maximal energy output of 400 mJ. For corneal application, the laser was coupled into a depth adjustable handpiece which allows the user to react to corneal thickness (maximal in the 6 h position) and its interindividual variation, covering a depth range between 350 micrometer and 800 micrometers. The histology of 10 porcine and 6 human cadaver corneas coagulated in vitro, revealed a similar spot geometry compared to conventional Ho:YAG radiation if the same total energy is applied. Higher corrections and better long term stability appear to be clinically achievable.

Paper Details

Date Published: 17 May 1996
PDF: 7 pages
Proc. SPIE 2673, Ophthalmic Technologies VI, (17 May 1996); doi: 10.1117/12.240049
Show Author Affiliations
Benedikt J. Jean M.D., Univ. Tuebingen Augenklinik (Germany)
Thomas Bende, Univ. Tuebingen Augenklinik (Germany)
Theo Oltrup, Univ. Tuebingen Augenklinik (Germany)
Michael Matallana, Univ. Tuebingen Augenklinik (Germany)
Rudolf Walker, Univ. Tuebingen Augenklinik (Germany)

Published in SPIE Proceedings Vol. 2673:
Ophthalmic Technologies VI
Jean-Marie A. Parel; Karen Margaret Joos M.D.; Pascal O. Rol, Editor(s)

© SPIE. Terms of Use
Back to Top