Thermische schadigung des hornhautendothels bei der dioden- laserthermokeratoplastik

Translated title of the contribution: Thermal damage of the corneal endothelium in diode laser thermokeratoplasty

Norbert Koop*, Christopher Wirbelauer, Andreas Tüngler, Gerd Geerling, Gerd Otto Bastian, Ralf Brinkmann

*Corresponding author for this work
3 Citations (Scopus)

Abstract

Laser thermokeratoplasty (LTK) can be applied for correction of hyperopia and astigmatism by means of concentrically placed coagulations. Because of the temperature rise during coagulation, damage of the endothelial cells directly below the irradiated areas is possible. In this study, we examined the extent of the thermally denatured zones for different laser parameters and the threshold of thermal endothelial damage as a function of of temperature and duration of elevated temperatures. The threshold for thermal damage of endothelial cells was determined in isotonic NaCl solution for temperature exposures of 10 s and 1 min in a water bath. To determine the damage zones, corneas were irradiated under standardized conditions with a continuously emitting infrared (cw-IR) laser diode at various wavelengths and different power values and were stained after preparation with trypan blue and alizarine red. The extensions of the damage zones were compared with calculated isotherms. Fifty percent cell damage was found at temperatures of 65 °C for heating times of 10 s and at 59°C for 1 min. With thicker corneas, less laser power and higher absorption coefficients, the damage zone was reduced. The damage range determined corresponded to the calculated isotherms of 60 °C and 70 °C. Regarding clinical LTK, a loss of endothelial cells can be predicted and minimized or totally avoided by choosing the appropriate irradiation parameters.

Translated title of the contributionThermal damage of the corneal endothelium in diode laser thermokeratoplasty
Original languageGerman
JournalOphthalmologe
Volume96
Issue number6
Pages (from-to)392-397
Number of pages6
ISSN0941-293X
DOIs
Publication statusPublished - 06.1999

Research Areas and Centers

  • Academic Focus: Biomedical Engineering

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