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24th Annual Meeting of the German Retina Society

German Retina Society

17.06. - 18.06.2011, Aachen

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Comparison of real-time temperature distribution during laserphotocoagulation and high-resolution OCT in patients with PDRP

Meeting Abstract

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  • Johann Roider - Universitäts-Augenklinik Schleswig-Holstein, Kiel
  • S. Koinzer - Universitäts-Augenklinik Schleswig-Holstein, Kiel
  • M. Bever - Institut für Biomedizinische Optik, Lübeck
  • L. Ptaszynski - Institut für Biomedizinische Optik, Lübeck
  • K. Schlott - Institut für Biomedizinische Optik, Lübeck
  • A. Baade - Institut für Biomedizinische Optik, Lübeck
  • L. Portz - Institut für Biomedizinische Optik, Lübeck
  • S. Luft - Institut für Biomedizinische Optik, Lübeck
  • R. Birngruber - Institut für Biomedizinische Optik, Lübeck
  • R. Brinkmann - Institut für Biomedizinische Optik, Lübeck

German Retina Society. 24th Annual Conference of the German Retina Society. Aachen, 17.-18.06.2011. Düsseldorf: German Medical Science GMS Publishing House; 2011. Doc11rg51

doi: 10.3205/11rg51, urn:nbn:de:0183-11rg511

This is the English version of the article.
The German version can be found at: http://www.egms.de/de/meetings/rg2011/11rg51.shtml

Published: June 15, 2011

© 2011 Roider et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Introduction: The amount of tissue damage in retinal photocoagulation is correlated to the laser power chosen. It is adapted between each laser shot, if necessary. Both absorption of the choroid and the RPE and the transmission of the lens can vary totally by a factor of three. As a result over- or undertreatment can occur. Therefore a method would be desired, where each individauel laser effect can be adjusted during lasercoagulation.

Methods: A method based on optoacoustics has been developped, to measure the temperature during laser photocoagulation non invasively in the laser spot. Temperatures during lasercoagulation has been measured in 105 lesions (300 µm, 200 ms) in 14 patients with PDRP. High resolution OCT images of the laser spot have been obtained over a period of 4 months.

Results: At 62 Celsius degree OCT changes were minimal after 1 hour, but very pronounced after 1 week. Temperatures of 75 C degree result in a bubble like RPE detachment and a condensed photoreceptor layer. At 92C degree the centre of the lesion was attached and surrounded by a detached ring. At 97 Celsius degree the lesions do not show a signal enhancement . Size and degree of damage are correlated to the temperature.

Conclusion: The OCT image correlates to the temperature measured. OCT is more accurate than ophthalmoscopic judging the degree of blanching. Online temperature measurement is suited for an individual calibration of single laser spots.