21 November 2017 Power-controlled temperature guided retinal laser therapy
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Laser photocoagulation has been a treatment method for retinal diseases for decades. Recently, studies have demonstrated therapeutic benefits for subvisible effects. A treatment mode based on an automatic feedback algorithm to reliably generate subvisible and visible irradiations within a constant irradiation time is introduced. The method uses a site-individual adaptation of the laser power by monitoring the retinal temperature rise during the treatment using optoacoustics. This provides feedback to adjust the therapy laser power during the irradiation. The technique was demonstrated on rabbits in vivo using a 532-nm continuous wave Nd:YAG laser. The temperature measurement was performed with 523-nm Q-switched Nd:YLF laser pulses with 75-ns pulse duration at 1-kHz repetition rate. The beam diameter on the fundus was 200    μ m for both lasers, respectively. The aim temperatures ranged from 50°C to 75°C in 11 eyes of 7 rabbits. The results showed ophthalmoscopically invisible effects below 55°C with therapy laser powers over a wide range. The standard deviation for the measured temperatures ranged from 2.1°C for an aim temperature of 50°C to 4.7°C for 75°C. The ED50 temperature value for ophthalmoscopically visible lesions in rabbits was determined as 65.3°C. The introduced method can be used for retinal irradiations with adjustable temperature elevations.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Alexander Baade, Alexander Baade, Claus von der Burchard, Claus von der Burchard, Meike Lawin, Meike Lawin, Stefan Koinzer, Stefan Koinzer, Benedikt Schmarbeck, Benedikt Schmarbeck, Kerstin Schlott, Kerstin Schlott, Yoko Miura, Yoko Miura, Johann Roider, Johann Roider, Reginald Birngruber, Reginald Birngruber, Ralf Brinkmann, Ralf Brinkmann, } "Power-controlled temperature guided retinal laser therapy," Journal of Biomedical Optics 22(11), 118001 (21 November 2017). https://doi.org/10.1117/1.JBO.22.11.118001 . Submission: Received: 31 May 2017; Accepted: 25 October 2017
Received: 31 May 2017; Accepted: 25 October 2017; Published: 21 November 2017

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