Real Time Speckle Monitoring to Control Retinal Photocoagulation

Katharina Bliedtner, Eric Seifert, Ralf E. D. Amelink A. Brinkmann


Photocoagulation is a treatment modality for several retinal diseases. Intra- and inter-individual variations of the retinal absorption as well as ocular transmission and light scattering makes it impossible to achieve a uniform effective exposure with one set of laser parameters. To guarantee a uniform damage throughout the therapy a real-time control is highly requested. Here, an approach to realize a real-time optical feedback using dynamic speckle analysis in-vivo is presented. A 532 nm continuous wave Nd:YAG laser is used for coagulation. During coagulation, speckle dynamics are monitored by a coherent object illumination using a 633 nm diode laser and analyzed by a CMOS camera with a frame rate up to 1 kHz. An algorithm is presented that can discriminate between different categories of retinal pigment epithelial damage ex-vivo in enucleated porcine eyes and that seems to be robust to noise in-vivo. Tissue changes in rabbits during retinal coagulation could be observed for different lesion strengths. This algorithm can run on a FPGA and is able to calculate a feedback value which is correlated to the thermal and coagulation induced tissue motion and thus the achieved damage.
Original languageEnglish
Title of host publicationNovel Biophotonics Techniques and Applications IV
EditorsArjen Amelink
Publication date28.07.2017
ISBN (Print)978-151061284-6
Publication statusPublished - 28.07.2017
- ICM-International Congress Center Munich, Munich, Germany
Duration: 25.06.201729.06.2017
Conference number: 137548

Research Areas and Centers

  • Academic Focus: Biomedical Engineering


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