Photocoagulation in rabbits: Optical coherence 
tomographic lesion classification

Kiel – mechentel news – Lasers Surg. Med. publishs in the issue of september the results of the study from S. Koinzer et al. concerning a classification of retinal lesions from rabbits, that is based on optical coherence tomographic (OCT) findings, temperature data, and OCT-follow-up data over 3 months. Therefor 486 photocoagulation lesions in rabbits – the most common animal model to study retinal photocoagulation lesions -(modified Zeiss Visulas® 532 nm CW laser, lesion diameter 133 µm, exposure duration 200 milliseconds or variable, power variable) were analyzed from six eyes of three chinchilla gray rabbits. During the irradiation of each lesion,the scientists uses an optoacoustics-based method to measure the retinal temperature profile. Two hours, 1 week, 1 month, and 3 months after the treatment, they obtained fundus color and OCT (Spectralis®) images of each lesion and classifieted the lesions according to their OCT morphology and correlated the findings to ophthalmoscopic and OCT lesion diameters, and temperatures. The autors declared: “Besides an undetectable lesion class 0, we discerned subthreshold lesions that were invisible on the fundus but detectable in OCT (classes 1 and 2), very mild lesions that were partly visible on the fundus (class 3), and 3 classes of suprathreshold lesions. OCT greatest linear diameters (GLDs) were larger than ophthalmoscopic lesion diameters, both increased for increasing classes, and GLDs decreased over 3 months within each class. Mean peak end temperatures for 200 milliseconds lesions ranged from 61°C in class 2 to 80°C in class 6.” The seven step rabbit lesion classifier is distinct from a previously published human lesion classifier. Threshold lesions are generated at comparable temperatures in rabbits and humans, while more intense lesions are created at lower temperatures in rabbits. The OCT lesion classifier could replace routine histology in some studies, and the presented data may be used to estimate lesion end temperatures from OCT images. Lasers Surg. Med. 45:427-436, 2013. © 2013 Wiley Periodicals, Inc.

Autoren: Koinzer S, Hesse C, Caliebe A, Saeger M, Baade A, Schlott K, Brinkmann R, Roider J. Korrespondenz: Stefan Koinzer, MD, Department of Ophthalmology, University Hospital of Schleswig-Holstein, Campus Kiel, House 25, Arnold-Heller-Str. 3, 24105 Kiel, Germany. E-Mail: koinzer@auge.uni-kiel.de. Studie: Photocoagulation in rabbits: Optical coherence tomographic lesion classification, wound healing reaction, and retinal temperatures. Quelle: Lasers Surg Med. 2013 Sep;45(7):427-36. doi: 10.1002/lsm.22163. Web: http://onlinelibrary.wiley.com/doi/10.1002/lsm.22163/abstract.