Upgrading wide field contact specular microscope

• Published in: Acta ophthalmologica (Oxford, England) Vol. 93; no. S255
• Main Authors: Hor, G., Gavet, Y., Gain, P., Thuret, G., Bernard, A., Pinoli, J.C.
• Format: Journal Article
• Language: English
• Published: Malden Wiley Subscription Services, Inc 01.10.2015
• Subjects: Ophthalmology
• ISSN: 1755-375X; 1755-3768
• DOI: 10.1111/j.1755-3768.2015.0704

Purpose Non‐contact specular microscopes (SM) developed 25 years ago highly facilitated image acquisition while eliminating contaminations risk. Nevertheless their very small field of observation (SM Topcon SP2000: 0.1 mm2) constitute major limitations for the assessment corneas. Aim To upgrade a wide field contact SM with a digital camera and dedicated software. Methods The original camera film was replaced by a digital camera (Canon EOS 6D with full‐frame 35 mm sensor) connected to a computer. The new camera was fixed on the SM (Konan SP5500, ×40 zoom) with 3D print custom adaptor and uses its optics. After acquisition of wide field images (0.6 mm2), they were processed using a segmentation algorithm (watershed with markers method). Software, using several libraries (ITK, OpenCV, Qt, MySQL), has been developed allowing the acquisition of images (camera control), image processing, and storage of results in a database. Results A segmented image showing only cell borders in black over white background and document which presents ECD number (1000 cells counted) and cell's characteristics showing quality of cells (regarding their size). Stored in a database, these results are available for operators. Conclusions The upgraded wide field contact SM counts a great number of cells. Consequently, it estimates the ECD with less bias than other methods. Also, it can be used for the assessment of heterogeneous endothelium like in Fuchs corneal endothelial diseases for which noncontact SM are obviously unsuited. GRANT: ANR 2012 CORIMMO project.