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Abstract #91750 Published in IGR 21-4
A comparison of optic disc area measured by confocal scanning laser tomography versus Bruch's membrane opening area measured using optical coherence tomography
Cazana IM; Böhringer D; Reinhard T; Evers C; Engesser D; Anton A; Lübke JBMC Ophthalmology 2021; 21: 31
BACKGROUND: Precise optic disc size measurements based on anatomically exact disc margins are fundamental for a correct assessment of glaucoma suspects. Computerized imaging techniques, such as confocal-scanning-laser-tomography (CSLT), which applies operator defined boundaries and optical-coherence-tomography (OCT), which incorporates an alternative detectable landmark (Bruch's-membrane-opening (BMO)), have simplified the planimetry of the optic disc and BMO-area, respectively. This study's objectives are to compare both modalities for area and to define a threshold for macro-BMO using BMO-OCT. METHODS: Retrospectively, patients that simultaneously received CSLT and BMO-OCT scans were included. Their images were correlated and agreement was determined using Bland-Altman-analysis. The diagnostic power of a macro-BMO threshold using OCT was derived after creating a receiver-operating-characteristics-curve using the well-established analogous CSLT threshold (2.43 mm). RESULTS: Our study included 373 eyes with a median optic disc area by CSLT/ BMO-area by OCT of 2.56 mm and 2.19 mm respectively. The Bland-Altman-analysis revealed a systematic deviation with a diverging tendency with increasing area, which enabled the creation of the following mathematical relation: disc-area (CSLT)*0.73 + 0.3 = BMO-area (OCT). BMO-area of 2.19 mm showed the best diagnostic power for identifying macro-BMOs using OCT (sensitivity: 75%, specificity: 86%). CONCLUSIONS: Area measurements (CSLT optic disc area vs. BMO-area by OCT) showed a systematic deviation with a divergent tendency with increasing size. Our mathematical equation offers an estimated comparison of these anatomically diverse entities. Considering BMO-OCT´ anatomical accuracy, the 2.19 mm threshold may improve discernment between glaucoma suspects and norm variants.
Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106, Freiburg, Germany. ioana.maria.cazana@uniklinik-freiburg.de.
Full articleClassification:
6.9.1.1 Confocal Scanning Laser Ophthalmoscopy (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)
2.12 Choroid, peripapillary choroid, peripapillary atrophy (Part of: 2 Anatomical structures in glaucoma)
