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J. Xu, H. Ishikawa, G. Wollstein, K. Sung, J. Kim, R. J. Noecker, J. S. Duker, L. Kagemann, J. G. Fujimoto, J. S. Schuman; Automated Extraction of Optic Nerve Head Parameters From Spectral Domain Optical Coherence Tomography. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3658. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To develop a fully automated system for optic nerve head (ONH) quantitative assessment from spectral domain optical coherence tomography (SDOCT) and to evaluate its performance in comparison with the existing ONH assessment techniques - Heidelberg Retina Tomograph (HRT) and Stratus OCT.
Three dimensional OCT images were taken using SDOCT (Cirrus HD-OCT; Carl Zeiss Meditec, Inc. (CZMI), Dublin, CA). Enface images were generated by averaging the intensity values of each A-scan line. A deformable model technique was applied to the enface image to automatically extract the disc margin. Fully automated detection of the internal limiting membrane (ILM) and retinal pigment epithelial (RPE) layers was performed using a software program of our own design. Two points of the cup edge were automatically detected frame by frame and were defined as the cross points of the ONH surface and a reference line that was located 150 microns anterior to the tips of Bruch’s Membrane. The final cup margin was a smoothed contour computed from all cross points. Disc area, rim area, cup area, cup-to-disc (C/D) area ratio, vertical C/D ratio, rim volume and cup volume were computed and compared to corresponding HRT (Heidelberg Engineering, Heidelberg, Germany) and Stratus OCT (CZMI) measurements.
The right eye of each of 19 subjects was enrolled (17 healthy, and 2 glaucomatous eyes). All eyes had Cirrus OCT, HRT and Stratus OCT scanning within one month. SDOCT ONH measurements were statistically significantly smaller than both HRT and Stratus OCT measurements (p<0.002) except for C/D area and vertical ratio, which were similar to both devices, and cup area, which was similar to HRT. All automated SDOCT ONH measurements were moderately to highly and statistically significantly correlated with HRT (Pearson r correlation coefficient range: 0.50-0.93) and Stratus OCT (range: 0.81-0.95) measurements, except for rim volume (r=0.16 for HRT, p=0.52).
Our newly developed software shows the potential to be useful for fully automated ONH assessment with SDOCT.
Clinical Trial: :
www.clinicaltrials.gov NCT 00343746
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