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JS Schuman, T Farra, G Wollstein, E Hertzmark, JG Fujimoto, CG Mattox, AD Kolbe; OCT and HRT Optic Nerve Head Assessment: A Comparison of Structural and Clinical Parameters . Invest. Ophthalmol. Vis. Sci. 2002;43(13):261.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the relationship between ONH parameters generated by the OCT2 or OCT3 (Optical Coherence Tomography 2 or 3, Zeiss Ophthalmic Systems, Dublin, CA) and HRT (Heidelberg Retina Tomograph, Heidelberg Engineering, Germany). To investigate the association of OCT and HRT ONH parameters with perimetric measures of visual function and with glaucoma status. Methods: Subjects were enrolled consecutively and each subject was imaged on a given day with OCT and HRT. For the HRT, 3 images were taken for each eye at a 15 degree scan angle and mean topographic images were generated using software version 2.01. A contour line was drawn around the ONH by a single observer and global parameters were calculated using the standard reference height. For the OCT, six radial scans centered on the ONH were taken and the OCT software automatically defined the ONH. In this software, the edge of the disc was detected by automatically identifying the end of the retinal pigment epithelium/choriocapillaris reflection; there was no user input in image processing or analysis. For each eye, each instrument generated disc area, cup area, rim area, cup/disc area ratio, cup volume and rim volume. Each subject underwent automated perimetry and a complete ophthalmic clinical examination. Parameters were compared using repeated measures regression and logistic regression. Results: Data are reported here for the OCT2-HRT portion of this study. 174 eyes of 129 subjects were imaged (mean age 61.1 +/- 13.1; 21-92). Significant correlations between OCT and HRT measures were observed for all parameters: disc area (r=0.73, p<0.001), cup area (r=0.87, p<0.001), cup volume (r=0.78, p<0.001), cup/disc area ratio (r=0.79, p<0.001), rim area (r=0.44, p<0.001), and rim volume (r=0.42, p<0.001). Both devices were significantly associated with glaucoma disease status (p=0.0001) MD (p=0.0001) and PSD (p=0.0001). Conclusion: OCT automated disc analysis, which characterized the ONH with no user input, performed in a fashion similar to HRT, which required a manually drawn contour line. Both devices showed similar associations with glaucoma status and perimetric functional glaucoma assessment. OCT ONH assessment was completely objective and quantitative, and had the advantage of eliminating operator induced variability in ONH analysis.
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