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Ivan Tavares, Andre Camargo, Flavio Hirai, Luiz Alberto Melo; Influence of Automated Disc Margin Determination on Stratus OCT Optic Nerve Head Measurements. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1449.
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© ARVO (1962-2015); The Authors (2016-present)
To analyze the influence in the optic disc measurements of the automatically determined edge of the optic nerve head (ONH) and the manually corrected one in cases where the Optical Coherence Tomography did not identify the disc limits correctly.
One-hundred seven of 127 consecutive patients, either normal or glaucomatous, submitted to the Fast Optic Disc Stratus OCT (Carl Zeiss Meditec, Dublin, CA, USA; software 4.0) test were selected. 47 eyes in which either the manual assignment was not necessary or the signal strength was below six were excluded. OCT ONH scans are composed of six radial scans in a spokelike pattern centered on the disc and with each radial scan spaced 30 degrees from one to another. After image acquisition and processing, one expert examiner manually corrected the determination of the edge of the ONH, identified as the end of the retinal pigment epithelium/choriocapillaris layer. Disc Area, Cup Area, Rim Area and Cup/Disc Area Ratio results were compared before and after the optic disc margin manually corrected determination. Paired t-test was performed to evaluate the differences, and P<0.05 was considered statistically significant.
Eighty eyes of 80 people, either normal or glaucomatous, were analyzed. No statistically significant difference (P=0.538) was found when analyzing results obtained with automated and manual determination of Rim Area (mean ± SD): (1.30 ± 0.45 mm2; 1.29 ± 0.39 mm2). Cup Area (1.39 ± 0.58 mm2; 1.31 ± 0.55 mm2), Cup/Disc Area Ratio (0.50 ± 0.16 mm2; 0.49 ± 0.15 mm2) and Disc Area results (2.69 ± 0.55 mm2; 2.60 ± 0.51 mm2) were significantly different, but clinically irrelevant.
The Stratus OCT Optic Nerve Head Report results were little influenced when optic disc limits were manually determined. Therefore the standard automated Stratus OCT disc margin assignment is adequate, and manual edition is not necessary.
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