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D.J. Mena, W.M. Budde, J.B. Jonas; Optic Disc Morphometry by Optical Coherence Tomography: Is Interactive Correction Necessary? . Invest. Ophthalmol. Vis. Sci. 2004;45(13):5523.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate, in which eyes interactive correction of the outlining of the optic disc by the optical coherent tomograph OCT III (Zeiss–Humphrey) differs from the automatic outlining. Methods: The study included 142 eyes (94 Caucasian subjects; 56 females) undergoing OCT 3 disc imaging (fast scan protocol). The optic disc margin was automatically determined by the software. In a second step, all scans were inspected and the correct position of the edge of the optic disc was interactively corrected by the examiner if necessary. The difference in disc size between the automated determination and the manually corrected determination was assessed. Additionally, confocal laser scanning tomograms (HRT II) and optic disc photographs were obtained. Results: Minor manual corrections were performed in 100 eyes, profound corrections at the nasal sector of the disc in 30 eyes, at the temporal sector of the disc in 2 eyes, and diffusely around the disc in 10 eyes. The mean absolute difference in disc area between the automatic measurements and the interactively corrected determinations was .23 ± .20 mm² (mean ± SD; median: .17; range: 0 – .9 mm²), which amounted to 11.0% ± 10.5% of corrected disc size (7%; 0% – 53%). In 20 (14.1%) eyes, the corrected disc size was larger, in 114 (80.3%) eyes, the corrected disc size was smaller than the automated disc size. The absolute difference exceeded 25% in 18 of the 142 eyes (13%). This high difference group differed significantly (P<.01) from the remaining group in smaller disc area and in nasal prominence as determined by HRT II. No significant influence on the difference between uncorrected and corrected OCT disc area measurements was found for age, gender, presence of glaucoma, refractive error, axial length, keratometric power, and presence and amount of parapapillary atrophy. Correlating OCT disc area measurements with disc area determinations by the HRT II or planimetry of optic disc photographs revealed higher correlation coefficients for the interactively corrected OCT values. Conclusions:Corrected OCT disc area values correlate better with disc area measurements by other techniques than uncorrected OCT measurements. Interactive correction of OCT optic disc examinations may be advisable for discs with prominent borders as in small optic discs or tilted discs. Automatic OCT determination of the optic disc border may not markedly be influenced by presence and amount of parapapillary atrophy.
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