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B. E. Neal, M. Balasubramanian, C. Bowd, G. Vizzeri, P. Sample, R. N. Weinreb, L. M. Zangwill; Stereometric Parameter Trend-Analysis for Detecting Progression Using Three Heidelberg Retina Tomograph Reference Planes. Invest. Ophthalmol. Vis. Sci. 2009;50(13):2246.
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© ARVO (1962-2015); The Authors (2016-present)
To report the sensitivity and specificity of trend analysis of HRT global and sectoral rim area (RA) calculated using 3 reference planes for detecting change and to compare results to results from HRT Topographic Change Analysis (TCA).
HRT global and sectoral (6 sectors defined by HRT software) RA was calculated using the standard HRT reference plane, a reference plane fixed at baseline (Moorfields Reference Plane) and a reference plane set 320 µm below the contour line-independent reference ring. RA progression was defined as a negative slope with p < 5% over the duration of follow up (mean = 3.9 years, 95% C.I. = 3.7, 4.0 years in patients). TCA progression was defined as repeatable change (by HRT convention) ≥ 0.036 mm2 in area of the largest cluster of red super-pixels within the optic disc (contour line) (CAREAdisc).1 Sensitivity was assessed in 36 patient eyes progressed by SAP SITA Guided Progression Analysis (GPA) or by stereophotograph assessment (progressors). Specificity was assessed in 21 normal eyes. We also assessed specificity in 210 apparently stable (by GPA and stereophotography) patient eyes. All participants were recruited from the UCSD Diagnostic Innovations in Glaucoma Study (DIGS). Each eye had ≥ 4 HRT exams (average 4.7, 95% C.I. = 4.6, 4.8).
The RA parameter with the best nominal performance (i.e., sensitivity/specificity trade off) using the standard reference plane was inferonasal. Results from this parameter for the 3 reference planes are shown in the table that also includes results from TCA. TCA was more sensitve and slighly less specific than linear regression (LR) of RA, irrespective of reference plane type.
Regardless of the reference plane used, LR of stereometric RA was poorly sensitive and highly specific, indicating little change over the relatively short follow up provided by the current study. A recent study suggests that longer follow-up may improve the usefulness of this technique.2 In addtion, LR of stereometric parameters theoretically can provide clinically useful descriptions of rate of structural change, information which is currently unavailable in TCA.
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