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S. Miglior, M. Guareschi, L. Buffagni, A. Sala, F. Romanazzi, M. Vavassori; Clinical Ability of GDx VCC and OCT Stratus in Detecting Glaucomatous Visual Field Defects . Invest. Ophthalmol. Vis. Sci. 2005;46(13):4813.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the clinical ability of GDx VCC and OCT Stratus in detecting glaucomatous visual field defects Methods: 196 patients (88 normal, 49 with OHT, 59 with POAG) were enrolled. Normal individuals had a normal 24/II HFA visual field (VF), IOP < 22 mmHg and no family history for glaucoma. OHT patients had an IOP > 21 mmHg on repeated measurements and normal VF. POAG patients had abnormal VF (GHT –outside normal limits– and PSD – p < 0.05 –) and an IOP > 21 mmHg. GDx VCC and OCT stratus examinations were performed three times on the same day and the best image was considered for the analysis. One eye per patient was used for study purposes. TSNIT Average, Superior Average, Inferior Average and NFI were considered to assess the clinical ability of GDx VCC, whereas Average Thickness, Superior Max, Inferior Max, Superior Average, Inferior Average and Min–Max were considered to assess the clinical ability of OCT Stratus. Three analyses were performed: in analysis 1 the Normal group was compared with the POAG group and OHT patrients were excluded; in analysis 2, the OHT patients were included in the normal group; in analysis 3, the OHT patients were included in the POAG group. Sensitivity, specificity, likelihood ratios (LR) and ROC curves were calculated by means of standard procedures. Results: Mean MD and PSD were 0.24 (± 1.18), and 1.57 (± 0.35) in the Normal group, –1.06 (± 1.78) and 2.03 (± 0.73) in the OHT group and –6.7 (± 6.56) and 4.79 (± 3.87) in the POAG group. In analysis 1, NFI (cut–off 30) for the GDx VCC (sensitivity 0.53 – specificity 0.97, +LR 15.41 – –LR 0.49) and Average thickness (cut–off 80) for the OCT Stratus (sensitivity 0.62 – specificity 0.98, +LR 27.59 – –LR 0.38) resulted to have the highest diagnostic ability. At a specificity level of 95% sensitivity of NFI increased to 0.71 and sensitivity of Average Thickness increased to 0.78. The areas under the ROC curves (0.93 for NFI and 0.92 for Average Thickness) were not statistically different. In analysis 2 specificity decreased with both technologies and in analysis 3, sensitivity decreased dramatically. Conclusions: GDx VCC and OCT stratus resulted to be highly specific and moderately sensitive in detecting glaucomatous visual field changes. At a fixed specifity of 0.95 both technologies increased the sensitivity to values > 0.70. However, the inclusion of OHT patients in the analysis strongly affected both sensitivity and specificity.
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