Abstract
Purpose: :
To investigate the impact of typical scan score (TSS) on discriminating glaucoma patients and healthy controls.
Methods: :
Fifty-five glaucoma patients and 40 healthy controls were recruited from the Erlangen Glaucoma Registry for this study. Standard static white on white perimetry, 24-h IOP profile, stereographic optic disc slides, scanning laser polarimetry GDx VCC (Carl Zeiss Meditec, Inc., Dublin, CA) and optical coherence tomography (Spectralis HRA+OCT, Heidelberg Engineering, Germany) were performed in all patients and controls. For the controls only scans with TSS=100 were accepted. The glaucoma patients were divided into three subgroups according to their TSS (TSS=100; 99 ≥ TSS ≥ 80, TSS < 80). Receiver operating characteristic (ROC) curves were constructed for mean RNFL values, sector data and for the NFI. Sensitivity was estimated at ≥ 90% and ≥ 80% of specificity to compare the discriminating ability of each imaging modality.
Results: :
For discrimination between healthy and glaucomatous eyes in GDx VCC the NFI demonstrated the largest area under the ROC curve (AUROC ± SE, Sensitivity at 90% Specificity; 0.996 ± 0.005;100%) for very typical scans (TSS of scans of both normals and perimetric glaucomas were TSS=100), followed by the inferotemporal sector (0.993 ± 0.007;100%) and the TSNIT average (0.985 ± 0.012;95%). In Spectralis-OCT the nasosuperior, inferotemporal sector, superior quarter showed the largest AUROC (1.000 ± 0.000;100%) followed by the TSNIT average (0.996 ± 0.005,100%). For atypical scans (TSS of glaucomatous scans were TSS < 80), in GDx VCC the NFI demonstrated the largest AUROC (0.954 ± 0.024;85%) followed by the supernasal sector (0.880 ± 0.050;65%) and the TSNIT average (0.645 ± 0.084;40%). In Spectralis-OCT the TSNIT average showed the largest AUROC (0.965 ± 0.033;95%) followed by the inferotemporal sector (0.955 ± 0.032,85%).
Conclusions: :
Low TSS is associated with a decrease in diagnostic accuracy for discriminating healthy and glaucomatous eyes in both GDx VCC and much less in Spectralis-OCT. Diagnostic accuracy of Spectralis-OCT was superior to GDx VCC for low TSS.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • optic disc