Abstract
Purpose::
To compare the specificity and sensitivity of the confocal scanning laser ophthalmoscope (HRT-II; Heidelberg Engineering, Heidelberg, Germany) and subjective assessment of optic nerve head (ONH) planimetric photographs in glaucoma patients.
Methods::
Data from 140 glaucomatous and 140 normal eyes of 280 subjects were included in the analysis. All subjects underwent confocal scanning laser ophthalmoscopy with HRT-II and then the optic disc photographs were digitised and analysed with the Topcon ImageNet (TI) system by manually drawing optic disc and cup contour lines. ONH photographs were graded as either normal or glaucomatous appearing in a masked fashion by 2 independent graders. Mean disc area, cup and rim area, and cup-to-disc (C/D) ratio values were compared between each method. The agreement between these parameters was assessed by multiple stepwise backward linear regression analysis and receiver operating characteristic (ROC) curves were constructed for each technique by using the parameter which showed the highest regression coefficient.
Results::
The optic disc area, cup and rim area measurements were significantly smaller in the HRT technique than in the photographic method (all p < 0.001). Linear regression analysis revealed that C/D ratio had the highest regression coefficient. Subsequently, ROC curves constructed depending on the C/D ratio revealed that the specificity of the ONH photography to detect early glaucomatous optic disc changes was 94.8%, with a sensitivity of 62.6%. Using the HRT analysis, the specificity was 95.6% and the sensitivity was 73.9%.
Conclusions::
Similar diagnostic ability was found for ONH photography and HRT-II techniques. However, the sensitivity of HRT-II is higher when compared to that of ONH photography. A combination of subjective ONH evaluation with HRT-II parameters may provide additive information in the diagnosis of glaucoma patients.
Keywords: optic disc • imaging/image analysis: clinical