Screening for Glaucoma Using FDT-Perimetry and Polarimetric Measurements in Different Stages of Glaucomatous Optic Nerve Damage

Abstract

Abstract: : Purpose: To evaluate the utility of combined use of FDT-perimetry and polarimetry in groups of patients with different severity of glaucomatous optic nerve damage. Methods: The study included a heterogeneous group of 351 glaucomatous eyes. Based on color stereo optic disc photographs and morphological criteria (Jonas: 1988) the total glaucoma group was divided into four subgroups (stage1: loss of normal configuration of the neuroretinal rim, n=151; stage2: notching of the neuroretinal rim, n=111; stage3: advanced glaucomatous cupping, n=59; stage4: far advanced glaucomatous cupping, n=30). 195 normal eyes served as control group. All controls and patients underwent complete ophthalmological examinations including conventional white-on-white perimetry, tonometry, FDT-perimetry (screening protocol: C-20-5) and polarimetry (GDx). Criteria for exclusion: previous FDT perimetry, optic discs larger than 4 mm², media opacities, patients younger than 30 years or older than 66 years, low image quality. FDT-Viewfinder and SPSS was used for case-wise recalculation of all missed localized probability levels to create a FDT screening score. Diagnostic value of procedures has been judged from area under the ROC-curve and sensitivitiy at specificity= 90%. In addition to single parameters’ validity, the value of a discriminant function (D) has been calculated for all individuals with the scores delivered by FDT-perimetry and polarimetry. Results: Sensitivities in patient groups are given in the table. In glaucoma group "stage1", area under ROC is significantly larger for GDx-number than for FDT-score. In other glaucoma groups, however, ROC of the FDT-score is significantly above the GDx-number. A combination of both methods with a discriminant formula is superior to single tests in all subgroups. Conclusions: FDT-perimetry and GDx-polarimetry are able to detect a portion of the present glaucoma patients. The study shows that combination of different techniques, which are able to uncover different glaucoma properties can result in an improved power of glaucoma detection. Sensitivities in glaucoma patient groups (in%)  

Keywords: imaging/image analysis: clinical • nerve fiber layer • perimetry