Value of disc topographic measurements for the discrimination of glaucoma suspects from early primary open angle glaucoma cases: A thin discriminative line.

PURPOSE: To determine the diagnostic value of optic nerve head (ONH) topographic parameters measured by swept-source optical coherence tomography (SS-OCT) in differentiating between early glaucoma cases, glaucoma suspects (GSs), and healthy eyes.

METHODS

The files of GSs, those with an early primary open angle glaucoma (POAG) diagnosis, and healthy eyes were retrospectively screened. Demographic characteristics, retinal nerve fibre measurements, visual field examinations, and ONH topographic parameters, including rim area, disc area, vertical and horizontal cup-to-disc ratios (CDRs), and cup volume, were compared between the groups. A receiver operating characteristic (ROC) curve analysis was performed on the ONH parameters.

RESULTS

A total of 170 eyes from 85 GSs, 114 eyes from 57 patients with a diagnosis of early POAG, and 70 healthy eyes from 48 subjects were included in the study. The median age was 52.1 ± 0.9 years for the POAG group, 60.2 ± 1.1 years for the GS group, and 60.5 ± 1.6 for the controls. In the comparison of the ONH parameters between the groups, only rim area statistically significantly differed between the POAG and GS groups. However, all ONH parameters statistically significantly differed between the GS and control groups (p< 0.05). The mean rim areas of the GS, POAG, and control groups were 1.278 ± 0.055 mm2, 1.073 ± 0.065 mm2, and 1.446 ± 0.055 mm2, respectively, being statistically significantly higher in the controls and lower in the POAG group (p < 0.001). The highest area under the curve (AUC) value belonged to vertical CDR for the discrimination of the eyes with POAG from healthy eyes [0.806 (0.728-0.869, p < 0.001] and rim area for the discrimination of POAG cases and GSs [0.728 (0.650-0.797, p < 0.001].

CONCLUSION

There are significant differences in all ONH parameters between the eyes of GSs and healthy eyes. For the discrimination of early POAG and GS cases, topographic disc parameters may have value. In this study, rim area significantly differed between the GS and POAG groups, and it had the highest AUC value amongst the evaluated ONH parameters in the discrimination of early POAG cases S GSs.