Diagnosis of Glaucoma in the Cases of the Opposed Results of GDx and OCT

Purpose: To investigate the coincidence of visual field loss in cases with different GDx VCC and Stratus OCT results, and to analyze the cause of these differences. Methods: We retrospectively reviewed the medical records of patients who had visited our hospital for glaucoma evaluation from September 2003 to August 2005 for sensitivity, specificity, positive predictive rate, and negative predictive rate of GDx and OCT. In order to analyze the cause of discrepancy between the GDx and OCT results, we divided patients into Group A, consisting of GDx abnormal and OCT normal eyes, and Group B, consisting of GDx normal and OCT abnormal eyes. We compared optic disc tilting, peripapillary atrophy, and cup-disc ratio between the two groups. Results: In cases of differing results between GDx and OCT, sensitivity, specificity, positive predictive rate and negative predictive rate were higher in Stratus OCT than in GDx. Peripapillary atrophy did not represent a statistically significant difference between group A and group B (p=0.601), where as the difference in cup-disc ratio between the two groups was statistically significant (p=0.000). Conclusions: OCT parameters coincided better than GDx with cases having different results on GDx and OCT. In cases with a large cup/disc ratio, there was a tendency to be normal according to GDx and abnormal by OCT.