Relationship between indices of Humphrey perimetry and Frequency Doubling Technology Perimetry in glaucoma

To study whether the correlation between indices of Humphrey perimetry and Frequency Doubling Technology (FDT) perimetry differs in the early and later stages of glaucoma.

This study included 200 eyes of 200 patients with primary open-angle glaucoma or normal-tension glaucoma. The eyes were classified into the early and later stages by the median value (-4.51 dB) (Classification 1; n = 100 and 100, respectively) or the average value of the maximum and minimum values (-11.90 dB) (Classification 2; n = 165 and 35, respectively) of mean deviation (MD) obtained from a set of measurements with the Humphrey Full-Threshold 30-2 program in all eyes. The correlation between MD (H-MD) or pattern standard deviation (PSD) (H-PSD), as obtained from another set of measurements with the Humphrey Full-Threshold 30-2 program, and MD (F-MD) or PSD (F-PSD), as calculated by the Full-Threshold N-30 program of FDT perimetry, were evaluated using linear regression analysis.

Overall, H-MD and H-PSD significantly correlated with F-MD (r = 0.713; P < 0.001) and F-PSD (r = 0.731; P < 0.001), respectively. In each of Classifications 1 and 2, H-MD and H-PSD significantly correlated with F-MD and F-PSD, respectively, both in the early and later stages. However, in each classification, the correlation between H-MD and F-MD differed significantly between the two stages (Classification 1; P < 0.001; Classification 2, P = 0.003), while the correlation between H-PSD and F-PSD did not differ significantly between the two stages.

The degree of correlation between H-MD and F-MD differed between the early and later stages of glaucoma.