Correlation between Visual Field Index and Other Functional and Structural Measures in Glaucoma Patients and Suspects

PURPOSE: To evaluate the correlation between visual field index (VFI) and both structural and functional measures of the optic disc in primary open angle glaucoma patients and suspects. METHODS: In this retrospective study, 162 glaucoma patients and suspects underwent standard automated perimetry (SAP), retinography, and retinal nerve fiber layer (RNFL) measurement. The optic disc was stratified according to the vertical cup/disc ratio (C/D) and sorted by the disc damage likelihood scale (DDLS). RNFL was measured with the optical coherence tomography. The VFI perimetry was correlated with the mean deviation (MD) and pattern standard deviation (PSD) obtained by SAP, and structural parameters by Pearson's correlation coefficients. RESULTS: VFI displayed strong correlation with MD (R = 0.959) and PSD (R = −0.744). The linear correlations between VFI and structural measures including C/D (R = −0.179, P = 0.012), DDLS (R = −0.214, P = 0.006), and RNFL (R = 0.416, P < 0.001) were weak but statistically significant. CONCLUSION: VFI showed a strong correlation with MD and PSD but demonstrated a weak correlation with structural measures. It can possibly be used as a marker for functional impairment severity in patients with glaucoma.