Correlation between structural and functional tests in primary open-angle glaucoma

PURPOSE: The objective of this study was to evaluate the correlation between functional (visual field and visual evoked po-tentials [VEP]) and structural (optical coherence tomography [OCT]) test findings in primary open-angle glaucoma (POAG) patients.
METHODS: A total of 56 eyes of 28 patients with POAG were tested. A complete ophthalmological examination, with a visual field test, OCT exam, and VEP recording, was performed. Measurements of the intraocular pressure, N75-P100 amplitude, N75 and P100 latency of VEP, retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness, mean deviation (MD), pattern standard deviation (PSD), and visual field index (VFI) of the visual field were recorded. The parameters were assessed for correlations.
RESULTS: The RNFL and PSD parameters were negatively correlated (r=-0.324, p=0.015). The RNFL was positively correlated with the N75-P100 amplitude (r=0.586, p=0.000). The GCC demonstrated a positive correlation with the MD and a negative correlation with the PSD (r=0.431, p=0.001; r=-0.264, p=0.049, respectively). The P100 latency and the VFI were negatively correlated (r=-0.344, p=0.009). The N75 latency was positively correlated with the RNFL and the GCC (r=0.375, p=0.004; r=0.324, p=0.015, respectively).
CONCLUSION: The results of this study indicated that the OCT and visual field findings showed good structure-function cor-relation. The N75-P100 amplitude and P100 latency of VEP was correlated with OCT and visual field parameters.