Mapping standard automated perimetry to the peripapillary retinal nerve fiber layer in glaucoma

PURPOSE. To establish a map relating visual field (VF) test points to corresponding areas of the retinal nerve fiber layer (RNFL) measured with optical coherence tomography (OCT) in patients with glaucomatous optic neuropathy. METHODS. One hundred four consecutive subjects with open-angle glaucoma were prospectively selected. All subjects underwent standard automated perimetry (SAP) and imaging with OCT. Factor analyses of the mean thresholds for the SAP test points were performed, independently for each hemifield, to define regions of related points. Pearson correlations were then calculated between the VF regions and peripapillary RNFL thickness measured with OCT at each of the 12 clock-hour positions. A map relating the VF regions to the OCT sectors was plotted based on the strongest correlations between both techniques. RESULTS. Factor analysis distributed the VF points into five VF regions for each hemifield. A slightly asymmetric distribution of VF regions was obtained for the upper and lower points, with respect to the horizontal meridian. Mild to moderate correlations were observed between the VF regions and RNFL thickness. The superior VF regions and RNFL segments correlated most strongly at the 6-and 7-o'clock positions (r = 0.4-0.5). CONCLUSIONS. There was a moderate association between the VF regions and the RNFL thickness in patients with glaucomatous optic neuropathy, as measured by OCT. Within sectors of the RNFL, there was some overlap in the representation of the VF regions. The map obtained validates previously reported clinical findings and contributes to a better understanding of the relationship between structure and function in patients with glaucoma.