Comparative Study of Macular Ganglion Cell-Inner Plexiform Layer and Peripapillary Retinal Nerve Fiber Layer Measurement: Structure-Function Analysis

PURPOSE. We explored and compared the relationships between the visual field (VF) sensitivities assessed by standard automated perimetry (SAP), and the ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thicknesses as measured by Cirrus high-definition optical coherence tomography (HD-OCT) in glaucomatous eyes. METHODS. We enrolled 213 eyes of 213 patients with glaucoma. The thicknesses of the average/sectoral GCIPL and pRNFL were measured by Cirrus HD-OCT. The mean sensitivity (MS) of 24-2 SAP was recorded on decibel and 1/L scales. The topographic relationships between structure and function were investigated. RESULTS. Statistically significant correlations between the corresponding VF sensitivity and the macular GCIPL thickness were found in all GCIPL sectors. Among six GCIPL sectors, the strongest association was observed between superonasal center MS and inferotemporal GCIPL thickness. In comparative analysis, the association between the central cluster MS and average GCIPL thickness was significantly stronger than that of temporal pRNFL thickness using the decibel scale (P < 0.001). The association between regional VF sensitivities, and the inferior hemifield and inferior GCIPL thicknesses were significantly stronger than those of the corresponding pRNFL thickness using the decibel scale (P = 0.001 and 0.007). CONCLUSIONS. The average and sectoral GCIPL thicknesses determined by Cirrus HD-OCT were associated significantly with global and regional VF sensitivity in patients with glaucoma. The macular GCIPL thickness values may provide more valuable information than temporal pRNFL thickness values for understanding the structure-function relationships of the macular region.