Correlation between visual field index and ganglion cell complex parameters, global loss volume and focal loss volume, measured by RTVueTM OCT: interim analysis

Abstract

Purpose To evaluate the correlation between visual field index (VFI%) and ganglion cell complex (GCC) parameters: global loss volume (GLV%) and focal loss volume (FLV%) in glaucomatous patients. Methods Prospective study including both eyes of 31 glaucomatous patients with a repeatable abnormal Standard Automated Perimetry (SAP) and a local visual field defect in at least one eye. Visual field (VF) examination was performed using Humphrey SAP. OCT imaging was obtained by an experienced technician and using RTVue Spectral Domain OCT. VFI% from VF examination and GLV% and FLV% from RTVue OCT were taken into account for further statistical analysis. Pearson correlation coefficient was used to assess the correlation between different parameter. Results The mean age was 56 ± 14 yrs. Only 49 of the total 62 visual fields showed reliable and repeatable defect with an abnormal GHT (Abn VF). These VF were taken into account for the correlation test. The remainders (NL VF) were used as controls. The mean VFI% in Abn VF was 79.8 ± 21%. The mean of GLV% was 6.0 ±4.1 and the mean of FLV % was 19.6±11. The Pearson correlation showed no correlation between VFI% and GLV% (p=0.07). There was a correlation between VFI% and FLV% (p<0.01). Conclusion To date, in this interim analysis, we found only a correlation between VFI% and FLV%. It might refer that FLV parameter is more influenced by the focal defect in the VF.