Morphology‐function correlation using available clinical parameters describing retinal ganglion cells in glaucoma suspects

Abstract

Aims/Purpose: To determine the morphology‐function correlation using optical coherence tomography (OCT), perimetry and photopic negative responses (PhNR) measurements in glaucoma suspects.Methods: The results of 155 patients who underwent static 24–2 Humphrey visual field test (Optopol), OCT (Optopol) and PhNR (RETeval) examinations were analysed. Patients were divided into two subgroups according to the PhNR wave implicit time, at the minimum value (n = 114) or at 72 ms (n = 41). From perimetry, the mean deviation (MD) and pattern standard deviation (PSD) were analysed. From OCT, retinal nerve fibre layer (RNFL) thickness and ganglion cell complex (GCC) thickness were considered. From the PhNR test, the amplitude of the wave obtained using RETeval was analysed. For the correlation calculations, Spearman's test was used.Results: There was a significant, moderate correlation observed between PhNR at minimum value and PSD (r = 0.2145, p = 0.0006); weak correlations observed between PhNR at minimum value and MD (r = −0.1456, p = 0.0203), RNFL (r = −0.1355, p = 0.0204), GCC (r = −0.1199, p = 0.0406). In case of PhNR at 72 ms, significant moderate correlations were observed for PhNR at 72 ms and PSD (r = 0.2863, p < 0.0001), (RNFL r = −0.2754, p < 0.0001) and (GCC r = −0.2709, p < 0.0001); weak correlation was observed for PhNR at 72 ms and MD (r = −0.1662, p = 0.0219).Conclusions: Based on our analysis, it seems that PhNR at 72 ms correlates better with Retinal Ganglion Cells morphological measures in OCT (GCC and RNFL) and PhNR at minimum value correlates selectively with visual function measured with perimetric PSD exclusively, thus PhNR at minimum value may be more accurate coefficient to be used as a substitute of perimetric parameters.