Comparative study of retinal nerve fibre layer thickness and retinal peripapillary capillary plexus microvascular vessel density: structure–function relationship analysis in glaucoma

Abstract

To investigate whether the retinal peripapillary capillary plexus vessel density (RPCP VD) or the retinal nerve fibre layer thickness (RNFLT) is better in showing the structure–function relationship in glaucoma. Sixty-seven patients with primary open-angle glaucoma (POAG) in one eye and no visual field loss in fellow eye were included in this study. The scans of RPCP VD and RNFLT, and the standard automated perimetry data [including mean deviation (MD), pattern standard deviation (PSD), sector-based pattern deviation (PD) values] were analysed and compared. The global RNFLT was associated with MD (P\u2009=\u20090.035). RNFLTs of the superotemporal, superonasal, inferotemporal and inferonasal quadrants were associated with the corresponding PD (P\u2009=\u20090.004, <0.001, 0.002 and 0.012). The global RPCP VD was found to be associated with MD and PSD (P\u2009=\u20090.030 and 0.049, respectively). RPCP VD of the superotemporal quadrant was associated with PD of the corresponding quadrant, as well as with PSD (P\u2009=\u20090.003 and 0.043, respectively). Remaining RPCP VD values were only associated with the PD values of the corresponding quadrants (P\u2009<\u20090.05). The associations of the RPCP VD with PD were stronger than those of the RNFLT with PD [RPCP VD vs RNFLT: R2\u2009=\u20090.624 vs 0.558 (P\u2009<\u20090.001 for both) for the superotemporal, 0.649 vs 0.552 for the superonasal (P\u2009<\u20090.001 for both), 0.598 vs 0.427 for the inferotemporal (P\u2009<\u20090.001 for both), 0.581 vs 0.408 for the inferonasal (P\u2009<\u20090.001 for both), 0.594 vs 0.068 (P\u2009<\u20090.001 vs 0.098) for the temporal, and 0.338 vs 0.195 (P\u2009<\u20090.001 vs 0.004) for the nasal quadrants]. In conclusion, the VD of RPCP was more informative in terms of the structure–function relationship in POAG. Future prospective follow-up studies with larger sample sizes are required to confirm the findings.