Superficial and deep macular vessel density (VD) is decreased in eyes with
glaucoma. Superficial VD comprises both the
retinal nerve fiber layer (RNFL) and
ganglion cell/inner plexiform layer (GC/IPL), and various terms have been used previously to describe the layers of macular VD. In our study, we readjusted the macular segmentation. We obtained RNFL and GC/IPL VDs separately to evaluate VD changes of axon versus
soma/dendrite of the retinal ganglion cells (RGCs) in detail. We included 66 eyes of
normal tension glaucoma patients with inferior localized RNFL defects solely impacting the inferior hemiretina. Macular VD was measured as RNFL VD and GC/IPL VD. VD ratio was calculated by dividing the VD from the affected hemiretina by the VD from the unaffected hemiretina. RNFL VD ratio was related to RNFL and GC/IPL thicknesses (p = 0.005, p = 0.001), whereas GC/IPL VD ratio was not (p = 0.596, p = 0.783). A lower GC/IPL VD ratio was associated with lower RNFL VD (p = 0.017) and systemic
hypertension (p = 0.03) in multivariate analysis. Patients with a reduced GC/IPL VD ratio were more prone to poor visual field defects (p = 0.022) and
paracentral scotoma (p = 0.046) and more likely to be on treatment for systemic
hypertension (p = 0.024). Therefore,
glaucoma patients on systemic
hypertension treatment and reduced GC/IPL VD require cautious management.