(1) Background: to investigate the correlation between structural (retinal ganglion cells and retinal nerve fibers) and functional alterations analyzed point-by-point in the central 10 degrees of the visual field of patients with advanced glaucoma using Humphrey 10-2 visual field tests. (2) Methods: Single-center prospective cohort study carried on from October 2018 to February 2019 at the Croix-Rousse hospital, Lyon, France. The primary outcome measure was the point-by-point correlation between retinal sensitivity (Humphrey 10-2) and retinal ganglion cell complex (GCC) thickness. (3) Results: 29 eyes of 27 patients were examined. Of these, 15 eyes had a mean deviation (MD) less than −20 dB. There were statistically significant linear relationships between GCC thickness and 10-2 visual field sensitivity for several points in the lower part of the visual field, with lower retinal sensitivity being associated with thicker GCC layers. There were no strong linear relationships or statistically significant correlations in the other regions of the visual field. For the patients with MD < −20 dB, there were statistically significant linear relationships between GCC thickness and 10-2 visual field sensitivity for several points in the superior nasal region. Retinal sensitivity was not correlated with retinal nerve fibre layer thickness. (4) Conclusions: In this study of patients with advanced glaucoma, GCC thickness was linearly associated with 10-2 visual field sensitivity in certain regions, negatively for patients with less-severe glaucoma. The initial thickening raises questions about the apoptosis mechanism, while the thinning observed in the most severe cases is consistent with the ganglion cell death identified on visual field tests.