  In a recent paper by Menzel et al. (Opt. Exp. 22, 9971 (2014)), its authors
analyze the spectral red-shift effect of plasmonic resonances of metallic
nano-antennas between the far-field and near-field regimes. Here, we
demonstrate that their interpretation of this effect is done under the same
perspective as one recently reported in Langmuir 29, 6715 (2013); however, the
former is incomplete and needs some remarks and clarifications which require
additional relevant concepts and arguments of physical significance.
