  We present an investigation into the optical properties of
Nd$_{4}$Ni$_{3}$O$_{8}$ at different temperatures from 300 down to 5~K over a
broad frequency range. The optical conductivity at 5~K is decomposed into
IR-active phonons, a far-infrared band $\alpha$, a mid-infrared band $\beta$,
and a high-energy absorption edge. By comparing the measured optical
conductivity to first-principles calculations and the optical response of other
nickelates, we find that Nd$_{4}$Ni$_{3}$O$_{8}$ features evident charge-stripe
fluctuations. The $\beta$ band is attributed to electronic transitions between
the gapped Ni-$d_{x^2-y^2}$ bands due to fluctuating charge stripes, while the
high-frequency absorption edge corresponds to the onset of transitions
involving other high-energy bands. Furthermore, an analysis of the
temperature-dependent optical spectral weight reveals a $T^{2}$ law, which is
likely to originate from strong correlation effects.
