  The optical conductivity contains relevant information on the properties of
correlated electron systems. In infinite dimensions, where dynamical mean field
theory becomes exact, vertex corrections can be neglected and the conductivity
computed from particle-hole bubbles. An interesting question concerns the
nature and effect of the most relevant vertex corrections in finite-dimensional
systems. A recent numerical study showed that the dominant vertex correction
near an ordering instability with wave vector {\pi} comes from a vertical
ladder, analogous to the Maki-Thompson diagram. Since the RPA version of this
ladder diagram, dubbed {\pi}-ton, can be easily evaluated, this suggests a
simple procedure for incorporating antiferromagnetic or charge density wave
fluctuations into dynamical mean field estimates of the optical conductivity
and related susceptibilities. We implement this procedure for the half-filled
Hubbard model, considering the {\pi}-ton and a double-ladder extension of the
{\pi}-ton, and reveal the spectral signatures of these vertex corrections.
