  We discuss the contribution of axion-like excitations (ALE) to the vacuum
birrefringence in the limit $m_A \gtrsim \omega$, where $m_A$ is the mass of
the excitation and $\omega$ the energy of test photons interacting with an
external (intense) magnetic field. The relevance of this term with respect to
the QED contribution depends on the ratio $g_A/m_A$ and, from present bounds on
the mass and the coupling constant $g_A$, we find that in the present low
energy regime, it ranges from $10^{-14}$ to $10^2$ suggesting an interesting
alternative to explore.
