  Geometric optics effectively describes the propagation of electromagnetic
waves when the wavelength is much smaller than the characteristic length scale
of the medium, making wave phenomena like diffraction negligible. As a result,
light propagation in a vacuum is typically modeled by rays that follow null
geodesics. However, general relativity predicts that polarization-dependent
deviations from these geodesics occur in an inhomogeneous gravitational field.
In this article, we evaluate the corrections for the deflection and emission of
light by a massive gravitating body. Additionally, we derive the scaling
behavior of the physical parameters characterizing the trajectories. The
calculations are performed in the leading order in frequency. We use these
results to assess the significance of the birefringence effect in various
astrophysical observations. We find that the effect cannot be measured with
current instruments but may be detectable in the near future.
