Light propagation in Swiss-cheese cosmologies

We study the effect of inhomogeneities on light propagation. The Sachs equations are solved numerically in the Swiss-cheese models with inhomogeneities modeled by the Lemaitre-Tolman solutions. Our results imply that, within the models we study, inhomogeneities may partially mimic the accelerated expansion of the Universe provided the light propagates through regions with lower than the average density. The effect of inhomogeneities is small and full randomization of the photons' trajectories reduces it to an insignificant level.