  Using a multi-plane lensing method that we have developed, we follow the
evolution of light beams as they propagate through inhomogeneous universes. We
use a P3M code to simulate the formation and evolution of large-scale
structure. The resolution of the simulations is increased to sub-Megaparsec
scales by using a Monte Carlo method to locate galaxies inside the
computational volume according to the underlying particle distribution.
  We consider cold dark matter models normalized to COBE, and perform a large
parameter survey by varying the cosmological parameters Omega_0, lambda_0, H_0,
and n (the tilt of the primordial power spectrum).
