Scanning-based image formation fundamentally differs from its classical lens-based counterpart. Therefore, established classical performance evaluation methods fail to determine the theoretical limitations of scanning-based optical systems. We developed a simulation framework and a novel performance evaluation process to evaluate the achievable contrast in scanning systems. Applying these tools, we conducted a study determining the resolution limits of different Lissajous scanning approaches. For the first time, we identify and quantify spatial and directional dependencies of the optical contrast and demonstrate their significant impact on the perceived image quality. We prove that the observed effects are more pronounced for Lissajous systems with high ratios of the two scanning frequencies. The presented method and results can lay the foundation for a more sophisticated application-specific design of next-generation scanning systems.