In order to confirm the theoretical results for the modulation transfer of an optical system with varying amounts of astigmatism it is first necessary to devise a method for introducing the required amount of astigmatism. This was very simply achieved using a low-power cylindrical spectacle lens. The modulation transfer for lines oriented parallel, perpendicular and at 45° to the tangential plane was measured using the interferometer described in a previous paper and good agreement was found between theory and experiment.
ANTHONY J. MONTGOMERY, "Measurement of Modulation Transfer Functions in the Presence of Astigmatism," J. Opt. Soc. Am. 54, 519-519 (1964)