Upload & Sell: On
July, 1953, was when the Zuse Z5 was the first commercial mainframe installed in Germany--at Leica headquarters in Wetzlar. ("Zuse Z5," wikipedia.) But Mandler went to Midland, Ontario, in 1954. (Puts, Leica Chronicle, Chapter 18: General Evaluation.) So it may well be that one thing which heavily influenced Mandler's efforts was a friendly competition between Wetzlar, which had a mainframe, and Midland, which presumably still relied upon dozens of clerks with slide rules.
By the 70's, Midland definitely used computer optimization.
I found this passage also relevent:
"Dr. Walter Mandler's chief contribution to the optical engineering was his pioneering works in application of computer aided design in optical engineering. Midland optical department was specialized in the research of retrofocus designs and apochromatic corrections. Mandler employed sophisticated combinations of special glasses in his APO and high-speed designs, and many of these glasses were original Leitz formulas manufactured by Schott or Corning. Mandler was a master in optimizing Double-Gauss designs by means of the computer and a particular method developed by him and explained in his doctoral dissertation."
Nice list of Mandler designed lenses here as well: