I don’t know when it was but I once read that the Carl Zeiss Company was one of the first purchasers of the Univac Computer.
Before that, they would hire a large number of math teachers to do the complex calculations necessary for lens design.
One of my favorite books is “Surely You’re Joking Mr. Feynman”, and in it Richard Feynman talks about how they did the calculations for the Atomic Bomb...rooms of teams of people with colored index cards that they would perform various things, stack them in a certain order, another team would pick them up, bring them to another room, and people would do more calculations.
I found it fascinating...