Certain courses throughout the first 3 years of Optometry school. Depends all on you. The hardest part from my experience back when I was in school, was the politics of the school and from what I observed. Politics in your clinical rotations as a third year and fourth. Generally speaking.
You have to go thru the program and experience it as everyone else does.
If you are good or not, no one tries to throw you out, but they can make your life VERY difficult. I know politics is part of life in everything.
My 2 cents.