Having a green card or permanent resident status in the US means being eligible for federal loans and adjusting for instate tuition no matter what state. You can think of a green card as being similar to a passport, just one tier below (this is because green card holders dont have certain benefits, for ex. voting during a presidential election).
If you have a green card, you will be considered for federal loan programs and will have no issues when it comes to practicing in the US or being eligible for instate tuition. However, depending on the state, if you are a long term resident of the US certain states will allow you to receive instate tuition even if you are not a citizen or permanent resident.
Since you are Canadian, you will be considered as an international student and I do not believe that you can be eligible for instate tuition at any point during your optometry education.
