You have to take out loans from Canadian banks. US schools won't generally give you scholarships etc. if you're international. Even if they do, it'll be a tiny amount. I'd stick to cheaper Optometry schools if I were you.
Starting optometry school in august 2019 Canadian applicant here. From what I'e been told you can apply for student lines of credit, you can use your provincial student loans, if you have high grades you can get scholarships and you can take out a home equity loan..
You pretty much need this to afford school in the states.
International students can't apply for most scholarships and the ones you'll get will be a tiny amount. Provincial loans also aren't enough (~8K/year if you're from Ontario, I think more if you're from Alberta).
Yeah its about 60k total from alberta student loans, I didn't use my loans for undergrad so I might be eligible for more. And in terms of scholarships I got offered $40k, which isn't a lot but it's still an amount that helps. Some schools offer half tuition and up to 60-80K for all 4 years that Canadians are eligible for too. But yeah its do able but its very expensive.