Canada has their own exam. They also require 4 years of opththalmology plus one year of internship, which weeds out nearly all American ophthalmologist.
However, I heard of someone that cheated and lied to the Canadian provincial people about his credentials and got a license.
At least, that's what a faculty member told me but he didn't want to say anything for fear for getting murdered by that doctor who cheated. When I was a medical student, I did read of an ophthalmologist in Arizona who got into a dispute with another ophthalmologist and murdered him.