To practice in Canada, as already stated, you will need to pass the Canadian Boards as well as whatever provincial exam is required. The training of Waterloo students gears them towards the Canadian Boards, thus they do well. The Canadian Boards exams are VERY poor quality with dated concepts and pharmacology. Waterloo is always so proud of the pass rates of its students, but if you receive you education in most US schools you will get much more excellent clinical experience. As an example, a Canadian educated OD doing her residency at my school in the US only saw ONE case of diabetic retinopathy before she graduated from OD school. Third year students at my school (including myself) were always teaching her pathology.
My point is, if you are educated in the US don't be intimidated by the Canadian Boards...you will pass if you study and you will find yourself very well prepared for delivering eye health care to your patients.
JP