This is the most honest answer I can give and if it sounds a bit bleak, sorry.
From the other side of the curtain I can tell you that no matter how many times you get the answer "we treat all applicants equal" from official communications channels, the hard truth is different and that should be obvious when looking at match rate statistics for IMGs. And regardless of ACGME accreditation and not "technically" being an IMG or whatever - if you graduate from a medical school that is not in the US you are considered an IMG to an Ophthalmology program director. Sure, Canada is better than France or India, but you're still an IMG. Beware of people who are accustomed to Internal Medicine or other residency applications because Ophthalmology is not at all the same process.
I think it helps to understand the perspective of the other side, so here's how the application process works at most institutions for Ophthalmology that I know of:
1. Program Director receives an enormous amount of applications from all over the world.
2. Gather all the IMGs as a group and then send them all rejection letters.
3. This step used to be to repeat #2 for DO applicants but this is thankfully changing at many institutions and DOs have a way better chance of matching into MD Ophtho programs than in the past.
4. Screen out all the US MDs below the whatever the lowest Step score the institution has decided to accept. One published survey said that only 30% of programs had a USMLE cut-off, but I am highly skeptical of that claim.
5. Review the remaining applications in more detail to decide the invitation list.
Honestly, most successful applicants to Ophthalmology are in the boat where they are stressing about the details that separate them from the crowd AFTER point #5 here. And I just want to say that although this process may seem unfair or biased it's really just pragmatic. When you get 600 applications for 3 positions every single year that you have to sort through after your week of a full clinic and OR schedule... you're going to find a way to streamline that process. You can cut out much more than half of that work pretty much instantly in steps 2, 3, & 4 above. So that's what happens. At the end of the day a program interviews only 10-20% of applications it receives and you have to make that 80-90% culling somehow.
The most likely situation in which this typically goes any differently for an applicant is if they have a personal connection to a program. I know at least a handful of people personally that only received interviews at 1-3 programs and still matched. They got interviews only at programs where they knew people in the program/administration, had done away rotations and made a very favorable impression, and at their home programs. And they matched, because a known entity with good work ethic who is intelligent and just bad at standardized tests is still a great Ophthalmology applicant and a better gamble than the 260 step score guy that seemed a little cocky on interview day.
So despite having dual-citizenship, in a lot of institutions your application is likely not going to be looked at long enough for a program director to even see it. There is a higher chance for you than other IMGs, for sure. But not really close to the chance that a US graduate has at a fair look.
If I was in your shoes, knowing what I know, this would be my plan:
1. Match into Ophthalmology in Canada. Good standard of living, nice people up north, and salaries typically a little higher for comprehensive Ophthalmologists. I know Tim Horton's is going through a rough patch right now but you've got that national treasure too.
Alternatively for the US path:
1. Blow the Step exams out of the water, score as high as you absolutely can.
2. Everything else on your resume should be stellar as well (research, volunteer activities, etc)
2. Do an intern year in the USA or you're making this even harder on yourself, this might be out of order on the list.
4. Do away rotations at a number of low-tier Ophthalmology programs in the US and be absolutely stellar and endear yourself to the people at those programs.
5. While at those programs, try to obtain some sources for good letters of recommendation.
6. Get your application in early.
7. Reach out directly via email or phone to each program where you apply saying that you wanted to let them know ahead of time that although you went to medical school in Canada, you are a US citizen as well and do not require a visa.
At least that's what I'd do. A match is possible, but not probable given the match statistics. You'll have to do everything possible to skew the odds in your favor. Good luck!