I'm assuming you mean Greater Toronto Area.
I shadowed in an office at on Sheppard in between Yonge and Bayview called Eyes on Sheppard.
Unbelievable place, amazing people work there. They get really busy during the summer so maybe you tried them already and they were full...?
There is another place north that I never ended up shadowing at but I had the option to...it's off of Centre street around the Promenade between Bathurst and Dufferin.
Honestly your best bet in my opinion is find someone you know who goes to an optometrist in the area, and if they have a good repore with them, get them to ask for you.