on Abbot Street in Gastown is an authorized Oliver Peoples dealer. I got my prescription glasses there. If you do go there, see Elaine. She's super helpful, friendly and very cute too!
Overall, they're very knowledgeable of their products and offer excellent after-sales support. I'd definitely go back to them.
Eyes on Twelfth is also an Oliver Peoples authorized dealer however, I have no experience there.
Can't help you on the Cutler & Gross as I'm not familiar with that particular designer/brand.