Don't know much about history, don't know much biology ...
In case you decide to go a different route from glasses in Mexico, a couple suggestions:
1. Wal-Mart:
As much as I hesitate to direct even more business toward that store, I feel like I need to mention that their optical shops provide exams for about 60 bucks. I just got one a little over a month ago (my first with them) and I was happy with the exam. That said, I was not happy with the customer service provided by the optical technician. Long story short, when I asked for my pupillary distance (PD) measurement, she balked, refused to give it, and started quoting Arizona law against giving me this measurement. I think that was complete bull crap. She did it because she knows that a PD measurement is what's needed to order glasses online, and if she gave it to me, I would not buy glasses from their shop. I eventually got the PD measurement, but it soured me on using them in the future. But like everything else at Walmart, it's cheap if that's important.
2. Zenni Optical:
Ditto on Zenni with a footnote. I've been ordering my glasses from Zenni for over 5 years. Their system, prices, and results are good. However, in my last two orders with them (a couple of years apart), they made the same strange mistake both times. Because their glasses with progressive lenses cost around $50 (instead of the typical $300), I ordered two pairs of the same glasses at the same time. Each time they made one pair correctly and one pair incorrectly. In fact, I'm in the middle of getting the second pair replaced again now from my most recent order. It's still a mystery to me how they manage to do that. That annoyance aside, I recommend them.
Tom