If you go to an optometrist, he will hand you a prescription, which will say something like 1.75. If the prescription is identical for both eyes, all you need are glasses with this degree of magnification.
If you take this prescription to the store in the Mall, they will stick you for around $40 for the lens and up to $300 or more for the frames. The markup on frames is enormous. They will try to stick you for another $30 for some special scratch free coating and even more for UV protection. This is no more necessary than UV protection is necessary for people with 20-20 vision when they read in the park. UV protection is the opticians equivalent of "special paint glaze protection" and $100 pinstriping jobs car dealers like to stick the saps with.
If you take that same prescription to Walgreen's or Family dollar and buy reading glasses that say "1.75", you will have exactly the same degree of magnification.
I suggest that any corrective glasses that are bought according to a prescription are prescription glasses no matter where you bought them. The only difference is that you pay less, you don't have to wait, and if you lose your glasses, it is no big deal.
If you like fancy frames, check out your local Goodwill/ Salvation Army. Pop out the old lenses and have your optometrist install lenses to fit. That way you can get special titanium designer frames for maybe $5 instead of $300.
Like most medical services, profits are astronomical for glasses. Unlike other medical procedures, you can legally outwit the system. You can use your head or you can be a sucker.
