The eye glasses ping-pong game, between the optometrist and Costco is over. So as to not spend an hour composing the game's end, I'll just say that I'm keeping the two-year-old prescription and glasses.
Your first mistake was using an optometrist. Never ever again for me, nothing but grief. Regardless what they call themselves an optometrist IS NOT an eye doctor. An optometrist is nothing more than an eye glass salesman and their only interest is selling you more and more radically overpriced glasses. Helping you isn't even on the priority list, only helping their bank account.
Make an appointment with a real eye doctor and go see an Ophthalmologist.