A friend of mine works in eyeglasses manufacturing, and I was appalled when he told me the typical markup in this industry. So I went looking for alternatives, and found I could trim the cost by 75%.
Those designer frames your optician changes $140 for might cost him/her $25. It's not unusual for a pair of blended bifocals made with name-brand lenses and designer frames to cost $400 or more, a four-fold or more markup far exceeding most vision insurance program's allowance. How can those of us on very limited incomes beat the high cost of glasses?
The first step is to simply ask your optician for a discount. Keep in mind the markup; they have room to cut you a deal if they know you will comparison shop.
You see, your optician wants you to believe the exam, the prescription, and the glasses selection and delivery are all parts of one transaction, but they aren't. Just because you have a wonderful optician, you aren't obligated to buy your glasses from him. You have every right to obtain a written copy of your prescription and shop around for a better price. Doing so could save you hundreds of dollars.
One place to check is the optical departments of big box stores. For my last pair, I priced WalMart (too high, imho) before ordering from Costco, where I got what I needed at less than half of the price my optician would have charged.