I am quite nearsighted, so I depend on having my prescription eyeglasses at all times. Consequently, I like to have several back-up pairs handy. After shopping around, I found a very inexpensive online source, and I was quite pleased with the price and quality of the glasses I ordered.
I paid $110 for one pair of single vision lenses with high index refraction, for a thinner lens with my strong prescription, with a nice rimless metal frame. The price is even less with an order of more than one pair, which can have different Rx's and frames. For example, three pair with regular lenses are $53 per pair. All frames are about the same price, I believe.
Their price for progressive lenses with high index adds $220 per pair (but the price for regular progressives is quite reasonable), so I'm still looking for an inexpensive source for those.
If you depend on your glasses, its worth having spares on hand, in your BOB, etc.
If anyone knows a good source for high index progressives, please let me know.
Usual disclaimers apply.
Jeff
http://myeyeglasses.net/products.htm