My neuro-opthalmologist gave me stick-on prisms. He realized my eyes change and gave me TWO different strengths -- one for early in the day and one for later when my eyes are weaker. I absolutely LOVE my stick-ons! Of course they don't weigh anything. I am careful with them, using soap and water to clean -- as you would also have to be with plastic lenses. Here is the link:

http://www.fresnel-prism.com/product...ess-on-optics/

My doc attached them to readers for me -- I can DRIVE and SEE when I'm walking -- and I just feel NORMAL, now! The readers were about $20 each at Walgreens and I think the prisms cost about $40 per lens? (Insurance may take care of some or all of this.) I'd recommend GOOD quality readers because you are gonna wear these things ALL the time!!