I have been using the Optx brand stick ons for years. They do not stick as well to some glasses as to others, but I think I have only had one lens fall off. If you are putting them on both lenses, I find it easiest to put a post it note on each lens on the outside to be a reference marker so that I can get the tops located at the right height on both lenses. They seam to adhere best if I clean off my hands and glasses with dish soap first to get rid of all skin oils.
My eyesight is good enough that I only need corrective lenses to see the bike computer and GPS, thus non-prescription sunglasses work just fine for me.
Here in USA, there are industrial safety stores in most larger communities. You can often walk in and buy safety glasses. I have bought these in both clear and grey color, less than $15 USD for both pair. They are wrap around glasses, top is uncorrected, lower is a bifocal reading glass insert. This link is to my local safety store, I do not know if they ship out of USA or not.
http://www.conney.com/Product_Eye-Protection-Safety-Glasses-Direct-Safety-Dakota-Readers-Safety-Glasses_50001_10102_-1_227410_11269_11268_11268If the above link did not work, I pasted the description here:
Direct SafetyŽ Dakota Readers Safety Glasses: Grey Frame, 2.0 Diopter Grey Lens
Readers are a combination of reading glasses and safety glasses all-in-one. This versatile safety eyewear offers the flexibility to fit any face shape. One-piece wraparound polycarbonate lens produces full brow protection and a wide, unobstructed field of vision.
They do not have that expensive look that screams "I have too much disposable income", but they work just fine. Different strengths are available.
