Is it possible to replace the Lens with prescription lens ?

Yes My optometrist replaced the demo lens w my new bifocal prescription As a retired Optometrist I am confident that you will be happy w results particularly utilizing polycarbonate rx lenses

if I get the frames lenses, how do I Get my prescription added?

That's what I did. I went to My Eye Dr and had them put in transition lenses. They work great! Saved 100s Replacing my older Silhouette frames. The store is no longer carrying that type of frame, only the trendy, bulky frames. I thought I'd try this out and it worked great.

Sirven para usar como armadura con tu graduación personal ?

Sí, yo los uso para mis lentes de medida y son muy livianos

What size are these ?

They are listed at 52mm. In addition to my other problems I have a giant, bucket-sized head so I think these would work well for all except those with a narrow face. Might be able to get your optician to get smaller lenses.