I had a nice pair of Gucci sunglass that I could not use because my vision is not as good as it used to be (due to age).
So I decided to make my own and save $300 usd or more.
I kept my old lenses from last time I updated my glasses.
Step 1: Align Your Lenses - Prescription Sun Glasses - Make Your Own
Use scotch tape to experiment and find the right location of the lenses for you.
Once I found the right location, I used liquid electric tape to glue the lenses to the sun glasses (only added a bit at each corner of the lenses)
I recommend using clear silicone caulking for a better look. I already had the liquid electric tape, so I used that.
Step 2: Finished - Prescription Sun Glasses - Make Your Own
Finished project. The four black dots are somewhat visible from the front but I don't mind that.
Enjoy those old glasses again. I have an old pair of Ray-ban Aviators waiting to be upgraded.