For those who are near sighted, I made my own lenses by taking an old set of glasses i had, removed the lenses and ground them to size on a bench grinder. First I traced the outline of the lens size from the supplied lens holder on a piece of paper, cut them out, then used double sided tape and put the templates on my spare lenses before grinding. My lens are plastic as most are today, also transitional. After grinding the lenses, slowly, to size, I affixed them to the frames and used a few drops of Superglue to hold them in place. Works great! I like them much better than my contacts because my contacts are monovision and I didn’t get the clarity. I really love the BT 300s.