There are basically two kinds - RX and in frame.
In frame a re great - top quality prescription lenses in tint. The downside is if you want clear / low sun / high sun, you need 3 pair glasses at prescription cost.
I currently use Rudy Project Rydon, with Rx inserts. Pretty normal cycling sunshades that have a clip in set of prescription lenses behind the sun lenses, so you can swap to whatever conditions require without needing multiple prescription lenses. They are slightly more prone to fogging (especially on cold morning at traffic lights, but they clear quickly). There can also be limitations on prescription in some Rx inserts, but my catastrophically big bifocal prescription can be accommodated in the Rydon's though clearance between eyelashes and lens is fag paper (My wife suggested my idea of trimming eyelashes was a bad idea btw, not sure why...)
I've tried various makes of Rx glasses over the years, and can honestly say the RPs are the best I've ever had.