They have a mounting for a lens clip where you can put custom prescription lenses. When I bought my Airs they came with a lens frame and opticians' blanks - basically reference lenses that show where the eyeline is - which you can take to an optician for them to use.

I got my first set done at a high street optician - Specsavers in the UK - and they were able to do it based on some lens blanks they already had that were close enough in size to what XReal sent. Took less than a week to let me know they were done.

But also there's a partner that XReal advertise on their site to do the job. When I got a new prescription recently I gave them a try, and they results are just as good. A little better, actually, but I can't tell what's them and what's having a newer prescription.

I should point out that my lenses mainly correct astigmatism, so any models which only have myopia correction wouldn't be any good to me at all. It's got to be custom lenses for me, and it's fine.