15mm Stellarvue is identical to the 14mm ES 82, field curvature and all, as noted above.
All marketing. They slap on the "15mm" on the side and everybody assumes it is actually 15mm, when it is really 14mm.
I doubt this as JOC won't sell eyepieces to any US brand other than ES since 2012.
It is likely KUO like the WP Meade UWA, who also make the UWAN/PWA.
But I can't confirm, and they could be a whole new OEM same as the luminos perhaps, rather than the initial SV82 which I am pretty sure was the UWAN.
In the case of the old JOC days, the axiom LX 15mm was probably the same as the 14mm UWA.
For some reason, uncle Al seems to have a monopoly on 13-16mm compact 82s that perform well in fast scopes as the 16 UWAN was the weak link in that line as well, but I don't remember ever trying the 16, or scrutinizing the 15mm axiom LX vs the 14 Meade or ES. My bad experience with the 14 Meade put a bad taste in my mouth so I stuck to the big series 4000 version, and never gave the 5000s and axiom LX much thought even when I had access to try them whenever I wanted . I did sell a lot of axiom LXs though, and owned the 23mm for a while and was impressed with it. It was definitely one of the better ones, as the 24uwa/es82 is, and likely the exact same optics.
Unfortunately EP focal lengths are rarely exactly accurate and in the case of the axioms they were obviously paying homage to the original 23mm axiom and 24mm was close enough to call a 23.
And the 31 was the same as the 30uwa/82, but obviously marketed as a 31 nagler alternative.
Astromania now sells a 32mm, but I suspect it is a 31mm Luminos.
I doubt Vic Maris will reveal who his OEM is 