So I just came across this story in google news:
https://petapixel.com/2019/07/05/goo...tical-problem/

So it looks like they've solved the issue of spherical and astigmatic aberrations in biaspheric SV surfaces to a 1 billionth of a percent accuracy.

Now with not having access to the full article, I don't know if it solves the issue for all spherical biaspheric lenses or includes lenses that all also astigmatic (assuming they even cover in this the article as these are optical physicists)

I don't understand the math of progressive lenses enough to know if this can solution can be extended to the distortion issues of progressive lenses but this looks like an exciting development.