Hi all,

How different are the iso-astigmatism plots between degressive and progressives?

And given that the reference power in degressives is the combined near add - is there more control over the lens during casting and cutting - so that having a shallower or deeper frame is irrelevant?

I guess, my question in another form is: all else equal, if there are two frames (one deeper, one shallower) - would there be power difference at datum (usually the point of intermediate distance) and bottom (reading distance) on both frames?

I currently have a px who is struggling with a deeper frame on the same Rx (different design) than her older, shallower ones.

Any ideas?