I am a newbie with high myopia, and what I think my main mistake was measuring from my eye, where as my glasses sit some distance from my eyes. So the cm measurement is more like the contact lens measurement. Subtract half an inch to get to the glass one. Or so I now make sense of this, YMMV.
I bought my 1st normalized based on the cm measurement, a couple of months ago, -6 and -5. I use them everywhere outside home. (I can see 100% with them to distance if I tilt my head back a bit, but as they are, I can see and read the house number across the back yard, maybe 15m away, but not as clearly as with my full prescription.) Now I measured with my new way “to glasses”, it’s like -6.25 and -4.75.
Except, on tennis court… I still use my full, which is -.75 stronger. I need to pull them down my nose not to get a headache. But still, I feel a bit uncoordinated with the normalized. So… I should get a new full description pair.