The research is as impressive as the acquisitions,, as usual!
My pet theory on AR
sestertii is that, despite their seeming utility as a "half-ish-y" day's pay, perhaps the reality is similar to ours: by the age that you can readily put a half-day of pay into a tiny coin, you can barely see it. Apparently, according to the late
numismatist & ophthalmologist Dr. Jay Galst, the age of onset for nearsightedness has not changed nearly as much as life-expectancy. So, perhaps 45 to 55 year old
Romans found them just as hard to read as Borghesi.