Has been -11 for 10 years at least, no changes. I thought most people get more positive as they age?

They saw optometry who gave them new lenses and they see fine now, but it concerns me such a massive change occured so fast. Should I be worried? Do I need to scan their head or something? It just seems so strange.

I know negative 11 is pretty unusual as it is, but 6 diopters seems like a lot.

Edit: dilated fundoscopic examination is completely normal. They are not a diabetic and have no health problems and take no medications other than occasional allergy medications. They don't even take them daily. They are physically fit and perfectly fine otherwise.

literally a totally healthy 32-year-old female went from -11 to -17 (And apparently I was mistaken, the other eye went to -15 in the span of 3 months.