My mother did not want me to have glasses as kid, because glasses damage your eyes. It is a scam of the optometrists. They sell you glasses to damage your eyes, so they can sell you even more glasses later.

So when I became nearsighted, I did not wear glasses until I was almost an adult.

The myopia remained rather stable with -1 to -1.5 D. Which fits the distance of the computer screen. It was very unhealthy that I spend 12 h a day programming thinking I was a professional teenage software engineer.

But I got really bad astigmatism with -3.4 D according to an aberrometer.

Perhaps myopia turns into astigmatism if you squint too much?