Did it for myself. Ordered online. Best glasses yet (I think mainly thanks to a my very patient optometrist.)

I measured by taking a picture of my face with a credit card for reference and measuring the pixels with the measuring tool in GIMP. (These were the actual instructions on the website I ordered my glasses from.)

Also worth mentioning I paid $40 ordering them online, in the article it says he paid $280!

May I ask you where you ordered them?

Edit: Just found out they ship worldwide for €3.

https://www.glasses24.com/customer-support/shipping-and-deli...

I was amazed because until a friend told me about this site, I've been paying hundreds of euros just for the frames! At such a low cost, I could even order slight variations on the strength.

They have a lot of options for better lens material, have it darken in sunlight, anti glare coating etc, but I just got the cheapest one and it was fine.

I found that it's easier to do it yourself than have someone else do it -- my wife and I measured mine, hers was off from mine by 6mm (2mm on one side, 4mm on the other, I have no idea how she was nearly half a centimeter off, maybe my eye moved), I ended up going to an optician a few months later, and my measurement was exactly the same as what they measured with some device.

Don't see how you can possibly do it for anyone else, using the mirror method, without getting it very wrong.