Myopia measurements

Ok, I probably won’t get a quick answer on this one, but the web has turned up nothing for me.

The international standard for measuring short sightedness is on a scale from 1 - 10. or minus 1 to minus 10. However, you always hear people in Taiwan saying, “I am 750 du” or “1000 du”. Now, that makes no sense to western eye quacks, especially one quack that I met today. This quack told me, when I asked if he knew the difference and how to calculate what my wife would be in NZ measurements, that it is impossible that any country uses any different measurements and he should know because he had travelled the world. (arrogant prick)

Anyway, I think that it may have something to do with decimal points and Taiwanese leaving them out. Like -7.50 would become -750 if we leave out the decimal point. So, next time I see this globe trotter, I want to have all the information that I need.

Is it different. Are the units measured the same but spoken differently. What is the deal?


Your guess is correct, as far as I can see. It is my experience (not professional knowledge) that you just move the decimal point. When I left the (nonexistant, by your optometrist’s definition) United States for Japan, I asked the optometrist to convert my prescription to the more international form. That’s what it looked like he did. (The American form was usually 20/XXX, but I think may be changing.)

you’re right

my prescription is 400 and 600 du

when i buy contacts it says -4.00 and -6.00 on the box