Yeah I had the exact same response.

There needs to be a 'permanently' in there somewhere.

  "Through further clinical trials, it is trying to determine how long the effect lasts after the user wears the device, and how many days in total the user must wear the device to achieve a permanent correction for nearsightedness."

Permanently wouldn't be very accurate either.

> how many days in total the user must wear the device to achieve a permanent correction

Sounds like they think it will be permanent, since they use the world permanent in that exact snippet you quoted.

Ok, we've edited the title above to make it clear that it's a treatment device.