How to use your smartphone to check your vision - CNET

This was actually even-handed and reasonable... I'm pleasantly surprised! (Normally the tech media is breathless when it comes to new gizmos)
 
"EyeQue VisionCheck gives you Eyeglass Numbers, which are similar to a prescription, but they don't have a doctor's sign-off. You can use your Eyeglass Numbers to purchase glasses at online retailers."

Is this even legal in the U.S. ?