[starpilot]

That is illegal in the US; the FTC entitles you to a copy of your prescription [1]. This doesn't include your pupillary distance, but shops will tell you whether or not they'll give PD as well. Some places I called offered to measure mine for free as a walk-in, it's pretty quick.

[1] http://www.ftc.gov/bcp/edu/pubs/consumer/alerts/alt143.shtm

[pavel_lishin]

PD seems like something that you could measure at home with a pretty high degree of confidence.

[starpilot]

Many people do. I'd still rather trust an optician using a PD meter though.