[Steve44]

> Opticians will often refuse to disclose pupillary distance, as a way to prevent their customer from purchasing elsewhere

As I understand their logic is that the PD is part of the fitting process for the glasses and not the optical prescription.

[walterbell]

Except that’s not true. PD varies by focal distance (far, near) and is unchanged by any frame.

Perhaps they obtain frame measurements at the same time as they measure PD. But the machine is capable of measuring PD alone.

Try another store/human.

[Steve44]

Over the years I've been to several opticians and they all measure the PD with a special looking ruler as part of the frame fitting measurements.

I don't doubt that it could be measured as part of the optical prescription process but it isn't as far as I've seen. I'm in the UK.

[walterbell]

This is what Lenscrafters (US) uses: http://www.uiwoptometryblog.org/2013/09/accufit/