Prescription dive mask measurements

[pardsie]

Prescription dive mask seems to be very popular and also highly recommended on this forum. My question is this: after e-mailing them a few questions regarding mask choices they obviously can do most any mask. I did inquire as to how a prescription might differ between above and below water. They indicated the script is the same however they do need the distance between your eyes and the glass of the mask chosen. My question is who does the measuring. Should you use your local LDS. If you do you would probably have to purchase a mask they sell. What measurements are required other than your prescription.
TIA
Pardsie

 

[Teamcasa]

I had my wife mark mine but any optometrist will mark it up for you.

 

[Charlie99]

Although they correct the prescription for the larger distance between the eye and the lens than in a normal pair of eyeglasses, in my case at least, they estimated that distance without any input from me.

What I supplied was a prescription and a mask marked to show the center of my eyes when looking forward, and a line where I wanted to end the distance prescription and go to flat glass (my near prescription is negligible). I think I also supplied interpupilary distance (IPD) since that wasn't on the prescription sheet from the opthalmologist. (It did indeed match up with my estimated positions for the center of the eyes.)

 

[InTheBlue]

Pupilliary Distance

You will need a very simple measurement, to ensure you get the very best results from your mask or goggles. This is the measurement of the distance between your pupils, ( your PD ) when looking straight ahead. An accurate PD measurement enables us to position the optical centres of the lenses exactly in-line with the centres of your eyes, to ensure maximum visual comfort. You can either use a mirror to take the PD measurement yourself, or get a friend to assist you. The easiest way is to take a piece of firm card and hold it below your eyes and then make a pencil mark directly in line with each pupil and measure the distance between the two marks in millimetres.( mm. ) A typical adult measurement will be between 58 and 70mm.