Since both topics were old, 2009 and again in 2012, I decided to give you some information on my experience just recently, 2013, regarding prescription dive masks.
I had my eyes checked in February, 2013, and was told my prescription had changed drastically. As I was getting ready for my Turks and Caicos dive trip, I realized that I had forgotten to get an updated prescription for my dive masks, Atomic Sub-frame (I love these masks). I have always used Prescription Dive Mask (PDM) out of California for my dive masks but after reading some negatives on this forum in 2009, I decided to go with RXSportoptics.com, which came highly recommended. I assumed that RX Sports Optics could update my mask with the new prescription so I overnighted the mask, at a cost of ($75), to Dr. Maggiore. Unfortunately, he cannot do that. He can only do new masks. Because of time constraints (my own fault), I had to purchase one of his masks, Tusa Liberator Plus, which he promptly put in the updated prescription and overnighted to me (at $43.50). I have no idea if this mask will work for me nor do I have any idea how well the placement of the bifocal will be since I could not place dots and bifocal line on the mask for underwater photography. I called PDM (http://prescriptiondivemasks.com
), and asked them if they could have updated my mask. They explained that they have different mask plates for a variety of the most popular masks, of which Atomic Sub-frame was one, and replace your old mask plate with a new one which has the new prescription lenses.
For this costly mistake, it was $$424.80, which included overnight shipping, the bifocal lenses, and a new mask.
So my tip, if you need an updated prescription in your dive mask:
1. Call first, and ask if they can update your prescription in your dive mask. Be sure to mention that you have an older prescription lenses in the mask.
2. If they can, make sure they have the right mask plate that fits your dive mask.
3. Let them know if you are an underwater photographer so they can instruct you as to the correct bifocal placement
3. Most important, DON"T wait to the last minute to do this. It will be a considerably less cost to you.
I plan to send my two Atomic masks to PDM when I return to have updated prescription lenses put in. And, I hope this helps.