I use a Tusa Liberator mask (and very old Sherwood mask) both with different prescription lens for each eye. These are a two-lens design mask unlike the CrystalVu which has a large single front lens (+ side windows). Each lens cost me about ?20 on top of the cost of the mask - though its possible to get cheaper somewhere, and is pretty easy to replace the original glass lenses.
Assuming that both your eyes needs the same correction factor, then scubapro might make make a tempered lens for your mask. It is more likely (if you'd prefer to stick with scubapro) that their "Freedom" mask might be a more likely candidate.
Here's a link to some of their stuff: <a href="http://www.scubapro.co.uk/pdfs/Page70-73.pdf" >http://www.scubapro.co.uk/pdfs/Page70-73.pdf</a>
Regarding the purge valve, I generally live with a bit of water when I don't quite clear my mask completely..
I have a cheaper mask on the rare occasion Im wearing soft disposible contact lenses, but you could loose these whilst doing mask clearing drills - and mentioned in some schools of thought that contact lenses and diving may be bad for your eyes - probably foreign bodies (and grit, etc) sticking to the contact lens which may lead to possible risk of infection.
Im not advocating any particular brand, just prefer to be able to see a little more than when not wearing my mask. You never know, someone might make correcting lenses for your mask.
good luck in your search.
Andy
Hi can anyone help?
I'm looking for:
a) a mask with wide field of view, like the 'multi window' type, e.g. scubapro 'CystalVu'
b) purge valve,
c) one that I can fit corrective/presciption lenses to.
Does anyone know any good contacts to meet a+b+c above at all?
Si