RGP lenses Menicon V the others

Hi,

As far as I can see, "state of the art" RGP technology that optometrists
are used to is...

Bausch and Lomb Maxim Ultra, ML210

Meanwhile, I have seen on the Internet Bausch and Lomb XO lenses which
on first inspection seem to have a much higher DK value, but on closer
inspection it seems just to be a difference in measuring standard.

I have also seen Menicon Z lenses which seem to be on a whole different
world as far as DK values are concerned.

Yes, I know that DK value isn't everything, but would it be worth
pursuing the Menicon Z route? (even if I do force my optometrist to
explore technology he has never heard of before).

My prescription is about -15. On past experience (with old Maxim ML92
lenses) I do get "tired eyes" at the end of the day which seems to
indicate a need for a higher DK value.

Also, I love the idea of occasionally being able to sleep with the
lenses in (when I am away for the weekend etc.)

So, is it worth hounding down some Menicon lenses, or should I just
settle for ML210's