Matt's right, I have a couple of pairs of the Steward glasses from Simon. I called him, had a chat, e-mailed my prescription to him and ordered 2 pairs, one brown for the sun, one yellow for poor light. They do the job! I didn't even need to see him, although I did need to get my focal point (?) measured by my regular optician. Simon sent the first pair for me to try, and once I'd approved them, he sent me the second pair. Job done.
Will, for info, I have a very poor left eye which I have to close when I shoot - both eyes open to pick up the target, shut left eye once aquired (or as I did on Sunday, close the wrong pigging eye!!). I'm blind as a bat without my specs so I wear them all the time, and had to go to verifocals a few years ago - the new glasses take a little getting used to because they aren't verifocal, so don't try to read in them! I also have a mild astigmatism and am colour blind, although the latter isn't really treatable, no matter what the snake doctors tell you!