I have a friend who is blind in one eye. They refused treatment on the other, so I assume that while the risk is very low, it is still somewhat significant. That, or maybe the insurance company won't expose itself to that kind of liability.
Actually it could be that the doctor was acting very ethically "first do no harm" type of thing.
When I went for mine, there was a question if the doctor would appove me, as he didn't like the slightly elevated pressue in my eyes. It was only on further testing they determined I was not a risk for glucoma (more on this in a moment) and proceeded with the procedure.
I remember asking "What if you determine I'm not a good candidate due to this, and I say go ahead anyway?"
He told me he would refuse to perform the procedure, regardless.
I really respected that, and it made me realize I personally wouldn't go anywhere else to have a 2nd opinion, and potentially get it down by someone who would look at my results and say "that's good enough"
It also made me wonder how many people would go and look for someone else to do it, and would find someone willing. yikes.
Re the elevated pressure. I go back to the same practice every year for my eye exam, and it's been pretty much determined that's just normal for my particular pair of eyes. Although they keep a watch out for any change.