Doctors are not allowed to give diagnosis and treatment without seeing the
patient.
It seems that you've already have the general picture. I'd suggest first
looking into options in China (treatment for cataract is pretty much the
same everywhere - surgery). You can also comb databases like medline to
investigate new therapies. Once you nailed down something that is
unavailable in China or better done in the US, then worry about getting your
mom here to see an opthamologist.
