I'd vote for anti-VEGF (growth factor) drugs. They're used for macular degeneration and diabetes-related blindness, a number of cancers... and they're very expensive! A year's worth of monthly injections for macular degeneration (12 doses) was close to $30k a year five years ago; now it's down to a bit less than half of that price.

The red-green test (binocular balancing) does work on anomalous trichromats, i.e. most of the people who are colourblind or colour deficient. Just because you can't distinguish between red and green doesn't change the way the wavelengths focus. (We have to adjust our questions to refer to the right or left side, rather than the red or green, but that's about it.)
Very few people are missing a particular colour of cones; rather, the light-sensitive pigment is altered by genetics to be most sensitive to a different/"wrong" wavelength. So your red-green colour deficient people usually have their 'green' cones more sensitive to red instead of green (or vice versa). That doesn't mean that they don't see green, they're just less sensitive to it than they are to red; the photopigments are still activated by wavelengths other than the one they're most sensitive to.
For more info, look up the spectral sensitivity functions for the various photopigments; you can imagine how shifting the sensitivity of any of the curves will affect things, but it will in no way prevent normal colours from being visible.
(I'm an optometrist. And yes, it's spelled "colour" here.)

Doesn't this mean that anyone in China who speaks, say, English or Russian could get around the censorship just by searching Bing in their other language? And I suppose this also prevents Chinese people from using a proxy to search Bing, if anything in simplified Chinese is being censored regardless of IP location?

Wouldn't it be great to have a free wireless network available virtually nationwide, regardless of filtering, for the simple purpose of online connected devices? Alarm clocks that gather local news and weather, refrigerators that order milk for you when you run out, an oven that preheats when you signal it from your car on the way home... none of these tasks need tons of bandwidth, nor do they depend on having uncensored access. I think this free wireless might take these sorts of things from the realm of science fiction, or at least hardcore geeks, to the hands of the masses.