If they include world-wide users, I can see 35 million users being a reasonable statistic. If we're talking about just the USA though, depending on the definition of "blind and low-vision," I found figures between 8 million [1] and 22.5 million [2].
[1]- https://nfb.org/blindness-statistics [2] - http://www.afb.org/info/blindness-statistics/adults/facts-an...