About 253 million people (i.e. more than 3% of world population) are blind or visually impaired

According to the World Health Organization, 253 million people, more than 3 percent of the world’s population, are blind or visually impaired.

https://www.bloomberg.com/news/articles/2018-02-19/a-1-billion-valuation-for-mobileye-founders-latest-venture