Yes! I am not blind or visually impaired but actually grew out the entire accessibility consultant practice at my old web consultancy along side one of my front end developers. There's a pretty decent market for it now ever since Domino's and Target lost their respective cases. Lots of the jobs are available in the government and education sectors. I used to get a few recruiters every year looking for accessibility consultants.

The Perkins School for the Blind actually runs an entire accessibility digital agency ($1)

Edit: It's actually still a bit of my job now. I'm a B2B product manager and a number of our clients have legal requirements so I still do some consulting on our own internal product to hit WCAG 2.0 AA.

I know people who are, but they tend to focus on accessibility for various disabilities, not just visual impairment. Most start out by being hired by one company and then having recognition. Because it's generally contract work, it's a bit unstable unless you have other forms of income.

You could take the courses on web accessibility from Deque, then at least having some credentials.

That's what I do, I'm an accessibility specialist. I work primarily part-time for one company, do a lot of paid testing work work, plus speak at various tech firms and events about the importance of inclusivity and accessibility. While a good majority of what I do stems around blind and VI accessible tech, I make sure I drive home the ideals of empathetic design for people with all manner of disabilities and other access barriers when using a product, site, or app.

I work for a QA testing organisation, and I can tell you, their is such a job, however as others have said, it's not just blindness, but all manner of disabilities.
I also help test apps and websites for a local college, as their are students and staff with disabilities.
There has been a big jump on the focus of accessibility since 2015 or 2016, and it doesn't show any sign of stopping. The college I work for has passed a new policy that all software must be at least partly accessible, to insure that everyone who needs to use it can do so. Be it staff or students.

My university has a similar job. It's a person who helps get students what they require accesibility wise for school.

I work at the dutch accessibility foundation and i can tell you. There is such a job.