Captcha for blind or visually handicapped users

Is your feature request related to a problem? Please describe.

As a blind or visually handicapped user, I would like to be able to register at https://guru3.eventphone.de/register in order to use the services.

Describe the solution you'd like

There is no clear solution. We are looking for a solution that works well for blind users and is not from google.

Describe alternatives you've considered

audio capcha
text quiz capcha with questions like: Type Hans, but not Sandra. Type yellow, not red. Don't type camel, type llama. What's three plus five? What makes 3 times two? What is 9 + four?

Additional context

CAPTCHA https://en.wikipedia.org/wiki/CAPTCHA

Related Tweets:

eventphone / guru3