BMC did a leaflet thingy on working with the visually-impaired in a climbing setting:
https://www.thebmc.co.uk/Download.aspx?id=1456GB Paraclimbing Team's got several visually-impaired team members at the mo, so they or anyone working with them might be well worth consulting.
Also, the Power Company podcast and the Enormocast both did recent interviews with Justin Salas, a visually-impaired beast, which might be of interest as an example of one person's experiences.
As someone with a different disability, I would add: don't overlook the importance of asking the individual person/people you're working with what they need and what's helpful for them. There's never a "one size fits all".
If they're new to climbing, then obviously it's going to be helpful if you know what sort of things work for other visually-impaired climbers and the various adaptations that have been developed. If they're not, then they probably already know what works for them and can tell you.
