As he moved through the large world of the server he would repeatedly encounter people who asked him if he was a seer (Sehender, in German). For a while he thought that this is some trait or role that you can have in the game.
Turned out, though, that being a seer means that your eyes work as they do for most people in the world. And that was less common on this server to have than not. Many people with impared vision played there, using screen readers.
Hence, instead of talking of blind people, this place shifted to talking about seers, while visual impairment was normal :) And I do believe that this majority of players had a much better visual image of the world they're playing in than those staring at a wall of ASCII.
Unfortunately, I don't know what server that was. But I assume that MUDs gain some of their continued popularity from there.
[1] https://en.wikipedia.org/wiki/MUD A MUD (/mʌd/; originally multi-user dungeon, with later variants multi-user dimension and multi-user domain)[1][2] is a multiplayer real-time virtual world, usually text-based. MUDs combine elements of role-playing games, hack and slash, player versus player, interactive fiction, and online chat. Players can read or view descriptions of rooms, objects, other players, non-player characters, and actions performed in the virtual world. Players typically interact with each other and the world by typing commands that resemble a natural language.