If characters in a story have a disability the question should be "What is the DM/Author trying to say, and how does this character add to the world they are portraying?" The plague of diegetic essentialism etc.

Had a session last night, where my player where asking this question, and posted this post as a response on the screen, and it started in, how could we do a magic chair into, let's make an exo-squeleton. I come there to say,

That as a DM I have stollen your stuff and added it to my campaign

Was there a reason for them to be blind?