Jo Is One Of My Fav Companions Too - Blog Posts

So like Katy Manning auditioned with contacts and didn't tell anyone how blind she was

But then they made her take them out, presumably because old hard contacts reflected studio lights

and I think, although I'm not 100% sure, that Katy's what really established the trope of the Doctor grabbing a companion's hand to run

and even the Master (gentleman that he was) led Jo by the arm after poor Katy supposedly ran into a tree and knocked herself out

anyway I like to headcanon that Jo was as blind as Katy, keeping her disability a secret so she wouldn't be tossed out of UNIT, but the Doctor just worked with it. He's used to his human friends having various physical limitations, so what's one more or less? He provides a steadying hand when he can, and they manage just fine.

It's part of what the Master finds baffling, although after Jo threw off his mind control he began to understand what the Doctor saw in these creatures despite their obvious deficiencies.