It wasn't scarlet fever that blinded Mary Ingalls after all. It was the much less kid-friendly viral meningoencephalitis.
But whatever it was, it still makes me glad that I live in the age of modern medicine. People still get viral meningoencephalitis, but most of them don't go blind from it. Of course, if they do, it turns out that the college for the blind that Mary went to in Vinton, Iowa still exists. It's called the Iowa Braille and Sight Saving School these days, and it's got a Mary Ingalls Society to raise funds to preserve the school's history.