"This paper analyzes these corrections scientifically and demonstrates that the illusions they are supposed to correct are either non-existent or so small as to be imperceptible."
So the paper claims to demonstrate that there are no optical corrections that work, not that "There are no optical corrections".
This is supposed to be science, guys.
It has always struck me as unlikely. We build buildings all the time with straight lines, and nobody looks at them and thinks "my house sags".