"Turning a blind eye" indicates an act of volition, which is actually in contradiction to the meaning of "blind". If you are mentally "blind" to something, you don't see it, and you therefore don't need to turn from it.
"That's the sound of one hand clapping." - Jim Rockford
To me, a “blind eye” means you see it but CHOOSE not to acknowledge it.
Not that you don’t see it.