Blindsight refers to the residual ability to make visual responses when a patient is subjectively blind in certain regions of his or her visual field. This means, paradoxically, that patients with this condition are making visual responses to stimuli they cannot see, that is, to which they are not aware.
Refer back to Chapter 4 and the story of Patient T.N. a medical doctor, who had two strokes less than a month apart in the early 2000s. The strokes caused permanent and complete blindness (Buetti et al., 2013). He has no conscious awareness of seeing yet he can use his vision. On the next tab see a video of his navigating a hallway strewn with obstacles that he had no awareness that they are there.