Blindsight is a phenomenon which occurs due to damage within an individual’s primary visual cortex. Due to this, the individual loses conscious vision and is unable to see, becoming legally blind. However, with the eyes themselves still fully functional, the individual can still tell where objects are, though they claim they cannot see it. Studies in monkeys have been done that suggests this effect, and experiments have been performed with human candidates as well. It is one of the most bizarre phenomenons that occurs within the human body due to brain injury.

Additional Resources/Studies:

Signal Detection Analysis of Blindsight in Monkeys

Seeing Without Knowing It

Seeing Without Seeing?

First-Order Consciousness in Blindsight

Blindsight Case Study

Blindight: How the Brain Sees What You Do Not See