clinically describes patients with bilateral damage to V1, in which they deny being able to see any visual stimulus even though on formal testing they are capable of localizing visual targets accurately
The ability of a person with a lesion in the visual cortex to reach toward or guess at the orientation of objects projected on the part of the visual field that corresponds to this lesion, even though they report that they can see absolutely nothing in that part of their visual field.
A condition in which people who are blind have some spared visual capacities in the absence of any visual awareness. go to glossary index
Some patients who are effectively blind because of brain damage can carry out tasks which appear to be impossible unless they can see the objects. For instance they can reach out and grasp an object, accurately describe whether a stick is vertical or horizontal, or post a letter through a narrow slot . The explanation appears to be that visual information travels along two pathways in the brain. If only one is damaged, a patient may lose the ability to see an object but still be aware of its location and orientation.
Patients with cortical blindness may perceive movement in the peripheral field without being able to see anything there ( Ch. 26).
A phenomenon reported in individuals who have damage to the primary visual cortex resulting in blindness. Individuals with blindsight report that they are unable to see, yet when examined are able to indicate the presence and location of objects.