“Cortical blindness” is bilateral visual loss due to dysfunction of both occipital lobes. It is diagnosed on the basis of behavioral observations that reflect problems in seeing, even though the patients can hardly describe their visual loss. Therefore, laboratory tests such as computed tomography, magnetic resonance imaging, electroencephalography, and visual evoked cortical potentials (VECP) must be relied on to provide the diagnosis of cortical blindness.

Among such objective tests, the VECP has raised the hope that it could be used to quantify functional visual loss because correspondences between subjective visual functions such as visual acuity, color vision, and central visual field defects and the VECP have been reported to occur. However, the results appearing in the literature are still in conflict. In the present chapter, the VECP and cortical blindness will be described.