Dr Christina Moutsiana and a team of collaborators published a case study of a person who has suffered unexplained vision loss. Despite showing no evidence of any problems or dysfunction in her early visual pathway and pretty much normal retinotopic maps in the visual cortex, she has progressively lost her vision. The scotoma grew mostly in a clockwise fashion across her visual field without respecting the meridians, which would typically be a sign of a cortical source of the vision loss. In addition, she has severe deficits with visual processing, especially any visual functions that involve spatial integration, such as contour integration, illusory shapes, or detecting global motion. We cannot explain this pattern of results but it is a very interesting case that should be part of the scientific literature.
Moutsiana, C, Soliman, R, de-Wit, L, James-Galton, M, Sereno, MI, Plant, GT, & Schwarzkopf, DS (2018). Unexplained progressive visual field loss in the presence of normal retinotopic maps. Frontiers in Psychology 9: 1722.