ABSTRACT
After unilateral occipito-temporal brain injury colour vision may be lost in the contralateral hemifield or the upper quadrant (Albert, Reches, & Silverberg, 1975; Damasio, Yamada, Damasio, Corbett, & McKee, 1980; Henderson, 1982; Poulson, Galetta, Grossman, & Alavi, 1994; Short & GraffRadford, 2001; see Figure 5.1). Patients are usually aware of this disorder and report that the corresponding part of the visual surroundings appears “pale”, in “black-and-white”, or “like in an old movie”. For mapping this visual field disorder, coloured instead of white targets are used for perimetry (Aulhorn & Harms, 1972). It is important to note that in these cases light sensitivity and form vision are not impaired in the affected hemifield as in homonymous hemiamblyopia (see p. 31), indicating that the loss of colour vision is selective. Foveal colour vision may also be affected with and without the concomitant loss of colour vision in the peripheral visual field (Zihl, Roth, Kerkhoff, & Heywood, 1988). This disorder is called cerebral dyschromatopsia (Rizzo, Smith, Pokorny, & Damasio, 1993). Patients with impaired foveal colour vision typically report that fine colour hue discrimination has become difficult for them since the onset of brain injury. In our experience, professionals (e.g., painters) and female patients (possibly because they care more about colours when composing their dress or a bouquet of flowers) are more often aware of difficulties in using fine colour hues after acquired brain injury.
