chromatopsia

   Also referred to as chromopsia. Both terms stem from the Greek words chroma (colour) and opsis (seeing). They are used to denote a temporary aberration in colour vision, characterized by an excessive sensitivity to one particular colour. As a result, individuals with chromatopsia perceive white objects and stimuli as coloured, and some coloured objects and stimuli as tinged. Traditionally, the group of chromatopsias is divided into *cyanopsia (blue vision), * chloropsia (green vision), * xanthopsia (yellow vision), *erythropsia (red vision), and *ianothiopsia (violet or purple vision). Pathophysiologically, the group of chro-matopsias is divided into central (i.e. cerebral), retinal, and optical variants. Chromatopsias associated with cerebral cortical lesions or processes are also referred to as coloropsia. Etiologically, central chromatopsia is associated primarily with head trauma, cerebrovascular disorders, psychiatric disorders, and intoxications. They tend to arise and disappear quite suddenly. They can be either monocular or binocular in nature, and they can occasionally present in the form ofa coloured *flicker-scotoma. Chromatopsia of a retinal origin is associated primarily with changes in the macular area, due to macular oedema or central serous retinopathy, for example. Some types of retinal chromatopsia may be due to systemic digitalis or tridione intoxication. Chromatop-sias of optical origin are associated primarily with corneal opacities, cataract, vitreous haemorrhage, fluorescein angiography, and icterus. Conceptually and phenomenologically, chromatopsia should not be confused with * colour vision deficiency or * colour-processing deficits.

   References

   Pinckers, A., Cruysberg, J.R.M., Liem, T.A. (1989). Chromatopsia. Documenta Ophthalmologica, 72, 385-390.

   Wernicke, C. (1900). Grundriss der Psychiatrie. Leipzig: Verlag von Georg Thieme.