La vision des couleurs de l'enfant et son exploration

Colour vision in humans relies on a trichromatic system linked to the presence of three types of cones, each one possessing its own specific visual pigment. The alterations in genes coding for these pigments explains the occurrence of hereditary congenital dyschromatopsia. This perception, based on “red-green” and “blue-yellow” antagonisms subsequently reaches the primary visual cortex through the parvocellular and koniocellular routes. This anatomical data explains the differences in types of acquired dyschromatopsias according to their damage. The study of the chromatic sense can help to orient the diagnostic when confronted with an unexplained loss of visual acuity, since different types of acquired dyschromatopsia correspond to retinal or optical nerve damage. Finally, it has an essential place in the screening for an onset of iatrogenic damage during many treatments. The revelation of a congenital dyschromatopsia permits one to help early on a child and its family to choose its professional orientation. Study of colour vision is a simple and reproducible examination, the indications of which are multiple whatever the age of the patient. The tests dedicated to this examination each have their own indications, and present limits that should be taken into account. This is why this examination is problematical in older children and in adults. Conversely, it is necessary to associate and confront several tests in young children before drawing any conclusions.