[Colour vision and acquired colour vision disturbances. Part I: basic aspects].

Colour vision is the most sensitive sensory ability of the human eye, making it possible to distinguish several million nuances of colour. The physiology of colour vision has meanwhile been researched in depth, including the genetic and biochemical principles. This knowledge has facilitated a better understanding of the results of clinical tests on colour vision. These clinical tests provide useful information on the aetiology of very different clinical pictures in ophthalmology and as such are important for the diagnosis of these diseases. Acquired colour vision deficiencies in patients with systemic vascular disease are early signs of dysfunctional microcirculation and play a role in the early diagnostic work-up. Part I of this review summarizes the basic principles of colour vision and its disturbances. Congenital and acquired colour vision disturbances are distinguished. The second part then describes the most commonly employed examination procedures to assess colour vision.