Evaluation of sense of colour
In the case of true colour blindness, you hardly see any colours, but rather variations of light and dark. Fortunately, this condition is very rare. Colloquially speaking, colour blindness is used to refer to a red–green impairment, which means those affected can only differentiate between the colours red and green with great difficulty, if at all. Visual colour impairments are usually inherited, but can also be triggered by illness, medication or intoxication.
Diagnosis and treatment
Healthy sensory cells (cones) in the retina register the different wavelengths of light (red, green, blue violet) and thereby recognise 160 different shades of colour. If the visual impairment is hereditary and/or present in the family, early examination is sensible. Otherwise, the impairment only becomes noticeable in important situations (traffic lights), where the colours are not recognised. There is currently however no therapy for colour impairments or colour blindness.