Colour blindness , or colour vision deficiency , affects around 300 million people worldwide . It occurs due to an abnormality in the cone cells in the eye 's retina , which detect different wavelengths of light . One or more of the cones will be missing or wo n't function normally , meaning the person can not see all colours . US--based technology company EnChroma have developed new glasses which can boost people 's colour vision . Touching film shows people seeing their children 's drawings , sunsets and flowers in colour for the first time .
Colour blindness , or colour vision deficiency , affects around 300 million people worldwide . It occurs due to an abnormality in the cone cells in the eye 's retina , which detect different wavelengths of light . One or more of the cones will be missing or wo n't function normally , meaning the person can not see all colours . US-based technology company EnChroma have developed new glasses which can boost people 's colour vision . Touching film shows people seeing their children 's drawings , sunsets and flowers in colour for the first time .