Colour vision feels effortless, but it depends on a remarkable partnership between light, specialised cells in the retina and the brain. Understanding that pathway makes colour vision differences much easier to explain.
How colour vision works
Light enters the eye and reaches the retina, where cone cells respond most strongly to different ranges of wavelengths. The brain compares those signals and builds the experience we call colour. It is not a simple camera process: context, brightness and neighbouring colours can all change what we perceive.
Why people see colour differently
Inherited colour vision differences are common and are usually present from birth. Red-green differences occur most often, while blue-yellow differences are less common. Some eye conditions, medicines and changes associated with ageing may also affect colour perception, which is why a new change deserves professional assessment.
Practical ways to improve accessibility
Never rely on colour alone to communicate an instruction. Add labels, shapes, patterns or position. Strong contrast and simple colour combinations make charts, signs and digital interfaces easier for everyone to use. A formal colour vision assessment can help when a career or safety task has specific visual standards.
A clear next step
Write down what you have noticed, when it began and which activities are affected. That simple record can make a professional conversation more focused and useful.