I recall a tennis match conversation between a fellow student and a class tutor in science regarding the colour outcome of a test we were completing. At the time, much hilarity ensued ( at the expense of the poor student) who was insistent that his chemical reaction had created something new and different to that what was in the text book.
Later it was concluded that he actually suffered from colour blindness. Colour blindness will make it difficult to see green, red or blue hues or a mixture of any of the three.
Obviously, learning can be troublesome if afflicted with a colour vision problem.
It is mainly genetic and will be present from birth. The macula cones are deformed or absent at birth which accounts for the remissive sense of colour.The three types of cone in the eye senses red , green or blue light. Missing cones or damaged cones will result in either not seeing these colours or a different colour or hue.
Some eye conditions like retinopathy, macula degeneration or an injury can cause damage to the macula and colour vision problem can be progressive.
Tests can be carried out by your optician which will measure your recognition of colours. Dotted test sheets are often used to see if you can pick out and read the hidden letters or numbers. A more basic test is sorting coloured counters.
What is steadfast is that an early diagnosis is required to reduce the impact on lifestyle. In children it can hamper reading progress and learning development generally. Some careers will be limited to person with colour vision problems.