Investigating colour vision

Before investigating colour blindness at length Dalton had realised that there was something unusual in his sight. On a number of occasions he mistook red items for green ones. In the 1790s he undertook detailed investigation and came to the conclusion that normal colour vision was inherited in some way and that his colour blindness was due to the fluid in his eye being tinted blue. We now know that Dalton's defective vision was attributable to a defect in the red receptors of his retinas. This condition is still referred to as 'Daltonism'.

It was not until the end of the eighteenth century that a full investigation of the phenomenon of defective colour vision was made.

The first detailed account was published by John Dalton in 1794. Dalton was a highly respected scientist and the originator of the atomic theory of matter. Both Dalton and his brother had defective colour vision.