John Dalton

... "believed that his vitreous humour possessed an abnormal blue tint, causing his anomalous colour perception, and he gave instructions for his eyes to be examined on his death, to test this hypothesis. His wishes were duly carried out, but no blue colouration was found, and Dalton's hypothesis was refuted. The shrivelled remains of one eye have survived to this day, and now belong to the Manchester Literary and Philosophical Society."

So wrote Benedict Regan in 1998, in a review of John Dalton's Colour Vision Legacy (edited by Christine Dickinson, Ian Murray and David Carden), published in the British Journal of Ophthalmology and cited by Wikipedia.

Regan goes on to confirm that Dalton suffered from deuteranopia – a lack of "the normal middle wave pigment gene". This form of colourblindness, in which the eye cannot distinguish between colours in the green–yellow–red section of the spectrum, is known as Daltonism. It affects approximately 1% of males, but a negligible number of females.

The most common form of colourblindness – affecting about 6% of males and 0.4% of females – is known as deuteranomaly. This causes a reduced sensitivity to green light; green objects (e.g. cars) appear black to sufferers in poor light.