John Dalton carried out the first serious investigation of color deficiency in 1794. He became aware that his own color vision differed to that of other people, in particular he was unable to distinguish between certain colors and was unable to see deep red colors. Dalton found similar defects among his brothers and started to investigate the prevalence of the condition using a series of colored ribbons. Dalton believed that the cause of his condition lay in a blue coloration in the vitreous humour of his eye. This explanation was subsequently disproved by a post mortem examination carried out at his own request. However, the term 'Daltonism' has persisted to describe this form of color deficiency.
Congenital color deficiency occurs as a result of inherited photopigment abnormalities. Because of the X-linked mode of inheritance, color vision defects are much more common in men than women. In some cases one or more cone types may be absent altogether; in other cases one of the three types of cone may contain photopigment which differs in spectral sensitivity compared to the normal. Thus the broad classification of color vision deficiencies is based on the number of photopigments present (monochromat, dichromat and trichromat). In cases where one type of photopigment is missing or anomalous, the terms protan, deutan and tritan (from the Greek meaning first, second and third) are used to describe which of the photopigments is affected (long, medium and short wavelength sensitive photopigment respectively).
How do Color Defectives See the World?
约翰道尔顿在 1794 年对色觉缺乏症进行了第一次严肃的调查。他意识到自己的色觉与其他人的不同，尤其是他无法区分某些颜色，也无法看到深红色.道尔顿在他的兄弟中发现了类似的缺陷，并开始使用一系列彩色丝带调查这种情况的普遍性。道尔顿认为，导致他病情的原因在于他眼睛的玻璃体液呈蓝色。这一解释随后被应他自己要求进行的解剖检查所驳斥。然而，“Daltonism”一词一直用来描述这种形式的颜色缺陷。 注释：道尔顿不仅发现了色盲现象,作为一名孜孜求索的科学家,他还提出死后捐出眼睛供科学研究,用以找出色盲的原因。不过受当时科学水平的局限,没法给出正确结论。但道尔顿的遗愿在1990年得到了实现，英国科学家对他保存在皇家学会的一只眼睛进行了 DNA 检测,验证了他确实是 XbY 红绿色盲患者。
先天性色素缺乏症是由于遗传性光色素异常引起的。由于 X 连锁遗传模式，男性比女性更常见色觉缺陷。在某些情况下，可能完全不存在一种或多种锥体类型；在其他情况下，三种类型的锥体中的一种可能含有与正常相比光谱灵敏度不同的感光色素。因此，色觉缺陷的广泛分类是基于存在的光色素的数量（monochromat、dichromat和trichromat）。在一种类型的感光色素缺失或异常的情况下，术语 protan红色盲、deutan绿色盲 和 tritan蓝色盲（来自希腊语的意思是第一、第二和第三）用于描述哪些感光色素受到影响（分别是长、中和短波长敏感的感光色素） ).