Anomalous Trichromacy

A category of colour vision deficiency where all three types of cone cells are present but one type has a shifted sensitivity range, resulting in altered colour perception that is less severe than dichromacy. The three forms are protanomaly (shifted red cones), deuteranomaly (shifted green cones), and tritanomaly (shifted blue cones). People with anomalous trichromacy experience a compressed colour space but retain some three-dimensional colour perception.