Moreland Match

The Moreland Match is the blue-yellow equivalent of the Rayleigh Match, which detects red-green color vision defects. It is used in blue-yellow Anomaloscopes, such as the Moreland Anomaloscope and was devised in 1979.

Typically an observer is shown a circle split into two semicircular color fields. One of those fields is a dichromatic mixture of violet-blue (~436 nm) and cyan-green (~490 nm) light. Unlike the Rayleigh Match, the other field is not a monochromatic light where the brightness is adjusted. Rather, it is a dichromatic mixture of cyan-blue (~480 nm) light and its Complementary Color yellow (~580 nm), which acts to desaturate the cyan-blue without changing its hue. The observer adjusts the relative amounts of each field in order to make the two colors appear identical.