Which type of color vision deficiency affects the blue-yellow vision spectrum?

Tritanopia is a specific type of color vision deficiency that affects an individual's ability to perceive the blue-yellow spectrum. This condition occurs due to the absence or malfunction of the short-wavelength sensitive cones (S-cones) in the retina, which are primarily responsible for detecting blue light. As a result, individuals with tritanopia often have difficulty distinguishing between blues and greens, as well as yellows and purples.

In contrast, conditions like protanopia and deuteranopia primarily impact the red-green spectrum, referring to the long-wavelength and medium-wavelength sensitive cones, respectively. Rod monochromacy involves the absence of cone function altogether, leading to a reliance on rod cells for vision, which only enables perception of light and dark rather than color, thus affecting overall visual experience rather than specifically targeting the blue-yellow spectrum.

The distinction of tritanopia lies in its unique impact on color perception, specifically targeting the blue-yellow region, making this answer accurate for the question posed.