#weirdcase

In this case, we can use Claude Monet as example.

Late in his life, Claude Monet developed cataracts. As his lenses degraded, they blocked parts of the visible spectrum, and the colors he perceived grew muddy.  He agreed at age 82 to have the lens of his left eye completely removed.With his lens removed, Monet continued to paint. Flowers remained one of his favorite subjects. Only now the flowers were different. When most people look at water lily flowers, they appear white. After his cataract surgery, Monet's blue-tuned pigments could grab some of the UV light bouncing off of the petals. He started to paint the flowers a whitish-blue.

Tetrachromacy is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cells in the eye. The normal explanation of tetrachromacy is that the organism's retina contains four types of higher-intensity light receptors (called cone cells in vertebrates as opposed to rod cells which are lower intensity light receptors) with different absorption spectra.

In its simplest form it is best described as a “union of the senses” whereby two or more of the five senses that are normally experienced separately are involuntarily and automatically joined together. Some synaesthetes experience colour when they hear sounds or read words. Others experience tastes, smells, shapes or touches in almost any combination.