maskun

maskun (uncountable)

1. A congenital form of color blindness found in parts of Micronesia.
   • 2012, Oliver Sacks, The Island of the Colorblind:

     Some of the Ishihara plates, paradoxically, cannot be seen by color-normals, but only by achromatopes—these have dots which are identical in hue, but vary slightly in luminance. The older children with the maskun were particularly excited by these—it turned the tables on me, the tester—and they jostled to take their turns pointing out the special numbers that I could not see.

• Kumans, unmask