When one of a character’s eyes is completely different from the other. This isn’t just Heterochromia and/or Mismatched Sclera - the eyes need to be completely unlike each other. Frequently seen with Cracked Kawaii Mask where the eye on the mask looks cute, while the eye beneath the mask tends to appear stressed or unnerving. Another example would be a Doll with one regular eye and an eye made out of a sewn-on button.
A Glass Eye wouldn’t apply because it’s functioning as a false eye, not a real one. You want both eyes to be open and functioning for the character here.