noun
heterochromia iridis; differently colored eyes
Medical term for a condition where the irises are different colors. Used in clinical or descriptive contexts.
彼女は虹彩異色症で、右目が青く左目が茶色い。
She has heterochromia iridis; her right eye is blue and her left eye is brown.
オッドアイ is a common, casual term for differently colored eyes, often used for animals or in anime, while 虹彩異色症 is the formal medical term.
Compound of 虹彩 (iris) + 異色 (different color) + 症 (condition/disease). A modern medical coinage.