瞳 is one of the most commonly used Japanese kanji, and it also has a lot of special readings in addition to the standard onyomi and kunyomi readings.
ONYOMI 音読み
ひとみ hitomi
KUNYOMI 訓読み
ドウ dou トウ tou
Examples
あなたの瞳に、吸い込まれそう!I feel like I’m being drawn into your eyes.私たちのひとみは日のあたる所では収縮する。The pupils of our eyes contract in sunlight.その瞳から一粒の涙が、流れ落ちた。A tear ran down from that eye.彼女の濃いブルーの瞳がとても印象的だった。Her eyes, a deep blue, were quite impressive.