Pupil
noun
The kanji and the word are exactly the same. That means they share meanings as well. Remember, this is the eyeball pupil.
A person's (ひと) seeing (見) ability comes from their pupil. That's how you can remember ひとみ.
父の再婚相手の気怠い瞳を見ると、いつもたじろいでしまいます。
When I look at my stepmother’s listless eyes I always end up wincing.