apple of someone’s eye

いとしいもの、大切なもの、目に入れても痛くないほどかわいい

Ex

• My dog is the apple of my eye.

Reference source

• https://eow.alc.co.jp/search?q=%22apple+of+%28one%27s%7Cmy%7Cyour%7Cits%7Chis%7Cher%7Cour%7Ctheir%29+eye%22