Different Lights Do Make Me Strange

Riddle: Different lights do make me strange, thus into different sizes, I will change. What am I?

Answer: I am the pupil of an eye.

Source: https://www.riddles.com/index.php/221

Different lights do make me strange, thus into different sizes, I will change. What am I? — Different lights do make me strange by Anonymous v1.

Riddle: Different lights do make me strange, thus into different sizes, I will change. What am I? Answer: I am the pupil of an eye. — by Anonymous v2.