The answer to this is Metaphor. This is a type of speech that refers to something by using another thing for reference. In this type of metaphor, the person is trying to say that the other person is the one who will catch his eye the most. Some people still get confused with the use of metaphors.
Some feel that they just complicate things. Some metaphors are used in order to make people understand some situations more. Through the given metaphor, the other person will know that she is appreciated and that everything she does will be noted by the person who is saying the statement.