Symbolism, Imagery, Allegory
In one sense, you could make the argument that Love's Labour's Lost is all about the eyes. Berowne is especially obsessed with them. They are the vehicles through which knowledge reaches the mind, whether from books or from looking at a beautiful woman (the latter being Berowne's preferred method). They are the feature that makes one fall in love. You could write a whole term paper on eyes in Love's Labour's Lost.