Expressions are often exaggerated when drawing cartoon eyes, as well. As an example, let’s experiment with “surprised eyes”.
I associate surprise with being “wide-eyed”, so I’m going to start by putting emphasis on showing extra whites in the eyes. We could do this in a number of ways, like opening the eye wide or perhaps making the iris smaller. We can also use the eyelids and eyebrows to help push the emotion we’re trying to convey further.