Differently-shaped eyes in anime often correlate with different emotions and interactions. To describe this process more clearly, let’s work with three simple shapes: a circle, a polygon, and a rhombus.
The iris is the next component of the eye that we want to get right. We can play around with different sizes, however, a good rule of thumb is to cut off a bit of the upper section for eyes that are slightly more narrow.
Once we have established the basic form and shapes of the eye, we now can start to add details. Highlights are super essential, as they give more life to the eyes as well as a more realistic interaction with their environment.