Sycra is amazing mentor. He shared this tutorial that shows his way of drawing Realistic Eyes, Cartoony or Comics Eyes and Manga eyes.
There’s big difference in all this design types and Sycra shows it very interesting way transitioning from one form to another one.
This 55 minute video will definitely help you drawing eyes in 3 different styles.
The description reads as :
In this indepth tutorial, I show you my method for going from a realistic eye to a more stylized one that you might see in comics, cartoons or manga and anime.