Since you're replicating my style here's what I do with the eyes
1. I actually do color in the white of the eye, but it's more subtle on characters like astra who have lighter skin. I also skip it on characters like data, and I think I even skipped it on Lay once
2. If the character has a confirmed eye color, I make the pupil that color but I make it really dark. For example Astra's pupils would be a dark blue