Yeah, it's entirely possible to see how people feel by looking at their eyes and, as someone else said, eyebrows. They're basically the most personal part of the face. They make people look distinct. That's why they cover them up sometimes in, like, evidence in courtrooms, or whatever, when they want to keep the identity of somebody hidden. Obviously the rest of the face is important too, but the eyes are by far the most important part.
I think it's more the eyebows that show what you are feelling, raise eyebrows means suprised, when eyebrows are frowned you are angry, when you eybrows tilt then you are sad. Or something along those lines. So it's not in the eyes but the eybrows and forehead together.