I see a lot of photos where you can not see the person's eyes in the photo. Not because the eyes are not in the photo, but because there is a lack of a "catch light" in the eyes making them look blank and lifeless. I call this the "Zombie" or "Dead Eye" look. (In the movies when they want to make a person look like the walking dead, the first thing is to darken the eyes). There's a saying that "The eyes are the window to the soul" and when there's no light in the subjects eyes, the subject looses some of the life in the photo.