The ray of light peeking through the crack creates a blinding effect on the subject. The light is so bright that it blinds her vision, covering her eyes in the photo. The black and white filter makes the ray of light even more bright.
"Though this picture is simple. I have done black and white photography for many years and my favorite element of design is contrast. The contrast in this photo takes it from simple to interesting." I think this a fine example of contrast/black and white.