1. Duplicate the image
2. On the second layer of the image, which is the duplication, desaturate it
3. Go in with your eraser and only erase the pupil part
4. Go back to the original layer/image and raise the contrast and brightness a bit.
Optional:
1. Invert the colors
2. Select the pupil and colorize it red
3. PSD Cut the image, and place it on top of a red/black background
4. Lower the brightness of the image.
Actually that looks pretty good if the left side wasnt so black so you could see some of the facial features it would look better, and around the eyes lighten up a bit so you can see the redness that it looks like you added in.
Yeah, I am going to do a better one now, because I have never done stuff like that and I guess its not a bad time to start practicing. I'll edit it in when I am done.
Edit;
Thats a little better, I think I messed up pretty bad near the neck/chin though.