The white showing beneath the iris, when you look straight ahead. Apparently, it is a sign of moral turpitude/illness.
The Japanese is 三白眼。Has this idea filtered into Taiwanese culture, or do any other cultures in Asia have beliefs about this? I think I heard that it’s also important indicator in Chinese medicine.
(I am an utter freak as I am senpaku in one eye, apparently. No protestations that I tend to oen my right eye slightly wider because I’m right handed and therefore the muscles on the right side of my body are slightly more developed would sway this person’s views. Symmetry being one of the marks of beauty, my face is completely asymmetrical and one of my eyes is noticably bigger than the other. )
A quick google informs me that Obama bin Laden has 'em.