A lot of us are familiar with the concept of "crazy eyes", and on some subconscious level we see pictures of psychotic criminals or saw people who later turned out to be criminal, and had some vague feeling just from their appearance that something was off.
When I learned about sanpaku, and the fact this notion was formalized by ancient cultures was quite a discovery for me. Sanpaku can be the whites on top or bottom, which could indicate different things.
My interest in sanpaku is spreading awareness of it, and discussing public figures who have this condition. The three whites can indicate: poor health, drug or alcohol addiction (or other addictions like gambling, etc.), hidden secrets, like a history of suffering or commiting abuse, maintaining a double life, living a lie (politicians?), deceiving people constantly, or having psychosis or a desire to hurt others.
The general theme of sanpaku was to note it and be aware as a potential warning sign. Now we know why we see politicians with crazy eyes and inherently do not want to trust them, and then we are the least surprised when they turn out to be complete frauds. The truth was in the eyes! People today put very little creedance in trusting your instincts or judging on looks, empirical evidence suggests this is a powerful tool in improving your judgement. Trust yourself and ancient wisdom, identifying sanpaku can help you avoid problems. Take a fresh look at public figures, serial killer mugshots, and early photos of people who later were close to tragedies, a lot of examples of sanpaku there.