The eye has a deeper meaning.
It represents the spiritual aspect of high consciousness, but physically it represents pineal gland and also the Son (which is the black hole that was created out of the infinite - The first visible image of the invisible god (which is christ).
Christ is the visible image of the invisible God.
He existed before anything was created and is supreme over all creation.
So, what's the reason behind putting this symbol on currency?
Probably a Freemason who wanted to represent God in some way. You know they put God on all kinds of things a long time ago. Ever seen "In God We Trust"? It is on a lot of currency also. What has happened since that time and what is occurring now in society should not mean that the meaning of the symbolism has changed. Just because the Nazis used the Swastika does not mean it represents Nazism... its original meaning was tied to Buddhism and such.
What, is being represented as the "Son"?
"The Kingdom of God is within you AND is outside you" ... You need to understand reality a little better. There are two things going on... the christ within us and the christ outside us... It is called the Adam Kadmon... it is deeper than you are talking of... this video will help you...This can of course be crossreferenced against many ancient texts and including Jewish Mysticism...
Manly P. Hall - The Only Begotten Son Of The Father
Adam Kadmon is the primordial son, or the firstbegotten son and we're not. We've but the capacity of a hologram of a piece of Adam Kadmon and for the biggest part of us that part's asleep.
Secondly, a great chunk of the puzzle is uniting the duality of the world we live in. The world is by design created as dual in nature - the within and the without, the harlot and the saint, the oxygen we're breathing that slowly kills us etc... We're all a piece of The Divine's manifestation onto this plane of existence.