The eye of Sauron appears to us. At once we might think of the evil eye, a spell or hex. But this is no spell it is Sauron, the Dark Lord himself. Truly the eye is evil but it is not because it is a manifestation of evil but the evil lord itself. Is it because it might be the spirit of evil that regards us that we sense evil? Maybe. But what makes this such an evil spectacle?
Above all it is an abstract eye. It is an eye reduced to its elements. In Fellowship evil is mostly an abstraction. The Nazgul are an abstracted man, reduced to black. The Dark Lord is an abstracted eye, reduced to flame red. Everything is reduced, it is lidless. This abstraction unnerves us. We see some humanity there, as we do with the Ringwraiths, but it is ultimately degraded, reduced to a single aspect and one element. This eye is an elemental evil.
The eyes are a window to the soul but this single eye is a gateway to evil . The Dark Lord is a black hole in middle earth. Sauron is a singularity of dark with its centre at the pupil of this eye. If we were to fall into it it would transport us to another place. This eye takes, it never gives. It pulls to itself, never radiates.
The agents of this eye, the wraiths will stab and harm while the eye itself pulls, draws our own soul towards itself as an act of domination by absorption. So the eye is a twisting vortex. It is the eye of the storm of Mordor. A place of stillness at the centre of evilís kingdom but it is as a poison pool on the way to Mount Doom. It is certainly not the gaze of Galadriel which,by contrast, penetrates to gaze within and offer wisdom.
How do we see the eye in this picture. We are looking straight at it. But we could also be looking down like into a well. The eye will regard you like this, it will look at you then you will find yourself looking down, deep into the dark where you will fall.
The fire of the eye is not to warm you but to burn you. The fire would reduce you as the eye itself is a reduction. What it leaves it would take. To Mordor it would take you.