Normal

This is a printout from a specialized camera that evaluates the optic nerve fibers inside the eye. A normal eye has thick fibers above and below the optic nerve coming from the retina. The thin green (for right eye) and purple (for left eye) lines fall within the normal range of the wider bands in the bottom graph as seen to the left.

Abnormal

In this case of glaucoma, note the loss of nerve fiber thickness and how the thin lines are way below the expected range in the bottom graph. The GDX combined with visual field testing provides the earliest measurements in the detection of glaucoma.