This is a nerve fiber layer scan of an eye of a patient with advanced optic nerve drusen.  The black line is the nerve fiber layer thickness of this patient.  The x-axis (on the bottom) shows where on a circle around the nerve the thickness measurement is taken.  The y-axis (on the left side) gives the thickness of the nerve fiber layer in microns.  This patients average nerve fiber layer thickness is 45.88 microns which is about 1/3 normal.

On the right side is a photo of the optic nerve.  On the right bottom is a representation of the optical coherence tomography scan circling the nerve. The white lines demarcate the boundaries of the nerve fiber layer, which is on the surface of the retina. The compute calculates the thickness of the nerve fiber layer based on the distance between the two white lines on the scan on the bottom right.