This area represents the axons of the ganglion cells within the innermost aspect of the retina. During the OCT scan acquisition process, the thickness of the RNFL is calculated from thousands of locations. It is then displayed in several ways:
Recall that it is the axons of the ganglion cells that conglomerate at the optic disc to form the neuroretinal rim (NRR) tissue. The utility of RNFL as a surrogate measure for Glaucomatous Optic Neuropathy has been well proven in clinical research.