Distribution of Damage to the Entire Retinal Ganglion Cell Pathway

Abstract

Glaucoma causes degeneration of the retinal ganglion cell, including axons at the optic nerve head (ONH) and the retinal ganglion cell axons in the nerve fiber bundles (NFBs), and at the retinal ganglion soma via apoptotic cell death.¹ We define the retinal ganglion cell–axonal complex (RGC-AC) as a set of neighboring ganglion cells in the retinal ganglion cell layer (GCL), together with their axons, forming an NFB in the retinal nerve fiber layer (NFL) until their exit from the eye in the ONH. An RGC-AC has multiple segments, including a cell body segment located in the retinal GCL, multiple NFB segments located in the retinal NFL between the cell body and the ONH, and an ONH segment located in the neural rim of the ONH. The distribution and path of the RGC-AC have been studied by visually examining the histologic structure of stained retina^2-5 and of its NFB part by examining patterns of visual field defects.^6,7 More recently, Jansonius et al⁸ mathematically modeled the NFB trajectories using manual tracings in fundus photographs of patients with glaucoma. Detailed knowledge of the exact amount and distribution of glaucomatous damage to the entire RGC-AC is required for a topographically precise prediction of circumscribed visual field loss and has the potential to improve the diagnosis and management of glaucoma.⁹