Deviant axons and glaucomatous damage

The course of ganglion cell axons from the retina to the optic nerve is predictable and has been known accurately for over a century. The arcuate arrangement of the axons temporally and the presence of the median raphé were first described by the anatomists Michel1 and Dogiel2 in the latter part of the 19th century. Vogt correctly deduced the arrangement of the superficial nerve fibres in the retina when, in 1913, he observed the retinal nerve fibre layer ophthalmoscopically with the aid of red-free light.3 In contrast, the anatomical orientation of retinal nerve fibres within the optic nerve head has been the subject of considerable debate. Before 1930, the common view was that nerve fibres from the peripheral retina entered the central portion of the optic nerve head.4 Loddoni established that the reverse was true: nerve fibres from the far retina entered the peripheral optic nerve head while more central fibres occupied a central position in the nerve.5 However, the anterior-posterior relation within the retinal nerve fibre layer remained unclear. The work of Wolff and Penman supported the view of the older literature that long retinal axons occupied a scleral position in the nerve fibre layer, while more central axons …