XXXIV Edward Jackson Memorial Lecture: drusen of the optic disc and aberrant axoplasmic transport.

In summary, we believe that axoplasmic transport alteration is the anatomic substrate for formation of drusen of the optic disc. In familial cases the cause of axoplasmic transport alteration may be related to the presence of a genetically determined, small, crowded optic nerve head. We believe that these congenitally elevated nerve heads evolve over a period of many years through stages of atrophy and drusen formation. It appears that vascular malformations in the familial cases are primarily developmental; however, secondary vascular alterations may occur as the drusen enlarge. In retinitis pigmentosa, the drusen may be cuased by diminished production of axoplasmic material by the ganglion cell. As a general principle, chronic alterations in axonal transport from any cause seem to produce aggregates of swollen nerve fibers which impart a yellow-white appearance to the disc tissue, and account for the yellow filled-in appearance of the disc in patients with drusen, chronic atrophic papilledema and melanocytomas and, in part, for the "waxy yellow" appearance of the disc in retinitis pigmentosa.