Drusen of the optic disk and aberrant axoplasmic transport. The XXXIV Edward Jackson memorial lecture.

We believe axoplasmic transport alteration is the anatomic substrate for formation of drusen of the optic disk. 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 these congenitally elevated nerve heads evolve over a period of many years through stages of atrophy and drusen formation. 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 caused by diminished production of axoplasmic material by the ganglion cell. Chronic alterations in axonal transport from any cause produce aggregates of swollen nerve fibers. These give a yellow-white appearance to the disk tissue and account for the yellow, filled-in appearance of the disk in patients with drusen, chronic atrophic papilledema, melanocytomas, and, in part, for the waxy yellow appearance of the disk in retinitis pigmentosa.