Drusen-associated visual field defects and hemorrhages.

Retinal hemorrhages and visual field defects can occur as complications of optic nerve drusen. The visual defects of optic drusen are of three types: (1) concentric constriction of the field, (2) enlargement of the blind spot, and (3) nerve fiber bundle defects. Retinal hemorrhages also fall into three categories: (1) splinter hemorrhages overlying the disk, (2) vitreous hemorrhages, and (3) subretinal hemorrhages. The unusual disk vasculature associated with drusen is probably responsible for the retinal hemorrhages and may be the primary defect in the pathogenesis of drusen. Altered axoplasmic transport and abnormal axonal calcium metabolism have also been thought to be significant in the pathogenesis of drusen.