Advanced visual field loss secondary to optic nerve head drusen: case report and literature review.

Background: Optic nerve head drusen (ONHD) is a relatively uncommon condition that results from calcific degeneration of axons within the optic nerve. The abnormal drusen bodies can enlarge, compressing normal nerve structures, and ultimately may result in vision loss. Drusen often are discovered through clinical evaluation with a dilated funduscopic examination.