Fundoscopic appearance of a nerve-fibre-bundle defect.

Focal destruction of nerve-fibre bundles is one of the pathological common denominators of diseases involving the optic nerve, the optic papilla, or the superficial layer of the retina. Since Bjerrum (i 89 I) and Ronne ( g909, 19 I 3) first identified arcuate defects in the visual field as the perimetric correlates of defects in arcuate nerve fibres of the retina, quantitative perimetric studies have pre-empted ophthalmic interest for early diagnosis and assessment of these nerve-fibre-bundle defects (NFBDs). Direct visualization of NFBDs by ophthalmoscopy would provide the obvious advantages of an objective diagnostic technique, but the clinical feasibility of such a method has never been demonstrated. Vogt (19I3, 1917) pioneered direct ophthalmoscopic techniques for observation of retinal nerve fibres using a special type of illumination in which long (red) wave lengths were selectively filtered from white light emitted from a carbon arc. This red-free light greatly enhances visibility of superficial retinal reflexes, particularly the striated reflexes from the nerve-fibre bundles. We have adapted Vogt's method for evaluation of retinalnerve-fibre abnormalities in patients with optic nerve disease and have repeatedly observed narrow slit-like gaps in the peripapillary nerve-fibre reflexes. In each instance there were corollary defects in the visual field. This report documents the fundoscopic appearance of small slit-like NFBDs in the arcuate nerve fibres of the retina, and describes the associated defects in the visual field as recorded by quantitative kinetic and static methods with the Tubingen Perimeter.