Ophthalmoscopy of the Retinal Nerve Fibre Layer in Neuro-Ophthalmologic Diagnosis

Abstract

Summary The retinal nerve fibre layer surrounding the optic discs provides a unique clinical opportunity to view directly pathologic changes in the neural components of a major sensory pathway in the brain. Minute changes in this neural tissue are best seen in bright red-free light of a direct ophthalmoscope. This report stressing the neuro-ophthalmologic significance of peripapillary retinal signs illustrates and discusses (1) how focal axon degeneration from acute and insidious forms of optic neuropathy causes multiple slit-like thinnings in the arcuate nerve fibres before any recognizable signs of pallor or functional change occur in the optic nerve, (2) how atrophy, direct and trans-synaptic, of an optic tract causes diagnostic homonymous patterns of axon loss in the peripapillary nerve fibre layer and optic disc of the two eyes, and (3) how recognition of fundoscopic signs of hemiretinal and optic hypoplasia allows the neuro-ophthalmologist to differentiate the bitemporal or homonymous hemianopias of developmental origin from the acquired effects of brain tumour, and (4) how coarseness of striations, blurring, and opacity of the nerve fibre layer, manifestations of impaired axonal transport, help in evaluating incipient papillœdema, and various acute and subacute optic neuropathies.