Visual Loss in Neuro-Ophthalmology

Abstract

Optic neuropathy is damage to the optic nerve from any cause. Damage and death of these nerve cells lead to characteristic features of optic neuropathy. The main symptom is loss of vision (visual acuity and visual field damages), with colors appearing subtly washed out in the affected eye. The diagnosis is made on clinical examination. The history often points to the possible etiology of the optic neuropathy. In most of the cases, one eye is affected but it could be both. A rapid onset is typical of demyelinating, inflammatory, ischemic, and traumatic causes. A gradual course points to compressive, toxic/nutritional, and hereditary causes. The classic clinical signs of optic neuropathy are visual acuity and field defects, dyschromatopsia, and abnormal pupillary response. There are ancillary investigations that can support the diagnosis of optic neuropathy. Visual field testing, neuroimaging of the brain and orbit are essential in many optic neuropathies including demyelinating and compressive. In the last decade, increase of use new technology for optic neuropathies evaluation including multifocal visual evoked potentials and optic coherence tomography. Long standing of optic neuropathy is described by pale optic disk or optic atrophy, which means damage and death of these nerve cells or neurons.