Perez–Bartolome Francisco, Garcia- Vasco Lorena, Ventura-Abreu Nestor, Arcos-Villegas Gabriel, Santos-Bueso Enrique, Saenz-Frances Federico, Garcia-Feijoo Julian, Munoz-Negrete Francisco and Rebolleda-Fernandez Gema
The approach of the etiology of an optic neuropathy can be difficult for both ophthalmologists and neurologists, because neither the appearance of the optic disc, the perimetry, or the findings in Optical Coherence Tomography (OCT) or Magnetic Resonance Imaging (MRI) are specific. Clinical features common to optic neuropathies are vision loss, visual fields scotomas and dyschromatopsia. Pain is a variable feature that, when is present, suggest an inflammatory disorder. Relative afferent pupilary defect is a required clinical finding for the diagnosis of unilateral optic neuropathy. The term "Typical optic neuritis" (ON) has been widely used to design a unilateral ON that presents in a young patient with an acute or subacute presentation, with pain worsened with eye movements and generally good prognosis. In this scenario, idiopathic or Multiple Sclerosis (MS) are the most likely etiologies. Therefore, in these cases, brain MRI with gadolinium contrast should be performed in order to establish the risk of conversion to MS. OCT is a useful test to evidence the retinal nerve fiber layer and ganglion cell-inner plexiform layer changes. Any modification of the mentioned clinical pattern should be consider "atypical" and further investigation is necessary in order to discard other possibilities such as ischemic, autoimmune, compressive- infiltrative, hereditary, toxic, nutritional deficiency, posttraumatic, postradiotherapy or intracraneal hypertension. Therefore, we must follow a rational algorism from the most common cause to the most unlikely in each case, with a well-defined previous distinction of the typical and atypical features, because both the early diagnosis and treatment are overriding in the second ones.