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Nonarteritic anterior ischemic optic neuropathy: Epidemiology, pathogenesis, and etiologies

Authors
Madhura Tamhankar, MD
Nicholas J Volpe, MD
Section Editor
Paul W Brazis, MD
Deputy Editor
Janet L Wilterdink, MD

INTRODUCTION

Ischemic optic neuropathy is the most common optic nerve disorder in patients over age 50 years [1]. Ischemic optic neuropathy is generally categorized as anterior (affecting the optic disc) versus posterior (retrobulbar) and as arteritic versus nonarteritic. Anterior involvement is usual with both arteritic and nonarteritic ischemic optic neuropathy (AION and NAION).

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common form of ischemic optic neuropathy. It is an idiopathic, ischemic insult of the optic nerve head characterized by acute, monocular, painless visual loss with optic disc swelling.

This topic will discuss the epidemiology, pathogenesis, and causes of NAION. The clinical features, diagnosis, treatment, and prognosis of NAION are discussed separately. Other forms of ischemic optic neuropathy and other optic neuropathies are discussed separately. (See "Nonarteritic anterior ischemic optic neuropathy: Clinical features and diagnosis" and "Nonarteritic ischemic optic neuropathy: Prognosis and treatment" and "Clinical manifestations of giant cell (temporal) arteritis" and "Optic neuropathies".)

VASCULAR ANATOMY

The optic nerve head (prelaminar and laminar portions) is supplied by 15 to 20 short posterior ciliary arteries that are derived from the ophthalmic artery and also by arterial branches from the anastomotic circle of Zinn-Haller [2-4]. The circle of Zinn-Haller itself is fed by the short posterior ciliary arteries, branches of pial arterial network, and choroidal vessels (figure 1).

This vascular supply may demonstrate distinct upper and lower halves consistent with altitudinal damage to the optic nerve head [5]. (See "Nonarteritic anterior ischemic optic neuropathy: Clinical features and diagnosis".)

                       

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Literature review current through: Nov 2016. | This topic last updated: Tue Aug 18 00:00:00 GMT 2015.
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