Exudative Optic Neuropathy

Outline

Overview
Signalment
Signs
Causes and Risk Factors

BASICS

Overview

Presents as white to gray, raised nodular masses spread across the surface of the optic disc, which is usually swollen/edematous. Large lesions may obscure the optic nerve head entirely
Retinal and optic disc hemorrhages may also be present

Signalment

This rare condition is observed more frequently in older horses (>15 years).

Signs

Sudden onset of total blindness in bilateral cases
Dilated pupils

Causes and Risk Factors

Definitive cause is unknown
Possible etiologies include trauma, acute massive systemic hemorrhage, and systemic infectious diseases, such as Streptococcus equi spp. equi, equine herpesvirus 1, and Actinobacillus equuli

Diagnosis ⬆ ⬇

Outline

Differential Diagnosis
CBC/Biochemistry/Urinalysis
Other Laboratory Tests
Imaging
Other Diagnostic Procedures
Pathologic Findings

DIAGNOSIS

Differential Diagnosis

Must be distinguished from:

Benign proliferative optic neuropathy in aged horses with otherwise normal findings in a visual eye
Other conditions presenting as masses on the optic nerve head, such as optic nerve neoplasia, traumatic optic neuropathy, and ischemic optic neuropathy
Other causes of blindness, such as those due to cataracts, glaucoma, equine recurrent uveitis, retinal detachment, central nervous system disease

CBC/Biochemistry/Urinalysis

N/A

Other Laboratory Tests

N/A

Imaging

N/A

Other Diagnostic Procedures

Diagnosed by characteristic funduscopic appearance.

Pathologic Findings

White nodules protruding from the optic nerve head anteriorly into the vitreous are observed macroscopically; gitter cells from the optic nerve are observed microscopically.

Treatment ⬆ ⬇