[Optic nerve evulsion: Metaanalysis].

BACKGROUND

Evulsion of the optic nerve is a rare form of traumatic optic neuropathy. It is a rupture of the optic nerve at the disc without damage of its sheaths occurring in association with a blunt skull trauma or a blunt bulbar trauma.

MATERIAL AND METHODS

We searched the literature using Medline database for all articles with evulsion of the optic nerve. The bibliographies of the papers found therein were used to get a complete review. The data were analyzed with special regard to age, sex, mechanism of injury, and (if available) defects of visual field.

RESULTS

Sixty-three patients with a mean age of 22 years (range 4 to 60 years) were included in the study. In 22 patients (35 %) a partial and in 41 patients (65 %) a complete evulsion was present. In 31 patients (49 %) the cause was a small blunt object or finger that stroke the eye or entered the orbita. In 19 patients (30 %) a severe blunt skull trauma had occurred. The analysis of visual fields in eyes with partial evulsion of the optic nerve revealed a defect in the superior visual field in 6 of 12 patients and a defect in the inferonasal visual field in 3 of 12 patients.

PATHOGENESIS

Our review suggests that the most common mechanism of injury is a severe rotation of the eye leading to rupture of the optic nerve fibers and an anterior displacement of the bulbus, possibly with deformation of the posterior eye walls.