[Optic nerve evulsion: Metaanalysis]

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.

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.

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.

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.