Contralateral field defect in traumatic globe luxation with optic nerve injury

Abstract

ABSTRACT Clinical relevance: Traumatic globe luxation is rare vision-threatening event. Besides causing loss of vision in traumatised eye, it may also cause injury to contralateral optic nerve. Any such limitation in a one-eyed patient can make him crippled in his day-to-day activities. Here we hypothesise cause of contralateral field defect in such patients. Background: Traumatic globe luxation is a rare event that leads to profound vision loss due to injury of the ipsilateral optic nerve and rarely a visual field defect in the contralateral eye. Through this communication, we report similar case scenarios and intend to hypothesize the mechanism that results in the occurrence of the contralateral visual field defect. Methods: It is a retrospective, observational study. All cases with traumatic globe luxation were enrolled. Visual field analysis of the contralateral normal eye was main outcome measure. Results: Four patients with traumatic globe luxation and optic nerve injury were studied. There was complete loss of vision in the traumatised eye in all the patients. One patient had complete transection of the optic nerve, whereas in three patients, the course of the optic nerve was intact, on imaging. Three patients had quadrantanopia in the contralateralnormal eye for which oral steroids were given. At 1-month follow-up, there was complete recovery of the visual field defect in two patients. We noticed that all the three patients with an intact course of the ipsilateral optic nerve had quadrantanopia in the contralateral normal eye. Conclusion: We hypothesize that in scenarios where globe luxation is associated with incomplete transection or no transection of the optic nerve, a continuous long standing stretch on the optic nerve, transmits the pulling force to the chiasma which might result in a contralateral field defect as compared to those associated with the complete transection of the optic nerve.