Intravitreal Bevacizumab for Non-Arteritic Anterior Ischemic Optic Neuropathy

Overview

Non-Arteritic Ischemic Optic Neuropathy (NAION) is a disease producing swelling of the optic nerve (the "cable" going from the eye to the brain) resulting in decreased vision. About 15% of patients will experience NAION in the second eye; many of these patients will be left legally blind. Currently, there is no treatment for NAION and for patients in whom the second eye becomes involved by the disease the outcome can be devastating. The investigators are conducting a study where the investigators will inject a medication into the involved eye of patients with NAION. This medication might decrease the swelling of the optic nerve and improve their vision in that eye.

NAION produces an ischemic insult in the optic nerve head presumably due to the hypoperfusion of the short ciliary arteries that supply it. This leads to the release of vascular endothelial growth factor (VEGF) and swelling of the affected area of the nerve. Vascular endothelial growth factor (VEGF) causes a rapid and reversible increase in vascular permeability and thus vasogenic edema of the affected area of the optic nerve head. Subsequently, increased pressure from the swelling of the affected segment causes compression and infarction of the previously not affected parts of the optic nerve by creating a sort-of "compartment syndrome". Bevacizumab is a known anti-Vascular Endothelial Growth Factor (VEGF) agent. It is the investigators hypothesis that by injecting bevacizumab intra-vitreally the vasogenic edema will be reduced, preserving viable but threatened optic nerve tissue. One recent case report described a patient with sequential NAION treated with intra-vitreal bevacizumab who demonstrated significant improvement in visual acuity and on visual field testing (1). An editorial in the same issue of the Journal of Neuro-Ophthalmology in which this article appeared suggested that if the small studies evaluating intra-vitreal injections of bevacizumab in NAION would support its use in this disease, a large multi-center trial could be planned (2). Intra-vitreal injections of bevacizumab have proven to be very safe in treatment of age-related macular degeneration (3). Because the patients that the investigators are planning to enroll in this study are faced with the real possibility of blindness with no therapeutic modality currently available to improve their visual outcome, the investigators believe that offering them intra-vitreal bevacizumab injection that might halt the progression of the visual acuity and visual field loss if our hypothesis is correct, would greatly improve their chances of avoiding blindness.