Case report: hyperbaric oxygen and MRI findings in radiation-induced optic neuropathy.

Hyperbaric oxygen (HBO2) therapy has been utilized in conjunction with systemic corticosteroid administration for treating radiation-induced optic neuropathy (RON) with varying success. We present the case of a 78-year-old female with RON who received two courses of HBO2 (without corticosteroids) and also pre- and post-treatment magnetic resonance imaging (MRI) of her brain. Her visual acuity subjectively and functionally improved throughout her first course of 30 treatments, including regaining the ability to ambulate independently, but subsequently deteriorated following completion. A second course of 40 additional treatments was prescribed; the patient's visual symptoms subjectively improved once more, followed again with subsequent decline after treatment. Post-treatment MRI also showed resolution of previously visible optic nerve contrast enhancement. This patient represents the 27th reported case of RON treated with HBO2 and the first reported case of radiologic and transient symptomatic improvement without concomitant steroid use. Our case adds additional evidence to the limited anecdotal data supporting MRI correlation with RON symptoms and HBO2 in RON treatment as well.