• Written By: Howard Pomeranz, MD, PhD
    Neuro-Ophthalmology/Orbit

    This retrospective case series in the Journal of Neuro-Ophthalmology reports on four consecutive patients who presented with unilateral or asymmetric bilateral radiation optic neuropathy (RON) and were treated with hyperbaric oxygen (HBO) and oral corticosteroids.

    Vision was preserved in the less affected eye of the two patients treated earliest. The authors conclude that if patients are identified early and prior to the development of optic nerve pallor, timely treatment with oral corticosteroids and HBO may result in preservation of vision in the less affected eye despite optic nerve enhancement on MRI. However, it remains unknown whether HBO alone is sufficient for treating RON or needs to be combined with corticosteroids or other therapy, such as anti-coagulation.

    The patients ranged in age from 47 to 70 years. They all had bilateral optic nerve enhancement on MRI. They had all been given radiation doses above the accepted safe limit for avoiding RON, which for most patients is a cumulative dose greater than 50 Gy or fractionated doses greater than 2 Gy.

    All patients received more than 30 days of 100% oxygen at 2.5 atm for at least 60 minutes per day. They all tolerated HBO therapy well, although one patient experienced a reversible myopic shift of -4.50 D.

    No patient showed improvement in the more symptomatic eye. The two patients who experienced visual decline in the less affected eye began treatment seven to nine days after initial vision loss. One of these patients experienced a decline in vision from 20/25 to 20/100 in the less affected eye following treatment nine days after the initial visual loss. The other patient progressed from 20/25 to light perception vision in the less affected eye, despite treatment within seven days of noting vision loss. This patient received a large total radiation dose of 70.2 Gy and had bilateral optic nerve pallor upon initial presentation. The two patients with preserved vision were treated at two and five days after the onset of visual decline.

    Optic disc pallor appeared normal in the two patients who maintained good visual acuity, as well as in one of the patients in whom vision declined in the less affected eye.