Radiation Optic Neuropathy

Radiation optic neuropathy (RON) is a rapid-onset, severe, challanging optic neuropathy that can cause unilateral or bilateral vision loss, which may occur years after radiotherapy. RON mostly occurs with radiation therapy exceeding 50 Gy to the visual axis. The risk of RON occurring at radiation doses between 50-60 Gy is 5% within 10 years. Since RON can cause acute, irreversible, unilateral or bilateral profound vision loss, patients at risk need to be carefully monitored. Early diagnosis and treatment is very important to prevent serious vision loss. The first test to be performed in patients with suspected RON is fat-suppressed, non-contrast brain MRI, which is recommended to be performed in 3 mm and thinner sections. In addition; lumbar puncture and Optical coherence tomography angiography (OCT-A) are helpful tests in the differential diagnosis. Anti-VEGF molecules have been shown to be effective in treatment, which aim to reduce edema and retinal hemorrhages. Hyperbaric oxygen therapy is not a proven treatment for RON – but there are some studies about it’s speculated effect. Studies presenting the success rates of this treatment are quite limited in number. Systemic corticosteroids, heparin, warfarin and other anticoagulation treatments have not been proven successful in the treatment of RON. RON is one of the optic neuropathies that chronically damages visual function. The prognosis is generally poor. It is important for the patient and the physician to be aware of RON after radiotherapy and to minimize the possibility of permanent damage through preventive measures that can be taken. Since there are no definitive treatments for RON, preventive medicine is of great importance.