Recent Topics About Diagnosis and Therapy of Ischemic Optic Neuropathy

Recent topics on the diagnosis and treatment of both arteritic (AION) and non-arteritic ischemic optic neuropathy (NAION) were reviewed with reference to our experience with similar cases. I have managed a patient with posterior AION. AION is rare in Japan. Posterior AION is rare even in the United States of America, where AION is encountered more frequently than in Japan. I have also encountered a patient with AION, who presented with a transient visual disturbance. Approximately 30% of all patients with AION are symptomatic, and approximately 60% of these develop permanent visual loss. We need to recognize that AION due to giant cell arteritis in the Japanese might present as posterior AION or with symptoms of transient visual disturbance. Hence, temporal artery biopsy should be performed in such patients with high levels of C-reactive protein and erythrocyte sedimentation rate; moreover, early treatment should be administered to prevent permanent visual loss. Intravenous steroid pulse therapy is the rule in the treatment of AION. Other treatment options, such as immunosuppressive therapy, are used in steroid-resistant patients and in those with recurrence during high-dose steroid therapy and past medical history of severe side effects due to steroids. The efficacies of drugs like tocilizumab and methotrexate have been investigated, and the evidence regarding their effectiveness has not been established. Newly developed fundus cameras have contributed to new insights regarding the diagnosis of NAION. Some investigators have found that the optic nerve blood flow is significantly decreased using laser speckle flowgraphy and that the vessel density in the optic disc is significantly reduced using optical coherence tomography angiography in patients with NAION. We hope that newer machines are developed for the diagnosis of NAION. There is no effective treatment for improving the vision in patients with NAION. We have investigated the effectiveness of L-arginine, which was effective in the rat model of NAION. However, we could not confirm the effectiveness of L-arginine in human patients with NAION. A treatment trial of QPI-1007 involving patients with NAION is ongoing. We hope that this medicine will be effective in patients with NAION.