Abstract:  Optic neuritis (ON) is one of the major causes of blindness. Based on the pathogenesis, ON is divided into two categories: typical ON associated with multiple sclerosis (MS), and atypical ON caused by other pathogenesis. Researchers classify atypical ON into many subtype by pathogenesis. Treatment and prognosis of different type of ON are variate, so to get familiar with the clinical features of various types ON is critical. Since ON is often misdiagnosed as other optic neuropathy and retinopathy in clinical practice, it is very important to differentiate it from these diseases. In this article, we summarize the clinical features of typical and atypical ON and the key points of their diagnosis, hoping to enhance our clinical knowledge on ON.