Central serouschorioretinopathy (CSC) is one of the most common clinical fundus diseases. In recent years, research on CSC has emerged extensively, and clinicians have gained a better understanding of the disease. Today, we have invited Professor Mingwei Zhao, who is known as “Zhao CSC”, to share with you some things about CSC. Is it common? From our ophthalmology textbooks in college, it was often said that mesoplasia is a common fundus disease, but is it as common as we think in clinical practice? There are no epidemiological studies on the incidence of mesoplasia in China, but a study in the United States found that the incidence of mesoplasia was 5.8 per 100,000 people, so it seems that the incidence of mesoplasia is not as high as we think. In clinical practice, many doctors diagnose mesoplasia when they see macular exudate. In fact, the diagnosis of mesoplasia needs to be cautious, especially in the following two cases: 1. Diagnosis of mesoplasia in the elderly: The onset of mesoplasia is closely related to hormone levels, so the elderly are not a high-incidence group. Clinical diagnosis of suspected cases in the elderly should be cautious, especially except for AMD and not PCV, which are two easily confused diseases. In elderly people with a high suspicion of M.P., detailed questions should be asked about any major psychological stimuli in their life. Is there a history of hormone application? If necessary, a whole body examination should be performed to exclude endogenous hormone elevation caused by other diseases. 2. Patients with severe vision loss: Patients with mesoplasia have vision loss, but the average visual acuity is 0.3~0.7. If the visual acuity of the patient is clinically reduced to less than 0.1, the diagnosis should be made with great caution, and the visual acuity results should be verified in detail, and other macular diseases should be carefully excluded. In order to determine the condition of a patient with mesoplasia and to guide the treatment, there are three tests that must be done. 1. OCT examination, which can visualize the size and extent of the fluid in the macula, is an important basis for diagnosis. 2. Fluorescence angiography (FA): it can visualize the leakage points in the RPE layer and is an important indicator of the activity of the middle pulp condition. 3. Choroidography (ICGA): Many doctors neglect to perform choroidography on their patients, which is not correct. Since the main pathological change of mesoplasm is the vasodilatation of the choroid, choroidography can effectively determine the extent of the lesion and is an important reference for guiding the treatment of PDT. Is the mesoplasm self-limiting? Why do I need to treat it? As many medical students know, the first thing that comes to mind when mentioning “self-limiting diseases” in ophthalmology is mesangial pulp, but is it really self-limiting? A study conducted by Prof. Albert Chan from Hong Kong tells us that the self-limiting rate of C.S.P. is only 57.9%; and that most patients will relapse and lose their vision again after a period of improvement. Studies have shown that when the disease is prolonged for more than 4 months, the function of the optic cells changes, resulting in irreversible vision loss. From these results, it is important to treat mesophoria aggressively; clinically, patients often report that vision loss, visual distortion, and central dark spots have a significant impact on work and life. Therefore, we advocate that patients who are seen in the clinical setting should be treated aggressively. Half-dose PDT is currently the treatment of choice. It has been found that the cure rate of acute mesophoria is about 95% and that of chronic mesophoria is about 85% after active treatment, therefore, in clinical practice, we should also actively communicate with patients before treatment, not all patients can be completely cured.