Diabetes, as an endocrine disease, may not sound like it has much to do with the eyes. As you know, the greatest danger of diabetes is the many chronic complications it causes. The eye is a common site for chronic complications of diabetes, whether it is the eyelid, cornea, conjunctiva, lens, retina, or optic nerve. Among them, diabetic retinopathy (commonly known as “glycosuria”) has become one of the three major blindness-causing eye diseases announced by the World Health Organization. With the development of our national economy and the improvement of people’s living standards, China has quietly become a “big country” with diabetes. According to statistics, there were 382 million diabetics worldwide in 2013, and more than 100 million in China, with almost one in every three to four diabetics coming from China. Compared to the other two types of blinding eye diseases: age-related macular degeneration and glaucoma, the population affected by glycoretinopathy is mainly the young and middle-aged working population, and the serious social burden of the disease caused by the huge number of people with the disease is self-evident. The scary thing about glycoretinopathy is that its onset is silent. In the early stages of the disease, it goes unnoticed because the patient’s vision is not affected or is not seriously affected. However, once the disease has progressed to a stage where vision is impaired, the disease is usually close to or at an advanced stage, and the best stage of intervention is missed, and the damage to vision is irreversible. Therefore, it is not an exaggeration to call diabetes the invisible “killer” of vision. To understand this disease, we must first understand what the retina is: If we compare the eye to a camera, the retina is the equivalent of the film of the camera, which is the important part that perceives vision and translates it into the brain. Just as you can’t get a good picture without a good film, you can’t get a clear image without a healthy retina. The retina is made up of photoreceptor cells, nerve tissue, etc. The structure is extremely complex and cannot yet be replaced by transplantation or artificial means like the cornea or lens. How does diabetes cause damage to the retina? It is mainly due to the hyperglycemic state caused by the disease. Hyperglycemia first causes damage to the microvasculature in the retina, resulting in insufficient blood supply to the retinal tissue. The resulting ischemia and hypoxia cause damage to the retina, which in turn causes the growth of abnormal new blood vessels, eventually leading to hemorrhage, fibrous tissue proliferation, and tractional retinal detachment; just like the distortion, rupture, and defacement of a camera film, resulting in complete loss of vision. The course of glucose retinal disease can be divided into early, intermediate, and late stages. For the majority of patients in the early stage, efforts to control blood sugar can keep the disease “quiet” and not progress. For patients in the middle stage, in addition to active blood glucose control, laser treatment can still be more effective in stopping the progression of the disease. For patients with advanced disease, surgery is often required to stop further vision loss, but the damage to vision is usually very severe and irreversible. Early diagnosis and treatment are therefore very important. How can this “invisible killer” be detected early? It is recommended that people over the age of 45 or those at high risk should have regular medical checkups. Once diabetes is diagnosed, in addition to actively controlling blood sugar, patients should have an early eye examination, especially a retinal examination after dilated pupils, to detect early lesions in time so that ophthalmologists can assist in intervention and treatment. In addition, as diabetes progresses, the chance of eye complications increases year by year, so regular follow-up eye examinations are also necessary. Diabetic retinopathy is preventable and treatable, but the key lies in people’s awareness of the disease. We believe that with the joint efforts of doctors and patients, this invisible “killer” will eventually be put in a cage and will not be allowed to “do evil” to harm the light of human beings.