Diabetes is a chronic disease for which there is no complete cure, and as the disease progresses, many people develop various complications. In fact, the complications of diabetes are more frightening to patients than diabetes itself, including fundopathy. Many diabetic patients think of coming to the ophthalmology examination only when they experience significant vision loss, only to find diabetic retinopathy, which has involved the macular area of the fundus and developed macular edema. The macula is the most sensitive part of the retina to light and the central area of vision, so once edema occurs, it can cause a significant loss of vision. How does diabetic macular edema occur? Diabetic macular edema is actually a manifestation of diabetic retinopathy (abbreviated as: glucose retina). If a diabetic patient does not have diabetic retinopathy, macular edema cannot occur. So how exactly does macular edema develop? Generally speaking, because diabetic patients are in a state of high blood sugar for a long time, the vascular permeability of the retina and choroid of the eye increases, and the water molecules and some protein components in the blood easily penetrate through the damaged vascular walls and gather in the macula to form edema. The reason why the macula is prone to edema is that it is the center of visual formation, with dense photoreceptor cells and high oxygen demand, therefore, once the metabolism is abnormal, the macula is more sensitive than other parts of the retina and more prone to edema. Does diabetic macular edema occur in all patients with glucose retina? No. There are two important reasons for vision loss in patients with glucose retina. One is the development of neovascularization during the proliferative phase of the glucose retina, resulting in massive vitreous or retinal hemorrhage; the other very important reason is the development of macular edema. However, it is not certain that macular edema will occur if you have glycoplasmic reticulum. Generally, about 30% of patients in the non-proliferative phase will develop macular edema, while patients in the proliferative phase of glycoplasmic reticulum have a significantly higher chance of macular edema than in the non-proliferative phase due to severe retinal vascular damage, and more than 80% of patients have macular edema of different degrees. What will patients show when they have diabetic macular edema? Once the macular edema occurs, the most important manifestation is the obvious loss of vision, this vision loss will not be yesterday’s vision was quite good, today can not see, but gradually decline, generally speaking, within a few months the patient will obviously feel the process of vision loss. If left untreated, vision will get worse and worse and may fall below 0.1, but it is not completely invisible. Generally, diabetic retinopathy is in non-proliferative stage with macular edema, which is mainly manifested as poor central vision. Patients often have trouble seeing where they want to see, while peripheral vision is relatively good, that is, they can still see clearly with afterglow. In addition, patients may also experience distortion and bending of vision, such as seeing straight objects become curved. It is worth noting that the majority of elderly people with glycoplegia are often combined with hypertension and hyperlipidemia, which can easily form thrombosis causing other retinal vascular diseases such as central retinal vein obstruction, and if these factors are present, they are more likely to develop macular edema and to a greater extent. In addition, the elderly are often accompanied by cataracts at the same time. As cataracts worsen, the fundus becomes increasingly difficult to see, which directly affects the examination of fundus lesions. Therefore, it is recommended that diabetic patients, especially those who have been diagnosed with glucose network, must follow medical advice to have regular eye examinations to achieve early detection and treatment.