When it comes to eye diseases, many people think of “glaucoma and cataract”, people are not unfamiliar with the word glaucoma, but they may not know much about what kind of eye disease it is and why they should pay attention to it. So, what is glaucoma? Glaucoma is an irreversible, blinding eye disease caused by pressure in the eye (intraocular pressure) that exceeds what the optic nerve can tolerate, resulting in impaired visual function. The eye, like a tire, must have a certain amount of pressure inside it to work properly, but too much pressure and the tire will blow out and the eye tissue will be damaged. Whether a disease should be taken seriously by society and individuals depends on whether the disease has a high prevalence and whether it is harmful. Glaucoma meets exactly these two requirements. First, the prevalence of glaucoma is high, and it is currently ranked internationally as the second most blinding eye disease after cataracts. It can occur at any age, but is commonly seen in middle-aged and older adults. According to some data, the prevalence of glaucoma is about 1% in the overall population and about 3% in people over 45 years of age, and it is conservatively estimated that there are 66 million glaucoma patients worldwide. Second, glaucoma is a blinding eye disease. If patients with glaucoma are not treated effectively, depending on the type, the affected eye can go blind in a few days or a dozen days, or in a few years or a decade. It is important to emphasize that the blindness of glaucoma is irreversible, which means that current medical technology and techniques cannot restore the sight of patients who have lost their eyesight due to glaucoma. In contrast, cataracts, the number one cause of blindness, can be treated surgically to restore visual function. In this sense, glaucoma is a much greater threat to visual function than cataracts. When we talk to newly diagnosed glaucoma patients in clinical practice, we often hear them say, “No way, my eyes are fine, my vision is 1.5, how can I have glaucoma? In fact, visual acuity is only one part of visual function, it is the clarity of our vision when we look at something. Visual function also includes another important basic component – the visual field. Visual field is the extent of what the eye can see when looking forward. In everyday life, a good field of vision is just as important as good visual acuity. Patients with a small field of vision often bump into each other because they can’t see objects around them, and they have close calls when crossing the street because they can’t see the cars coming and going on either side of them. Glaucoma begins with damage to the visual field only, which becomes smaller and smaller, and only in advanced stages does it damage vision, so it is important not to judge an eye by its vision alone. Another misunderstanding people have about glaucoma is the intraocular pressure. Many people feel that they are not glaucoma because their IOP is not high when they go to the hospital. First of all, IOP fluctuates, and one time when IOP is not high does not mean that IOP is not high; secondly, there are some glaucoma patients whose IOP is not high all the time. Therefore, the doctor will combine the IOP with other test results such as fundus, atrial angle and visual field, and if necessary, make a 24-hour IOP daily curve to determine whether the patient has glaucoma. You may ask, “Can we take steps to reduce the risk of glaucoma? Unfortunately, current technology cannot reduce the incidence of glaucoma, but it can reduce the rate of glaucoma blindness. Our country is technologically advanced in the clinical treatment of glaucoma and is in step with international standards. With early detection, diagnosis and treatment, the vast majority of glaucoma patients can maintain useful visual function throughout their lives. The premise of early detection of glaucoma is that each of us can understand and pay attention to the dangers of glaucoma.