In layman’s terms, glaucoma encompasses a large group of diseases that can be primary, secondary to other eye diseases, or even secondary to systemic diseases. From a medical point of view, glaucoma is a group of diseases closely related to pathologically elevated intraocular pressure, characterized by optic nerve atrophy and visual field defects. Glaucoma has a relatively high incidence of about 1% of the overall population and is currently the second most blinding eye disease in the world after cataracts, and is more serious than cataracts in terms of harm. This is because the vast majority of cataracts can be restored through surgery, whereas if glaucoma causes blindness once the optic nerve is damaged, it cannot be reversed. The number of people with glaucoma in China is about 5-6 million, and the number of people blinded by glaucoma is about 400,000-500,000. One of the main characteristics of glaucoma is the insidious nature of its onset. Except for a few patients who have acute attacks with symptoms such as eye redness, eye rise, eye pain and blurred vision, the vast majority of patients with early glaucoma do not have any prominent symptoms. In outpatient treatment, many patients just have the usual occasional eye pain and get better after a day or two of rest, and when they come to check their eyes in acute grand mal or by chance, they are found to have reached a more serious level. Some data show that even in Europe and the United States, where medical technology is advanced, at least half of glaucoma patients do not know that they have glaucoma. In the early stages of glaucoma, many patients can have very good distance vision, and as the disease progresses, the patient’s visual damage gradually worsens. At this point, although the ophthalmologist has the means to detect the visual deficit, the patient may remain unaware of the condition, and this is the danger of glaucoma: by the time the patient becomes aware of the visual field deficit on his or her own, it has often reached a stage of severe damage. Patients may be grateful that their vision is unaffected and let their guard down. Unbeknownst to the patient, the visual field defect may be very severe even if the central vision is 1.0. Although the cause of glaucoma has not been clearly identified to date, the disease can be controlled through treatment. There are many eye medications available for glaucoma, and most patients can control their IOP at an ideal level with medication. It is important to emphasize that glaucoma, like hypertension, coronary heart disease, diabetes and other well-known systemic diseases, is a lifelong condition that must be treated for life as long as it is present. The few patients who cannot control their IOP with medications may require surgery. It is worth mentioning that many elderly patients, can be treated with cataract surgery to solve the glaucoma problem, which can kill two birds with one stone. Once you have persistent and recurrent eye redness, even to the point of eye swelling and eye pain, it is important to seek prompt medical attention.