What is glaucoma? Glaucoma is a common and difficult eye disease that has a rapid onset, is very dangerous and can lead to blindness at any time. It threatens the vision of one in fifty adults over the age of thirty-five. It is characterized by an intermittent or persistent increase in intraocular pressure that exceeds the tolerable level of the eye, causing damage to all parts of the eye and visual function and eventually leading to irrecoverable blindness. Complete blindness can occur in 24-48 hours during acute attacks. Glaucoma is a bilaterality and can occur in both eyes at the same time or in one eye, followed by blindness in both eyes. Therefore, early examination, diagnosis and treatment of glaucoma is the key to prevent optic nerve damage and blindness. There are four main types of glaucoma: congenital glaucoma, primary glaucoma, secondary glaucoma, and mixed glaucoma. The clinical manifestations and characteristics of each type of glaucoma vary, the most common being primary glaucoma. What are the manifestations of the onset of glaucoma? The onset of the disease is rapid, manifested by severe pain in the side of the head of the affected eye, redness of the eye, and the typical symptoms of sudden loss of vision or the phenomenon of rainbow vision (looking at lights like a rainbow). The pain radiates around the eye orbit, sinuses, ear roots, teeth, etc.; the eye pressure rises rapidly and the eye is hard, often causing nausea, vomiting, sweating, etc. Patients often go to the neurology department because of the severe headache, while some patients wait until the gastroenterology department for nausea and vomiting and lose their vision because the best treatment period is delayed. Glaucoma mostly strikes in the evening and is easily triggered by emotional excitement. Long hours of reading, fatigue and pain are also common triggers for the disease, so patients with glaucoma should pay attention to the above-mentioned conditions and go to the hospital immediately if they have an acute attack. There are also some types of glaucoma that are not accompanied by eye pain. For these types of glaucoma, the risk is greater, and they are often found to be late, and some are even blind. Glaucoma also occurs easily in patients with high myopia, diabetes, hypertension, and a family history of glaucoma.