What is glaucoma? Glaucoma is the number one blindness-causing eye disease worldwide and is therefore highly valued by ophthalmologists and eye disease researchers. Glaucoma is a group of eye diseases that have pathologically high eye pressure and lead to optic nerve atrophy and visual field defects. Why is it important to check IOP in glaucoma patients? Clinicians find that most glaucoma patients have elevated intraocular pressure (IOP). But the relationship between IOP and glaucoma is again somewhat complicated. Statistically, the normal IOP range is 10-21 mmHg, but clinically, any IOP that can cause tissue damage (mainly to the optic nerve) is harmful even if it does not exceed 21 mmHg, as in “normal IOP glaucoma”. Conversely, IOPs above this range that do not cause any damage to the eye cannot be diagnosed as glaucoma, such as “hypertensive glaucoma”. Therefore, glaucoma is not a simple eye disease, but a syndrome, and the diagnosis of glaucoma should be a combination of several indicators: fundus examination, OCT, visual field and intraocular pressure, rather than a single “normal” IOP or not. What is 24h IOP? Because IOP, like blood pressure, fluctuates from moment to moment, a single normal IOP is not indicative of a problem. Researchers have found that half of all glaucoma patients have high IOP between 1:00 a.m. and 7:00 a.m., so a 24-hour IOP measurement is important for both diagnosis and treatment of glaucoma. Based on the highest and fluctuating values of IOP, the doctor can decide whether to treat it surgically or with medication; and choose the best time to do so. How to make a clear diagnosis? In China, there are 5 million glaucoma patients, primary closed-angle glaucoma and primary open-angle glaucoma are the most common. If a patient’s IOP is higher than 30 mmHg, the diagnosis is straightforward, but clinically, many patients have IOP between 21-30. Whether it is glaucoma or not will require detailed clinical examination and longer clinical observation and follow-up. The first step is visual field examination. Visual field examination is the ‘gold standard’ for the diagnosis of glaucoma, but abnormalities in the visual field usually appear late, and it has been reported that 40-50% of the optic nerve cells die before the local visual field becomes defective, so we often use dynamic follow-up observation with OCT to detect the problem early.OCT (optical correlation tomography), can objectively OCT (optical correlation tomography) can objectively examine whether the cup-to-disc ratio is enlarged and whether the thickness of the retinal nerve layer is compromised. The concept of the cup-to-disc ratio is as follows: the nerves in the eye converge through the optic disc and travel to the brain. The optic disc is like a hole in the wall of the eye, filled with the optic nerve. Usually the optic disc is not filled, during which there is a space left called the optic cup, which is the cup-to-disc ratio. Therefore, it is easy to understand that if the optic nerve dies, the optic cup becomes larger and the cup-to-disc ratio increases. The normal value of the cup-to-disc ratio is <= 0.3, and if it is greater than 0.6 we usually consider that the patient's optic nerve has died, so it is time to look for the cause. Retinal thickness, a medical term that is easy to understand, is the thinning of the retina if the optic nerve is dead. When we examine patients with a thinning retina or a larger cup-to-disc ratio, we put these patients on the follow-up observation team. We usually ask the patient to keep the OCT results from this year and wait until a year later to test again and compare the 2 results to determine if the patient's optic nerve continues to thin and to determine if the patient has glaucoma. The longer follow-up time is due to the fact that glaucoma is a chronic disease that does not change significantly within 1-2 months, so one must wait a long time and then compare the observations. However, patients do not have to worry that the condition will not deteriorate drastically in 1 year, with problems such as blindness. Glaucoma treatment currently focuses on reducing intraocular pressure and optic nerve protection treatment. The main methods of treatment are surgery and medication. If the IOP is high, for example, above 30 mmHg, surgery is usually used; if it is below 30 mmHg, medication is usually used, but of course this is also related to the patient's condition. Precautions: Patients with closed-angle glaucoma: Avoid working, studying and living in a dim environment for a long time. 1, avoid lowering the head for too long, such as reading books, playing mahjong, cross-stitching, etc. 2, avoid drinking a lot of water (a lot means more than 500ml) can be small amount of water many times. At the same time all glaucoma patients should pay attention to keep: emotional optimism, avoid dramatic emotional changes; instruct immediate relatives to check regularly; insist on regular contact with doctors, follow-up checkups, etc.