Glaucoma is a chronic, progressive, irreversible optic neuropathy. When you hear this, many people will retort, what about acute closed-angle glaucoma? Is this also chronic? The answer is that glaucoma has acute attacks, but the disease is still a chronic disease, because all patients with acute attacks have some chronic causes, such as structural narrowing of the atrial angle, and treatment after the attack, etc. This is a chronic process, so the so-called acute closed angle glaucoma is actually a chronic disease. There are several ways to classify glaucoma. From whether the atrial angle is open or not, glaucoma is divided into closed-angle glaucoma and open-angle glaucoma. Of these, open-angle glaucoma accounts for the majority of glaucoma. This is an insidious disease, which is not painful and is known as the “thief of vision”, that is, the patient’s vision is damaged unknowingly, and when it is finally discovered, many of them are in advanced stages. In addition, most of the patients are elderly people who have cataracts and other problems and take it for granted that their vision is poor. In addition, most of them like to “delay” the disease and do not see a doctor until the last minute, which further aggravates the progress of the disease, resulting in doctors “unable to help” and misses the opportunity to treat. So, how can glaucoma be detected early? We know that the classic tests include visual acuity, ophthalmologic examination (including atrial angle and fundus), visual field examination, OCT (optical coherence tomography) to check the thickness of the optic nerve fiber layer, and now there is a new test: MRI. People will ask: how is this a new test, it has been available for a long time? Yes, this is an old test, but in recent years, more and more literature has reported that the optic nerve, including the optic cortex, is abnormal in patients with glaucoma, not only because of the thinning of the optic nerve fiber layer, but also because of the high intraocular pressure that affects axoplasmic transport and causes lesions in the superior neurons. There are many patients who have “normal IOP glaucoma”. Why do you have glaucoma when your IOP is normal? There is a structure on the optic papilla called the “sieve plate”, which is the pathway of nerve fibers to the brain center. In normal eyes, there is a pressure difference between intraocular pressure and intracranial pressure, i.e., intraocular pressure > intracranial pressure, and the difference is about 4 mmHg, which is the largest pressure difference exposed to the nerve tissue in the body, which is really a “big duck pear” for the nerve tissue, and the nerve tissue is not renewable, once the pressure is broken, it is impossible to recover. The nerve tissue is non-renewable and once it is crushed, it cannot be recovered. Therefore, many studies have found that patients with normal IOP glaucoma have low intracranial pressure and the pressure difference between IOP and intracranial pressure is too large, resulting in nerve damage and thus vision impairment. Some of these changes can be detected by MRI (magnetic resonance imaging), which may even predict the prognosis for treatment, offering new hope for glaucoma patients. MRI is now being used in individual large general hospitals to examine patients with glaucoma, especially for early diagnosis of glaucoma with normal eye pressure. As the technology continues to mature and progress, it is believed that MRI will soon become a routine screening test for glaucoma.