This question involves how does closed-angle glaucoma develop? In other words, how does the atrial angle close? The eye is made up of the wall and the contents of the eye, just as an egg is made up of the shell and the yolk of the egg. The black eye and the white eye that we see are the cornea and sclera of the eye wall, respectively. The anterior segment of the eye is divided into two parts, the anterior chamber and the posterior chamber, as shown in Figure A. 1 shows the anterior chamber, which has a volume of 0.2 ml, and 3 shows the posterior chamber, which has a volume of 0.06 ml. Between 1 and 2 is called the iris, and the middle of the iris is called the pupil, or what the people call the pupil, usually 3-4 mm, as shown in 2. 5 shows the lens (which is called a cataract when it is cloudy) is located at the back of the posterior chamber. The lens is posterior to the vitreous body, as shown in Figure 6. The angle between the iris and the cornea shown by the arrow in Figure A is called the atrial angle, which is open in normal people, or not narrowed or closed, and the atrial water is drained to the outside of the eye through the trabecular meshwork of this angle That said, there is a tissue in the peripheral part of the posterior chamber called the ciliary process, as shown in Figure A.4 It secretes fresh atrial water like a mountain spring every day, with a secretion volume of 2.64 ml/day, which is ten times the volume of the anterior and posterior chambers. Ten times the volume of the anterior and posterior atria. Without this secretion function, there would probably be no glaucoma, and certainly no nutrition for the eye, and no bright, vibrant eye. Fresh atrial fluid is produced every moment from the posterior chamber, passes through the pupil, enters the anterior chamber, and flows out of the eye through the trabecular meshwork, which is the normal process of atrial fluid circulation in the eye. Why is the pupil a “gateway”? It is as important as the Tongguan Pass, a major road in ancient warfare. The atrial fluid makes a 360 degree turn at this “gate”. It is precisely at this place where it is easy to block and obstruct what we call pupillary-lens block (pupillary block for short). This leads us to the pathogenesis of closed-angle glaucoma. In a normal person or patient, the atrial angle is open before the onset of the disease and the atrial fluid circulation is normal. As people age, the lens becomes cloudy, the anterior and posterior diameters become larger (thicker), or in some people with relatively small eyes or farsightedness, the lens is positioned relatively forward, so that the lens and pupil stick together, and the atrial water does not pass through this area smoothly, so the atrial water pools here, causing the pressure in the posterior chamber to increase, which in turn pushes the iris forward, causing the iris to bulge up. The bulging iris adheres to the trabecular meshwork, so the atrial angle becomes narrower, and over time the iris adheres to the trabecular meshwork, so that the atrial fluid cannot drain, and the atrial angle closes. This is shown in Figure B. This means that lens factors play an important role in the formation of closed-angle glaucoma. The process of removing the lens is the procedure for cataract ultrasound-emulsifying IOL implantation. This procedure requires perfusion pressure, and this pressure itself separates the atrial angle again. At the same time, the lens, which is about 5 mm thick, is replaced with a thin IOL of less than 1 mm, so that the pupil is completely separated from the IOL, and the pupil-lens block is completely lifted, which also, in theory, fundamentally removes the cause of glaucoma. This is why removing the cataract is a treatment for closed-angle glaucoma. It is now recognized that any patient with closed-angle glaucoma whose IOP can be controlled to normal by two IOP-lowering drugs and whose atrial angle is one-half open can be considered for treatment of closed-angle glaucoma with ultrasonic cataract removal plus IOL implantation. This procedure is a procedure to restore the internal circulation of atrial fluid, replacing the external drainage procedure of the past. This has the advantages of no discomfort such as eye grinding and eye dryness, quick recovery from surgery and short hospital stay. It also solves the problem of easy recurrence of external drainage surgery, reduces the subsequent hospitalization process for cataracts, and reduces the cost and time for patients.