Mature cataracts last too long, and after several years there is a continuous loss of water in the lens, a reduction in volume, wrinkling of the capsule membrane, and irregular white spots and cholesterol crystals. The crystal fibers decompose and liquefy, and the milky white, brownish-yellow nucleus of the lens sinks below the capsular bag and can move with position, called Morgagnian cataract. The nucleus can move within the capsular bag due to the crumpling of the capsule membrane, making it particularly difficult to rupture the capsule. When the anterior capsule is punctured, the emulsified cortex overflows and only the brownish nucleus remains in the capsule bag, and the anterior and posterior capsule membranes are tightly packed. When the capsule is broken, the posterior capsule membrane is easily damaged or the broken capsule is incomplete, which affects the surgical operation or the IOL cannot be implanted, resulting in surgical failure. It is a special form of cataract, which is rarely seen in patients with overripe cataract, and is only encountered more often in the process of blindness prevention and treatment. Key points of surgical operation: ① Adequate dilatation of the pupil before surgery to facilitate observation of the capsular bag tension. If the pupil is not sufficiently dilated before surgery, low concentration and small dose of epinephrine hydrochloride can be injected into the anterior chamber before breaking the capsule, and the pupil should be sufficiently dilated before surgery. The incision tunnel should be slightly longer should be made horizontal 5L×3.5mm, easy to watertight; the inner mouth should be wider than the outer mouth. When piercing the anterior capsule, do not enlarge the capsule opening to avoid overflow of emulsified cortex from the capsule opening, clouding of the anterior chamber, unclear operation field, and affecting the operation; the starting point of breaking the capsule should be located in the anterior capsule near the upper edge of the crystal nucleus, so that it is easy to pry up the upper edge of the nucleus with the viscoelastic needle, inject viscoelastic into the subnuclear capsule bag, prop up the capsule bag, and the nucleus floats tightly against the anterior capsule membrane until the capsule membrane has certain tension, which is easy to break the capsule operation and simplify the steps of prying the nucleus after breaking the capsule. When prying the nucleus while injecting viscoelastic, the needle should not be deep, especially when the emulsified cortex is overflowing, we should be more careful, maybe at this time the nucleus and posterior capsule have been tightly adhered to easily lead to posterior capsule rupture but not detected. The microscope should be magnified to about 10 times, and the anterior capsule membrane should be cut in an arc near the upper and lower edge of the crystal nucleus, the capsule-breaking needle should be sharp, and the technique should be gentle and smooth to avoid jagged edges, and then the capsule membrane should be cut on the left and right sides of the arc-shaped mouth with arc-shaped capsule scissors, paying attention to the articulation with the end of the arc to form a round-like capsule mouth finally. Intraoperative accidents and treatment: ① When breaking the capsule, the milky white liquefied cortex overflows in the anterior chamber, this so-called intraoperative “smoke” phenomenon affects the operator’s vision and makes the operation more difficult, if the amount is small, the milky white cortex can be pushed to the peripheral exposure operation area with viscoelastic; if the amount of overflowing cortex is large, the emulsified cortex can be rinsed clean first and then injected with viscoelastic to fill up the sac, which requires more viscoelastic. If the curved scribing of the bursa cannot be successfully operated, the bursa can be broken by opening the can instead. The main reason is that the capsule is shallow and the pressure in the posterior chamber is high. The capsule can be replenished with viscoelastic and the viscoelastic can be injected into the optical surface of the IOL to make it sink by the gravity of the viscoelastic. into the capsular bag. If the postoperative incision is not watertight enough, a small amount of irrigation fluid can be injected into the corneal stroma on both sides of the incision to make the stroma edematous and increase the tension of the incision to achieve complete watertightness without sutures, which is an effective method to reduce postoperative astigmatism. Advantages of small incision: less damage to the incision tissue and fewer complications. Both spherical conjunctival and corneoscleral incisions are smaller than conventional surgery, and the tunneling incision crosses the atrial angle, hardly hurting the atrial angle tissue, therefore, the surgical injury is reduced accordingly, and the postoperative spherical conjunctival congestion is significantly reduced. The larger the incision, the greater the surgical corneal astigmatism. The size of the incision is proportional to the size of the surgical astigmatism. The large incision is generally 10-12L corneoscleral margin conventional incision, small incision is generally below 6L, this group is horizontal 5L incision and does not meet the closure, postoperative astigmatism is significantly reduced. The advantages of this group of capsulorhexis: ①The capsulorhexis technique is to restore the original tension of the capsular membrane under the support of viscoelastic, and to form a circular-like capsular opening by arc-shaped scratching of the capsular membrane and arc-shaped cutting of the capsular membrane, which is better than the can-opening capsulorhexis and second only to the continuous circular tearing of the capsular, with a smoother capsule opening, which can produce a certain tension and has the ability to resist adsorption and rupture; at the same time, because of its smooth edge, it avoids the iris and other tissues such as anterior capsule The smooth edge avoids iris pigment detachment and even iris reaction due to friction between the broken edge, cortex, and IOL; because there is no broken strip floating in the anterior chamber produced by the open-can type capsulotomy, it is not easy to form adhesions or traction with the iris, which reduces the formation of IOL anterior membrane and is the key to forming a round pupil and avoiding IOL entrapment by the pupil; the round-like row of capsulorhexis allows IOL to be easily implanted into the capsular bag without easily producing deviation and It reduces the astigmatism caused by the deviation of the crystal position. The successful injection of viscoelastic into the nucleus following the puncture of the anterior capsule prior to capsulorrhexis is one of the key steps in perimetric cataract surgery. The capsule bag is full, making it easy to break the capsule, and the viscoelastic separates the anterior and posterior capsule membranes, greatly reducing the chance of posterior capsule rupture and ensuring the implantation of IOL in the capsule bag, which is more in line with the physiological requirements and greatly improving the visual quality. In this group, there was no case of posterior capsule rupture, and all IOLs were implanted in the capsule, while in the control group, there were 4 cases of rupture, 2 cases of ciliary sulcus implantation, and 2 cases of abandonment of implantation. In this group, the viscoelastic was injected into the posterior part of the nucleus at one time, and the nucleus was floated against the anterior capsule membrane, with the round-like capsule opening slightly larger than the diameter of the nucleus. This simplifies the procedure and shortens the operation time, thus gaining time for cataract restoration.