Posterior capsulotomy

With the increasing popularity of extracapsular cataract extraction, the treatment of posterior capsule opacity has become one of the most important clinical topics. According to reports, after 2 to 3 years of follow-up of extracapsular cataract extraction, 28 to 43% of posterior capsule opacity occurred, requiring posterior capsule capsulotomy. The so-called fibrous membrane, grayish-white or ceramic-like opacity, which may occur in the early postoperative period, may be related to intraoperative residual lens cortex; and several months to several years after surgery, it is related to the proliferation and movement of lens epithelial cells, and is special. The appearance of the vesicles is called Elschnig beads. Pathological examination revealed that the proliferating epithelial cells originated from the anterior capsule fragments. This fact also proves that post-capsular polishing during surgery is not conducive to delayed capsular opacity. The extensive anterior capsule incision allows the anterior capsule stump to be further away from the visual axis, helping to delay the formation of a proliferative membrane in the visual axis. Posterior capsule wrinkles are a common combination after intraocular lens implantation. Most of them occur after posterior chamber intraocular lens implantation, and the wrinkles are consistent with the meridian direction of the lens. If it does not combine turbidity, it may not affect vision. However, the wider undulating wrinkles can also cause subjective symptoms such as visual distortion and flashing of the patient, and even a significant decrease in visual acuity. Postoperative inflammatory reaction is heavier or longer, or there are more residual cortex in the operation, which can cause iris capsule adhesion. The reactive pigment epithelium proliferates and migrates to the posterior capsule surface, forming dense turbidity, which will seriously affect vision. This can also occur after the postoperative anterior chamber hemorrhage is absorbed. Treating diseases: cataracts, surgical procedures Anesthesia and position Under normal circumstances, no anesthesia is required: if a contact lens is used, a special contact lens should be placed after topical anesthesia; in extreme cases, such as nystagmus, post-ocular anesthesia can be performed. Surgical procedure If the pupil is large enough, it does not need to be dilated; if the pupil is small, it is estimated that it will affect the operation, then the pupil is properly dispersed before treatment. However, due to some circumstances affecting the shape and size of the pupil, especially after dilation, the visual axis area and surrounding reference signs must be determined before dilation. Start with the minimum energy and gradually increase until the cutting effect occurs. For simple posterior capsule opacity, a single pulse energy of 1 to 2 mJ is suitable. If the energy is too large, although the cutting effect is more significant, the possibility of complications is also greater. The cutting generally starts from the center or the upper 12 o'clock clock position, and then expands downward, inward, and outward in a corrugated manner to make a circular cut. Avoid open-end circular incision because it can produce large pieces of debris to be retained in the anterior chamber, causing severe postoperative reactions. In the presence of a posterior intraocular lens, the patient must be carefully examined before treatment to determine the distance between the posterior surface of the lens and the posterior capsule to predict possible problems during treatment. Accurate focus in treatment, the use of small energy is an important measure to avoid intraocular lens damage. In addition, treatment from the top can also reduce the chance of damage to the posterior surface of the lens in the visual axis due to undue energy. Another way to reduce lens damage is to focus on the back of the capsule (in the vitreous), but a much larger amount of energy must be used to generate a sufficiently strong shock wave. The size of the posterior capsule incision should be determined on a case-by-case basis. The dense and completely turbid posterior capsule, although a small diameter cut, can obtain clear vision; for translucent, or only the posterior capsule fold, small diameter cut, will be cut around The translucent area interferes with the visual prognosis. At this time, it is appropriate to make a cut that is about the size of the pupil.