EyeWorld Asia-Pacific March 2017 Issue

EWAP SECONDARY FEATURE 29 March 2017 Views from Asia-Pacific YAO Ke, MD Professor, Eye Institute of Zhejiang University Eye Center, Second Affiliated Hospital of Zhejiang University, College of Medicine 88 Jiefang Road, Hangzhou, 310009, China Tel. no. +86-571-87783897 Fax no. +86-571-87783897 xlren@zju.edu.cn I n Asia, especially in China, PACG is a common type of glaucoma. Every year, we perform over 8,000 cases of laser peripheral iridotomy (LPI) and hundreds of phacomulsification procedures on patients with PAC or PACG in our eye center. Since we make 2.2-mm clear corneal incisions in modern phacomulsification, some surgeons think that trabeculectomy can also be done safely in case of failed pressure control after lens extraction. Dr. Brown’s view on treating PAC or PACG with lens removal is an interesting topic. However, whether lens extraction can be considered as the first-line treatment in PACG is worthy of discussion. Our clinical practice showed that whether lens extraction could open the anterior chamber angle depends on the duration and severity of peripheral anterior synechiae (PAS). It is effective in PAC especially in those patients who have less than 180 degrees of PAS. But in serious chronic PAC or PACG, even after phacomulsification with goniosynethialysis, PAS may recur. IOP may rise subsequently because of trabecular meshwork pigmentation due to long-term synechiae. Primary consensus of treatment in our eye center is as follows: 1. Patients who have narrow angles or less than 180 degrees PAS with clear lens will be treated with LPI. Phacomulsification with intraocular lens implantation will be considered earlier if the lens is with local opacity. 2. In patients with PAS less than 270 degrees, if the IOP is less than 30 mmHg and can be controlled by medicine, we will choose phacomulsification with goniosynethialysis. 3. When the anterior chamber angle is completely closed and the IOP is greater than 30 mmHg, we will recommend cataract surgery combined with trabeculectomy. If the anterior chamber is extremely shallow, the success rate of simple trabeculectomy is not high, and there is a high incidence of postoperative cataract. Moreover, phacoemulsification to treat PAC or PACG can be technically challenging due to a shallow anterior chamber, poor mydriasis, posterior synechiae adherent to the lens, and weakness of the zonular fibers, etc. It is best for the procedure to be performed by a highly experienced surgeon to avoid severe complications. Editors’ note: Dr. Yao declared no relevant financial interests. are no studies on the role of clear lens extraction in treating angle closure, however, if the anterior segment anatomy is the problem, and it frequently is, removing a clear lens may have the same positive effects as removing a cloudy lens.” In a review of studies surrounding lens extraction in PACG, 2 Dr. Brown demonstrated a strong body of evidence in favor of cataract surgery for angle-closure patients to reduce IOP and dramatically reduce the future risk of IOP spikes and acute attacks. Cataract surgery was found to be a more effective treatment for an attack of acute primary angle closure than laser iridotomy. It also demonstrated better outcomes when compared to phaco trabeculectomy, which showed a higher complication rate than phacoemulsification alone. He showed evidence that described an increased risk of 50% for requiring cataract surgery in patients undergoing trabeculectomy, with the added risk of the subsequent cataract surgery, threatened function of the bleb, and loss of any benefit to the IOP of removing the lens primarily. Although Dr. Brown combines goniosynechialysis with clear lens extraction to help to reduce IOP, no studies have compared the risks and benefits of phacoemulsification with goniolysis using phaco alone. In his practice, Dr. Brown has seen many cases where pressures have normalized with cataract surgery alone. A classic case in point was a 45-year-old patient with PACG and a clear lens, who had undergone LPI and iridoplasty but still had IOP of more than 30 mmHg and was on maximum dosages of medications. The patient began showing increased optic nerve cupping, even though the visual field was full. In the absence of cataract, many surgeons would have recommended a trabeculectomy. However, after many consultations with the patient and another specialist, who recommended a trabeculectomy, the patient opted for clear lens extraction. The 5-year results show normal IOP and the patient is medication-free. Dr. Brown has also performed clear lens extractions for angle closure issues in more than 20 patients who had small fixed pupils from previous pilocarpine use and iris epithelium adherence to the anterior lens surface from repeated laser iridoplasty in unsuccessful attempts to pull the iris out of the angle. The patients were highly hyperopic (up to +18) with short eyes and very shallow chambers, some requiring pars plana vitrectomy to have enough anterior chamber room for surgery. These risk factors make cataract surgery/ clear lens extraction in this group very difficult, and Dr. Brown thinks that performing early lens removal would help avoid unnecessary complications and reduce the future risk from pressure damage. He said, “Predicting which angle- closure patients will benefit from lens removal—whether clear or cataractous—remains uncertain. Concerns about clear lens extraction generating high volumes of unnecessary surgery continued on page 34