EyeWorld Asia-Pacific September 2014 Issue

September 2014 19 EWAP GLAUCOMA 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./Fax no. +86-571-87783897 xlren@zju.edu.cn T he prevalence of angle closure glaucoma (ACG) varies greatly by ethnicity and it was more common among Asian populations with the rate about 1.5-2.5%. 1,2 Primary angle-closure glaucoma (PACG) was more than primary open-angle glaucoma (POAG) in the Chinese population and its prevalence was significantly higher in older people. In our hospital we often see adults aged 50 years old with intumescent cataract having narrow anterior chamber anatomy and can be found to have narrow or partial closure of the angle using ultrasound biomicroscopy (UBM). We usually perform a laser peripheral iridotomy (LPI) which is quick and relatively well-tolerated in these patients whose peripheral anterior synechiae are no more than 180 degrees to relieve the pupillary block. Combined cataract and glaucoma surgery can achieve long-term glaucoma control with a single operation and protect against the IOP rise that may complicate cataract surgery alone. According to the AAO Preferred Practice Pattern Guidelines Cataract in the Adult Eye 2011 , the primary indication for cataract surgery is visual function that no longer meets the patient’s needs and for which cataract surgery provides a reasonable likelihood of improved vision 3 . Only clear lens extraction in ACG patients needs a broad discussion. Cataract extraction alone can produce an IOP reduction in narrow anterior chamber eyes, but the effect in eyes with PACG with more than 180 degrees angle closure requires more clinical research and trials. The decision of whether to do the goniosynechialysis is made by the ophthalmologist after discussing the risks and benefits. I would perform goniosynechialysis combined with cataract surgery if there is more than 180 degrees and no more than 270 degrees of peripheral anterior synechiae which does not have a very long history. It is worth asking whether to try cataract surgery first in ACG patients with particularly high pressures who may need a trabeculectomy. I can’t agree with this viewpoint entirely, because for chronic angle-closure glaucoma patients or later stage glaucoma patients, cataract surgery is insufficient to prevent glaucomatous progression and follow-up trabeculectomy is necessary and inevitable. Trabeculectomy technology on the other hand is mature and reliable. Phacotrabeculectomy has better IOP control compared with single cataract surgery and it is not a complicated procedure. Phacotrabeculectomy may decrease the occurrence of postoperative shallow anterior chamber, prevent quickly increasing IOP after a single cataract operation, and protect the advanced glaucoma patients’ residual vision. References 1. He M, Foster PJ, Ge J, et al. Prevalence and clinical characteristics of glaucoma in adult Chinese: a population-based study in Liwan District, Guangzhou. Invest Ophthalmol Vis Sci . 2006;47:2782–2788. 2. Casson RJ, Newland HS, Muecke J. Prevalence of glaucoma in rural Myanmar: the Meiktila Eye Study. Br J Ophthalmol. 2007;91:710–714. 3. American Academy of Ophthalmology Cataract and Anterior Segment Panel. Preferred Practice Pattern Guidelines. Cataract in the Adult Eye . San Francisco, CA: American Academy of Ophthalmology; 2011. Available at: www.aao.org/ppp Editors’ note: Dr. Yao has no financial interests related to his comments. Edgar U. LEUENBERGER, MD, DPBO Associate Professor, Asian Eye Institute and University of the East RM College of Medicine 9F Phinma Plaza, Rockwell Center, Makati City, Philippines Tel. no. +632-8982020 Fax no. +632-8982002 EUL@asianeyeinstitute.com A quick way to screen for angle closure is to check the limbal chamber depth at the slitlamp followed by gonioscopy with and without indentation. When correlated with the presence or absence of iridotrabecular (IT) contact, peripheral anterior synechiae (PAS), high IOP, and glaucomatous optic neuropathy (GON), patients can then be classified into four groups: primary angle closure suspects (PACS), primary angle closure (PAC), primary angle closure glaucoma (PACG), and acute angle closure crisis (AACC). Furthermore, the use of anterior segment imaging devices in these groups of patients allows the clinician to assess anterior chamber depth, lens vault, iris thickness, IT contact, and existence of plateau iris. The body of information obtained from manual and automated instrumentation can then be used to plan the most effective treatment strategy, evaluate outcomes, and educate the patient. Although removing the lens addresses a major part of the mechanism of angle closure, treatment should be based on what is safest and most cost-effective for the patient. Advances in cataract extraction have made an invasive procedure easier and safer for the patient and the surgeon. In spite of this, one should consider the risk of sight- threatening complications such as infection, retinal detachment, and corneal or macular edema. In PACS where IT contact is present in at least 180 degrees, no PAS, IOP and optic nerves are normal, visual acuity and lenses are clear, and the patient is asymptomatic, I would observe and do serial gonioscopy. Anterior segment OCT may be helpful in documenting pupillary block. In patients who complain of browaches and headaches or who require frequent dilation for retinal examinations, I do not hesitate to perform a laser iridotomy, and iridoplasty as needed. If the lens opacity is significant, then cataract surgery is justified. In PAC where IT contact is present in at least 180 degrees, with PAS or elevated IOP, and normal optic nerves, more aggressive efforts should be made at preventing progression to PACG. In this scenario, laser iridotomy and iridoplasty are my first line of treatment. If IOP continues to be elevated, or in the presence of visually significant cataract, lens extraction may be performed. In medically uncontrolled PACG where PAS, high IOP, and GON are present, cataract surgery may be beneficial. This approach has been demonstrated to be as effective as filtering procedures and avoids the complications of trabeculectomy. Medical treatment and laser iridoplasty are established primary methods to control the high IOP and patient discomfort associated with AACC. Thereafter, cataract surgery can be performed as the definitive procedure. In sum, modern cataract surgery has allowed investigators to safely explore its usefulness in the treatment of angle closure disease. I look forward to the results of large worldwide clinical trials that would help update clinical practice guidelines. Editors’ note: Dr. Leuenberger has no financial interests related to his comments.