This review article in the May/June issue of Clinical and Experimental Ophthalmology discusses the increasing prevalence of primary angle-closure glaucoma (PACG), and research being conducted on new screening and treatment methods for the disease. The authors say the current algorithm for treating angle closure is likely to change in the coming decade based on the results of ongoing clinical trials.
They note that prevalence among older Asian populations is high, and given global demographics, the number of people with PACG will likely increase dramatically in the coming decades. They say improvements in anterior segment imaging will help identify more people with angle closure, and clinical trials currently underway will provide evidence to support specific screening and treatment approaches.
The authors discuss several imaging methods that can assess eyes for angle closure and offer advantages over gonioscopy, which is typically used to diagnosis ACG. These methods include ultrasound biomicroscopy, anterior segment optical coherence tomography (AS-OCT), spectral domain OCT and swept source OCT. Image acquisition with these methods is rapid, more objective and reproducible, and angle images can undergo quantitative analysis, as well as storage.
Gonioscopy, on the other hand, is observer dependent and subjective, with only moderate agreement among observers. The authors say none of these new devices can presently replace conventional gonioscopy, but their use will likely increase as they become better able to produce high-resolution images of the angle and to rapidly and simultaneously scan the entire angle circumference in three dimensions.
They discuss ongoing research on the management of PACG, including the Zhongshan Angle Closure Prevention randomized controlled trial they are running in Guangzhou, China, to determine the effectiveness of laser peripheral iridotomy (LPI) as prophylaxis for primary angle-closure suspects (PACS). While there is widespread agreement and evidence that LPI prevents acute attacks in the fellow eye of those with monocular acute attacks and that nearly all patients with primary angle closure should have LPI, there is less agreement on who should have LPI in an attempt to prevent PACG among those who are PACS.
They express surprise regarding the limited evidence for the use of argon laser peripheral iridoplasty, which is widely used in Asia. They recommend more high-quality studies to assess its efficacy in clinical entities other than an acute attack.
Lens removal provides yet another approach for treating angle closure that some practitioners are already using, and it is being studied in conjunction with IOL implantation in a large, multinational randomized controlled trial.