Longitudinal Management of Primary Angle Closure Suspect

Abstract

Yuan et al 1 should be commended for their excellent work in designing and implementing a landmark population-based (not hospital-based) study to better elucidate baseline predictive factors that assist clinicians in individualizing management in patients with a diagnosis of primary angle closure suspect (PACS). 1 In a cohort study of data from Chinese patients with untreated control eyes with PACS in the 14-year, single-center Zhongshan Angle Closure Prevention randomized clinical trial, the investigators developed a prediction model for progression from PACS to primary angle closure (PAC) based on intraocular pressure (IOP), central anterior chamber depth (ACD), and limbal ACD. While the risk prediction model with these 3 variables provided moderate performance (area under the curve = 0.69), the inclusion of more sophisticated testing data (ie, anterior segment [AS] optical coherence tomography [OCT] metrics) did not improve the overall predictive performance of the model. Moreover, the ZAP study end point was PAC, not primary angleclosure glaucoma (PACG); no visual field or optic nerve data were presented. At baseline among study participants with untreated PACS, 317 participants (84%) were women, the mean (SD) age was 58.28 (4.71) years, and the mean IOP was approximately 15 mm Hg.In the ZAP trial, 93 of 377 untreated PACS eyes (25%) progressed to having PAC over a 14-year duration, with 88 (95%) of these eyes meeting the end point based on at least 1 clock hour of peripheral anterior synechiae (PAS), 6 eyes (7%) due to IOP greater than 24 mm Hg, and 3 eyes (3%) with an acute angle closure (AAC) episode (eTable 2 in Supplement 1). 1 In a recent publication, the ZAP trial investigators also reported the 14-year clinical outcomes of angle closure prevention with laser peripheral iridotomy (LPI); compared with control eyes, the hazard ratio for progression from PACS to PAC in LPI-treated eyes was 0.31 (95% CI, 0.21-0.46). 2 Although PAC occurrence decreased approximately two-thirds following LPI, the investigators also concluded that the cumulative 14-year risk of progression was relatively low in the community-based PACS population. Of note, eyes treated with LPI had more severe nuclear cataracts, higher IOP, and larger angle width and limbal ACD than control eyes.The prophylactic LPI results from the ZAP trial are comparable to those reported by Baskaran et al 3 from the Singapore Asymptomatic Narrow Angles Laser Iridotomy Study. In the latter randomized clinical trial, the adjusted hazard ratio for progression from PACS to PAC at 5-year follow-up was 0.55 (95% CI, 0.37-0.83) in LPI-treated eyes compared with control eyes; older participants and eyes with higher baseline IOP