Short-Term Changes in Ocular Biometrics Predict Angle Closure Progression

Results from a recent retrospective cohort study investigating patients with primary angle closure suspect (PACS) to primary angle closure glaucoma (PACG) have indicated that monitoring changes in lens size or position and angle width could potentially boost predictive performance of baseline ocular biometrics and help clinicians prevent long-term angle closure progression.1

Primary open-angle glaucoma (POAG) and PACG are two of the leading causes of irreversible blindness worldwide, collectively affecting over 60 million people annually. PACS alone is predicted to reach 32 million people by 2040. Given that the disease commonly occurs in aging populations, this number is only expected to grow.1,2

“Previous studies, including studies using the ZAP Trial data, identified baseline angle width, anterior chamber depth, axial length, and lens thickness as biometric risk factors for angle closure progression,” wrote Kendra Hong, MD, Roski Eye Institute, Keck School of Medicine of University of Southern California, and colleagues. “While these measurements could form the basis of risk-stratification strategies for identifying PACS eyes that might benefit from earlier intervention, static baseline biometric measurements appear only moderately predictive of clinical outcomes…prompting the need to identify additional factors to improve predictive performance.”1

This study made use of data from the Zhongshan Angle Closure Prevention (ZAP) Trial, a single-center randomized clinical trial conducted in Guangzhou, China, from 2008-2018. Participants between 50 and 70 years were given complete eye examinations, including anterior-segment optical coherence tomography (AS-OCT) imaging, gonioscopy, and ultrasound A-scan biometry. Those with bilateral PACS, which was defined as eyes with ≥2 quadrants of nonvisible pigmented trabecular meshwork on gonioscopy without peripheral anterior synechiae (PAS), intraocular pressure (IOP) >21 mm Hg, or glaucomatous optic neuropathy, were included.1

In the ZAP Trial, 1 eye per patient was randomly chosen to receive laser peripheral iridotomy (LPI); participants were then examined at 2 weeks and 6, 18, 36, 54, and 72 months. Endpoints included incident PACG, which was defined as IOP measurements >24 mm Hg on 2 occasions, development of ≥1 clock hour of PAS in any quadrant, or acute angle closure.1

In the current study, Hong and colleagues reviewed 889 untreated eyes from 889 participants of the ZAP study. Of these, 104 were excluded; a final total of 785 were examined. The mean age (standard deviation SD) was 58.7 (5) years, with no difference noted between the ages of participants with or without progression. The main outcome was progression from PACS to PACG between 36 and 72 months.1

In total, 26 eyes (3.3%) progressed to PACG between 36 and 72 months; 22 developed PAS, 4 developed acute angle closure, and 3 developed elevated IOP. Multivariable Cox models adjusted for age indicated that baseline trabecular-iris space area at 500 µm (TISA500) (hazard ratio [HR] 1.28 per -.01 mm2; 95% CI, 1.09-1.5; P = .006) and ΔLV (HR 1.22 per .1 mm; 95% CI, 1.07-1.41; P = .008) or baseline TISA500 (HR, 1.31 per -.01 mm2; 95% CI, 1.11-1.54, P = .003) and ΔTISA750 (HR 1.06 per -.01 mm2; 95% CI, 1.02-1.1; P = .009) were more predictive than baseline TISA500 alone (HR, 1.27 per -.01 mm2; 95% CI, 1.09-1.49; P = .007).1

This data indicated to Hong and colleagues that 18-month changes in LV and TISA750 are predictive of progression from PACS to PACG between 36 and 72 months. The team suggests that serial measurements can quantify anatomical changes more precisely over time, thereby helping clinicians identify high-risk eyes that could benefit from earlier treatment.1

“Recent technological developments have also made AS-OCT imaging and measurements more accessible for routine clinical use,” Hong and colleagues wrote. “However, further work is needed to evaluate anatomical changes across larger, more diverse populations with the goal of advancing the utility of AS-OCT imaging and improving the accuracy of risk-stratification in the care of patients with [PACG].”1

References

1. Hong KL, Xu BY, Wang W, et al. Short-Term Ocular Biometric Changes as Predictors of Long-Term Angle Closure Progression. JAMA Ophthalmol. Published online May 29, 2025. doi:10.1001/jamaophthalmol.2025.1007

2. Tham Y-C, Li X, Wong TY, Quigley HA, Aung T, Cheng C-Y. Global prevalence of glaucoma and projections of glaucoma burden through 2040. Ophthalmology. 2014;121(11):2081-2090. doi:10.1016/j.ophtha.2014.05.013