Comparing approaches to screening for angle closure in older Chinese adults

Area of Science:

• Ophthalmology
• Glaucoma research
• Diagnostic imaging

Background:

• Primary angle-closure glaucoma (PACG) is a leading cause of preventable blindness.
• Effective screening methods are crucial for early detection and intervention.
• Traditional gonioscopy is the gold standard but requires skilled personnel.

Purpose of the Study:

• To evaluate the diagnostic performance of the scanning peripheral anterior chamber depth analyzer (SPAC) and limbal anterior chamber depth (LACD) for angle closure screening.
• To compare SPAC and LACD against gonioscopy, the established method for diagnosing angle closure.

Main Methods:

• A comparative study involving two clinical populations: the Zhongshan Angle-closure Prevention Trial (370 closed-angle participants) and the Liwan Eye Study (72 open-angle controls).
• Participants underwent assessment using SPAC, LACD, and gonioscopy to determine angle status.
• Receiver operating characteristic (ROC) curve analysis was used to assess diagnostic accuracy.

Main Results:

• Both SPAC and LACD demonstrated high diagnostic accuracy, with Area Under the ROC Curve (AUROC) values of 0.92 for SPAC and 0.94 for LACD.
• LACD exhibited higher sensitivity (94.1%) and specificity (87.5%) compared to SPAC (93.0% sensitivity, 70.8% specificity) at conventional cutoffs.
• Sequential testing with both SPAC and LACD enhanced specificity to 94.4% but reduced sensitivity to 87.0%.

Conclusions:

• Limbal anterior chamber depth (LACD) is a more specific screening tool for angle closure than the scanning peripheral anterior chamber depth analyzer (SPAC) using standard cutoffs.
• While SPAC has lower specificity, its interpretation can be managed by modestly trained personnel.
• Combined sequential testing offers improved specificity, though sensitivity is slightly reduced.