Comparing approaches to screening for angle closure in older Chinese adults

Abstract

Aims Primary angle-closure glaucoma is expected to account for nearly 50% of bilateral glaucoma blindness by 2020. This study was conducted to assess the performance of the scanning peripheral anterior chamber depth analyzer (SPAC) and limbal anterior chamber depth (LACD) as screening methods for angle closure. Methods This study assessed two clinical populations to compare SPAC, LACD, and gonioscopy: the Zhongshan Angle-closure Prevention Trial, from which 370 patients were eligible as closed-angle participants and the Liwan Eye Study, from which 72 patients were selected as open-angle controls. Eligible participants were assessed by SPAC, LACD, and gonioscopy. Results Angle status was defined by gonioscopy. Area under the receiver operating characteristic curve (AUROC) for SPAC was 0.92 (0.89-0.95) whereas AUROC for LACD was 0.94 (0.92-0.97). Using conventional cutoff points, sensitivity/specificity was 93.0%/70.8% for SPAC and 94.1%/87.5% for LACD. Sequential testing using both SPAC and LACD increased the specificity to 94.4% and decreased the sensitivity to 87.0%. Conclusion SPAC has significantly lower specificity than LACD measurement using conventional cutoffs but interpretation of the findings can be performed by modestly trained personnel.

Noncontact Screening Methods for the Detection of Narrow Anterior Chamber Angles

“…Several studies have reported on the performance of the van Herick test for detection of gonioscopically occludable angles. 4,6,17,23,28,29 Some have described its superior performance over other noninvasive screening tests, such as ultrasound pachymetry, optical pachymetry, or the scanning peripheral anterior chamber depth analyzer. 23,29 Conversely, others questioned the technique's utility in screening for angle closure.…”

Screening for Narrow Angles in the Japanese Population Using Scanning Peripheral Anterior Chamber Depth Analyzer

“…The van Herick technique was employed for primary screening in previous epidemiologic studies of ACG eyes [21]. It has been reported that the results of peripheral ACD measurement by SPAC were well correlated with those by the van Herick technique as well as Shaffer's grading system and the ultrasound biomicroscope [22]. As the sequential testing using both SPAC and van Herick demonstrates high specificity and sensitivity [23], we considered that the SPAC examination in conjunction with the van Herick method is considered as a choice of the first-line screening tests for angle closure following precise examination by OCT, UBM, or gonioscopy.…”

“…When using gonioscopy as the gold standard [8,10], the performance of SPAC combined grade (P or S and/or ≤ grade 5) gave a sensitivity and specificity of 93.0% and 70.8%, respectively [19]. With sequential testing using both SPAC and van Herick, the specificity and sensitivity improves to 94.4% and 87.0%, respectively [21,22]. Therefore, the SPAC examination in conjunction with the van Herick method is considered as a choice of the first-line screening tests for angle closure following precise examination by OCT, UBM, or gonioscopy ( Fig.…”

“…Their protocol consisted of 2 phases: primary screening using SPAC measurements of ACD by nonphysicians and definitive examination by glaucoma specialists (Fig. 4), and was revealed useful for detecting eyes at risk of angle closure glaucoma [22].…”

Guangzhou Diabetic Eye Study: rationale, design, methodology and baseline data

“…The angles were evaluated from the limbal nose and temporal quadrant with a narrow slit beam of about 45 degrees, then all the participants’ eyes were dilated. 14 In the event of any uncertainty during angle width assessment, an ophthalmologist with higher seniority performed a second examination. After pupil dilation, ophthalmoscopy was used with a slit lamp bio-microscope for posterior segment assessment and any detected abnormalities of the vitreous body and retina were recorded.…”