Prevalence Of Angle Closure Research Articles

Potential of the Pentacam in Screening for Narrow Angles in Patients with Chronic Angle-Closure Glaucoma

Background: Chronic angle-closure glaucoma (CACG) is a visually destructive disease. Effective management of CACG requires identifying eyes with narrow angle.
 Objective: To compare pentacam with gonioscopy in detecting narrow angles in eyes with CACG.
 Method: We enrolled 101 eyes with glaucoma. Gonioscopy was performed on all eyes. Using Shaffer’s grading, subjects were classified into angle closure and open angle. Anterior chamber volume (ACV) and anterior chamber depth (ACD) were measured with the pentacam. Receiver operating curve was constructed for each parameter and the area under the curve (AUC) was calculated.
 Results: Ten eyes (9.9%) were classified as angle closure on gonioscopy. To detect narrow angles, ACV (AUC 0.956; 95% confidence interval (CI) 0.894–0.987) performed similar to ACD (AUC=0.930, p=0.33). Using a cutoff of 102 mm3 , ACV had 100% sensitivity and 88.5% specificity for detecting narrow angles in CACG patients. With an ACV cutoff of 102 mm3 , the PPV for detecting angle closure was 48.9% (95% CI, 34.8–68.2), while the NPV was 100% (94.1– 100%), using 9.9% prevalence of angle closure from this study.
 Conclusion: ACV and ACD measured by the pentacam have the potential to determine narrow angles in eyes with CACG.
 Keywords: Chronic angle-closure glaucoma, Pentacam HR, Anterior chamber volume, Gonioscopy

Assessment of Circumferential Angle Closure with Swept-Source Optical Coherence Tomography: a Community Based Study

To evaluate the diagnostic performance of swept-source optical coherence tomography (SS-OCT, CASIA SS-1000; Tomey Corporation, Nagoya, Japan) for angle closure detection, in comparison with gonioscopy, in a community setting. Reliability analysis. A total of 2027 phakic subjects aged ≥50 years, with no previous history of glaucoma, laser (including peripheral iridotomy), intraocular surgery, or ocular trauma, were consecutively recruited from a community polyclinic in Singapore. Gonioscopy was performed by a single trained ophthalmologist. SS-OCT angle scans, which obtain radial scans for the entire circumference of the angle, were analyzed by a single examiner, masked to the subject's clinical details. On SS-OCT images, angle closure was defined as contact between the iris and any part of the angle wall anterior to the scleral spur. Different cutoff values of the degree of circumferential angle closure (≥35%, ≥50%, and ≥75%) were taken for analysis to assess SS-OCT performance in detecting angle closure. A total of 1857 subjects (91.6%) were included in the final analysis after excluding poor-quality SS-OCT scans. Almost 90% of the subjects were Chinese, with a mean age of 61.8 ± 6.7 years, and more than half were women (63.5%). The overall AUC of SS-OCT manual grading against gonioscopy was 0.84 (95% confidence interval, 0.81-0.88). The prevalence of angle closure on SS-OCT was 26.1% for the ≥35% definition, with an area under the curve of 0.80 (0.77-0.84), sensitivity of 82.5% (75.3%-88.4%), and specificity of 78.5% (76.5%-80.4%). The first-order agreement coefficient statistics for the 2-quadrant gonioscopic definition of angle-closure with corresponding ≥35%, ≥50%, and ≥75% angle closure definitions for SS-OCT were good at 0.89 (0.83-0.93), 0.88 (0.842-0.93), and 0.88 (0.831-0.99), respectively. In this large community-based study, SS-OCT exhibited moderate performance for angle closure detection compared to gonioscopy as the reference standard.

Comparison of Ciliary Body Anatomy between American Caucasians and Ethnic Chinese Using Ultrasound Biomicroscopy

Purpose: To compare the ciliary body morphology between the Caucasians and Chinese, and to determine the associated anterior segment parameters.Methods: The study groups were comprised of four age- and gender-matched cohorts: American Caucasians, American Chinese, southern and northern mainland Chinese. Ultrasound biomicroscopy (UBM) was performed to assess the following measurements of the ciliary body: trabecular-ciliary process distance (TCPD), trabecular-ciliary process angle (TCA) and ciliary body thickness at 1 mm posterior to the scleral spur (CBT1). A-scan ultrasonography was used to measure lens thickness (LT) and relative lens position (RLP), defined as (ACD + LT/2)/AL.Results: There were 109, 111, 115 and 117 subjects enrolled in the American Caucasian, American Chinese, and southern and northern mainland Chinese groups, respectively. Collectively, the Chinese had smaller TCPD (0.834 ± 0.234 versus 0.940 ± 0.236 mm, p < 0.001) and TCA (75.1 ± 17.9 versus 85.0 ± 21.5, p < 0.001) than Caucasians. No difference was found between the three Chinese subgroups, therefore they were combined as one for the following analyses. After multiple linear regression analysis, adjusting for age, gender, spherical equivalent (SE) and axial length (AL), TCPD and TCA were positively associated with CBT1 and RLP, but negatively correlated with LT in the whole sample. The ethnic Chinese had significantly smaller CBT1 (SRC = −0.177, p < 0.001) and RLP (SRC = −0.254, p < 0.001) than that of Caucasians.Conclusions: Compared with the Caucasians, the Chinese had a thinner ciliary body and a more anteriorly positioned lens, which may contribute to more anteriorly positioned ciliary processes in this population. These findings might help to explain the higher prevalence of angle closure in the Chinese.

Prevalence of angle closure in siblings of patients with primary angle-closure glaucoma.

To determine the frequency of angle closure in siblings of patients with primary angle-closure glaucoma (PACG). In this cross-sectional observational study, siblings of consecutive patients with PACG underwent a comprehensive ophthalmologic examination, including slit-lamp biomicroscopy, measurement of intraocular pressure, stereoscopic optic nerve head examination, and dynamic gonioscopy. Ultrasonic pachymetry was obtained in all subjects; peripapillary retinal nerve fiber layer thickness measurement by optical coherence tomography and standard achromatic perimetry were performed in subjects with angle closure, categorized as primary angle-closure suspect (PACS), primary angle closure (PAC), and PACG, or any suspicion of glaucoma in the presence of open angles. Overall, 95 siblings from 47 families with at least 1 subject affected with PACG participated in the evaluations; 55 (57.9%) individuals were categorized within the spectrum of angle closure, including 34 (35.8%) subjects with PACS, 7 (7.4%)individuals with PAC, and 14 (14.7%) cases of PACG. Nine (9.5%) individuals with open angles demonstrated other abnormal features, these included 3 (3.2%) subjects with suspicious discs, 5 (5.3%) cases of primary open-angle glaucoma, and 1 patient (1.1%) with normal-tension glaucoma. The remaining 31 individuals (32.6%) had no evidence of glaucoma. Our findings indicate familial segregation of angle closure. Siblings of PACG patients are at high risk for the condition, such that two thirds of them demonstrate clinical findings related to glaucoma. These observations suggest a hereditary basis for angle closure; therefore, siblings of patients affected with angle closure should undergo targeted screening for glaucoma.

Angle Closure in the Namil Study in Central South Korea

To assess the prevalence and associated risk factors of angle closure in a defined population as part of the Namil Study. In this cross-sectional epidemiologic study for residents aged 40 years or older in Namil-myon, a rural area in central South Korea, the examination included slitlamp biomicroscopy, applanation tonometry, gonioscopy, autorefraction, fundus photography, corneal thickness measurement, visual field test with frequency-doubling technology, and anterior chamber depth (ACD) and axial length (AL) measurements with partial coherence interferometry. Standard automated field test and optical coherence tomography or scanning laser polarimetry were performed to confirm the glaucomatous visual field/optic disc damage. Angle closure included primary angle-closure suspect (PACS), primary angle closure (PAC), and primary angle-closure glaucoma (PACG). Definitions of PACS, PAC, and PACG were based on the recommendations from the International Society for Geographical &Epidemiological Ophthalmology. Among the 1426 individuals enrolled for the assessment, with exclusion of cataract surgery, the prevalence rates of PACS, PAC, PACG, and overall angle closure in at least 1 eye were 2.0% (95% CI, 1.3%-2.8%), 0.5% (95% CI, 0.1%-0.9%), 0.7% (95% CI, 0.3%-1.1%), and 3.2% (95% CI, 2.3%-4.2%), respectively. Multivariate analysis found that older age (odds ratio [OR], 1.8797; 95% CI, 1.4624-2.4162), shallower ACD (OR, 0.9982; 95% CI, 0.9977-0.9987), and shorter AL (OR 0.9978; 95% CI, 0.9969-0.9988) (P < .001 for each) were significantly associated with angle closure. The overall prevalence of angle closure was 3.2% in the present study. On the basis of these findings, increasing age, shallower ACD, and shorter AL appear to be associated with angle closure. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00727168.

Prevalence and Determinants of Angle Closure in Central Sri Lanka: The Kandy Eye Study

To determine the prevalence and determinants of angle closure in the Kandy District of central Sri Lanka. Population-based, cross-sectional study. Inhabitants aged 40 years or more from villages in the Kandy District were selected by randomized cluster sampling; 1721 eligible participants were identified, and 1375 participated in the study. The examination included slit-lamp examination of the anterior segment, applanation tonometry, static and dynamic gonioscopy, dilated stereoscopic optic disc examination, and ultrasonic ocular biometry. Eyes that were primary angle-closure suspects (PACS) or had primary angle closure (PAC) or primary angle-closure glaucoma (PACG) were identified. Definitions were based on recommendations from the International Society for Geographic and Epidemiological Ophthalmology (ISGEO). Univariate and multivariate logistic regression analyses were performed with angle closure as the outcome variable. Subjects with PACG, PACS, or PAC were pooled into a group considered to have angle closure. The prevalence of PACS, PAC, and PACG in at least 1 eye was 2.35% (95% confidence interval [CI], 0.0-4.7; 32 subjects), 1.86% (95% CI, 0.6-3.1, 25 participants), and 0.57% (95% CI, 0.0-1.2; 7 participants), respectively. The overall prevalence of angle closure was 4.7% (95% CI, 1.1-9.3; 64 participants). The mean axial length in those with angle closure (21.99 mm) was significantly shorter (P<0.001) than in those with open angles (22.47 mm), as was the mean anterior chamber depth (ACD) (2.47 mm compared with 2.81 mm), but the mean lens thickness in those with angle closure (4.51 mm) did not significantly differ (P = 0.44) from those with open angles (4.45 mm). Neither age nor nuclear opalescence was a significant predictor of angle closure in the multivariate model (P = 0.09 and 0.61, respectively); however, female gender was associated with a 9.2 times (P<0.001) increased risk of angle closure, and each millimeter decrease in ACD was associated with a 2.6 times increased risk of angle closure (P<0.001). The overall prevalence of angle closure was 4.7%. Female gender and shallow ACD were significant independent predictors of angle closure in this Sri Lankan population.