Primary Angle Closure Disease Research Articles

Comparison of intraocular pressure and anterior segment parameters in subjects with asymmetrical primary angle closure disease.

To compare intraocular pressure (IOP) and anterior segment parameters between eyes with unilateral primary angle closure glaucoma (PACG) and their fellow eyes with primary angle closure (PAC) or primary angle closure suspect (PACS). Subjects underwent anterior segment imaging using 360-degree swept-source optical coherence tomography (SS-OCT, CASIA Tomey, Nagoya, Japan) and ocular investigations including gonioscopy and IOP measurement. Each SS-OCT scan (divided into 8 frames, 22.5 degrees apart) was analysed and an average was obtained for the following anterior segment parameters: iridotrabecular contact (ITC), angle opening distance (AOD750), iris thickness and curvature, anterior chamber width, depth and area (ACW, ACD and ACA) and lens vault (LV). Among 132 unilateral PACG subjects (mean age: 62.91 ± 7.2 years; 59.1% male), eyes with PACG had significantly higher presenting IOP (24.81 ± 0.94 vs. 18.43 ± 0.57 mmHg, p < 0.001), smaller gonioscopic Shaffer grade (2.07 ± 0.07 vs. 2.31 ± 0.07, p < 0.001) and a greater extent of peripheral anterior synechiae (PAS, 1.21 ± 0.21 vs. 0.54 ± 0.16 clock hours, p = 0.001). PACG eyes also exhibited increased ITC, ITC area, greater LV and smaller AOD750, ACD and ACA (all p < 0.05). Using the forward stepwise regression model, an increase in 1 mmHg in presenting IOP before laser peripheral iridotomy (LPI)increases the odds of having PACG by 9% (95% confidence interval 5%-14%). PACG eyes have higher presenting IOP, smaller anterior segment parameters, greater extent of PAS, and larger LV compared to their fellow eyes with angle closure. Narrower anterior chamber dimensions and higher presenting IOP before LPI may increase risk of chronic elevated IOP and glaucomatous optic neuropathy after LPI.

Comparison of Different Intraocular Lens Power Calculation Formulas in Eyes with Primary Angle Closure.

To compare the accuracy of six intraocular lens power calculation formulas, Barrett Universal Ⅱ (BU Ⅱ), Haigis, Hoffer QST, HolladayⅠ, Kane and SRK/T, in eyes with primary angle closure disease (PACD). Xiamen University Affiliated Xiamen Eye center, Xiamen, Fujian, China. Prospective case series. Patients diagnosed with PACD and cataract and met the indication for cataract surgery were enrolled in the study. Six intraocular lens power calculation formulas were used to calculate refractive diopter. Percentage of eyes with prediction error (PE) within ±0.50D, and the median absolute prediction error (MedAE) were compared to determine the accuracy of different formulas in PACD patients. Subgroup analysis was performed according to axial length (AL). The accuracy of Barrett Universal Ⅱ was compared between PACD patients and age-related cataract patients. 105 patients (105 eyes) with PACD and 35 patients (35 eyes) with age-related cataract were enrolled in the study. Haigis, Kane and Barrett Universal Ⅱ formula achieved a comparable outcome and outperformed over the other three formulas in PACD patients. Subgroup analysis showed that the group with long AL has lower values of MedAE. PE was significantly positively correlated with AL and negatively correlated with relative lens position (RLP) when calculated use Barrett Universal Ⅱ and Kane. Haigis, Kane and Barrett Universal Ⅱ formula achieved a comparable outcome and outperformed over the other three formulas in PACD patients.

Location-Based Success Rates of Nd:YAG Laser Peripheral Iridotomy in Patients with Primary Angle Closure Disease and Primary Angle Closure Glaucoma at Khmer Soviet Friendship Hospital, Cambodia

Location-Based Success Rates of Nd:YAG Laser Peripheral Iridotomy in Patients with Primary Angle Closure Disease and Primary Angle Closure Glaucoma at Khmer Soviet Friendship Hospital, Cambodia

Zonular instability-associated morphologic features in eyes with primary angle closure disease using the swept-source anterior segment – optical coherence tomography system

BackgroundThis study aims to investigate the morphologic features of the crystalline lens in Primary Angle Closure Disease (PACD) patients with zonular instability during cataract surgery using the swept-source CASIA 2 Anterior Segment-Optical Coherence Tomography (AS-OCT) system.MethodsA total of 398 eyes (125 PACD eyes with zonular instability, 133 PACD eyes with zonular stability, and 140 cataract patient controls) of 398 patients who underwent cataract surgery combined or not glaucoma surgery between January 2021 and January 2023 were enrolled. The crystalline lens parameters were measured by CASIA2 AS-OCT. Then, logistic regression was performed to evaluate the risk factors associated with zonular instability.ResultsThe results revealed that PACD eyes had a more anterior lens equator position, a steeper anterior curvature of lens, shorter Axial Length (AL), shallower Anterior Chamber Distance (ACD), higher Lens Vault (LV) and thicker Lens Thickness (LT), when compared to eyes in the cataract control group. Furthermore, PACD eyes in the zonular instability group had steeper front R, front Rs and Front Rf, flatter back Rf, thicker lens anterior part thickness, higher lens anterior-to-posterior part thickness ratios, shallower ACD, and greater LV, when compared to PACD eyes with zonular stability. The logistic regression analysis, which was adjusted for age and gender, revealed that zonular instability was positively correlated with anterior part thickness, lens anterior-to-posterior part thickness ratio, and LV, but was negatively correlated with lens anterior radius and ACD.ConclusionSteeper anterior curvature, increased lens anterior part thickness, higher anterior-to-posterior part thickness ratio, shallower ACD, and greater LV are the anatomic features of PACD eyes associated with zonular instability.

Zonulopathy and its Relation to Primary Angle Closure Disease: A Narrative Review.

This paper aims to discuss the anatomical features of zonule fibers that centers the lens in the eye and summaries the relationship between zonulopathy and PACD.

Performance of anterior segment OCT-based algorithms in the opportunistic screening for primary angle-closure disease

PurposeThis study aimed to investigate the performance of deep learning algorithms in the opportunistic screening for primary angle-closure disease (PACD) using combined anterior segment parameters. MethodsThis was an observational, cross-sectional hospital-based study. Patients with PACD and healthy controls who underwent comprehensive eye examinations, including gonioscopy and anterior segment optical coherence tomography (ASOCT) examinations under both light and dark conditions, were consecutively enrolled from the Department of Ophthalmology at the Beijing Tongren Hospital between November 2020 and June 2022. The anterior chamber, anterior chamber angle, iris, and lens parameters were assessed using ASOCT. To build the prediction models, backward logistic regression was utilized to select the variables to discriminate patients with PACD from normal participants, and the area under the receiver operating characteristic curve was used to evaluate the efficacy of the opportunistic screening. ResultsThe data from 199 patients (199 eyes) were included in the final analysis and divided into two groups: PACD (109 eyes) and controls (90 eyes). Angle opening distance at 500 μm, anterior chamber area, and iris curvature measured in the light condition were included in the final prediction models. The area under the receiver operating characteristic curve was 0.968, with a sensitivity of 91.74 % and a specificity of 91.11 %. ConclusionASOCT-based algorithms showed excellent diagnostic performance in the opportunistic screening for PACD. These results provide a promising basis for future research on the development of an angle-closure probability scoring system for PACD screening.

Genetic Associations of Primary Angle-Closure Disease

Effects of genetic variants on primary angle-closure disease remained uncertain. To systematically review the associations of common single-nucleotide variants (SNVs) and rare coding variants with primary angle-closure disease, its subtypes (including primary angle-closure glaucoma, primary angle-closure suspect, and primary angle-closure) and progression. Eligible studies from PubMed, Embase, and Web of Science were retrieved up to April 3, 2023. SNV information was extracted from eligible reports and 2 genome-wide association studies summary statistics, UK BioBank and FinnGen. Studies providing analyzable genotype or allele data in a case-control design for primary angle-closure disease association and longitudinal case-only design for primary angle-closure disease progression. PRISMA guidelines were used for literature screening and the Newcastle Ottawa Scale for data quality assessment. Pooled effect size with 95% CIs of SNV associations were calculated using fixed- or random-effect models according to I2 statistics. SNVs reported in 2 or more studies were meta-analyzed to generate pooled odds ratios and P values. Common and rare coding variants from single reports were summarized. Sixty-nine citations were eligible for meta-analysis on overall primary angle-closure disease, involving 206 SNVs in 64 genes or loci. Seventeen SNVs in 15 genes or loci showed associations with primary angle-closure disease, and 15 SNVs in 13 genes or loci showed associations with primary angle-closure glaucoma. Two SNVs, ABCA1 rs2422493 and ZNRF3 rs3178915, were associated only with primary angle-closure disease. Two SNVs, PCMTD1-ST18 rs1015213 and COL11A1 rs3753841, were associated with primary angle-closure suspect, and 1 SNV, MMP9 rs3918249, was associated with primary angle-closure. This systematic review and meta-analysis newly confirmed 7 genes or loci associated with primary angle-closure glaucoma: ATOH7, CALCRL, FBN1, IL6, LOXL1, MMP19, and VAV3. Common and rare coding variants in 16 genes or loci that have been associated with primary angle-closure disease were cataloged. Stratification analysis revealed different primary angle-closure disease-associated genes in different ethnic populations. Only 1 study regarding the genetic association of primary angle-closure glaucoma progression was identified. This study revealed the genetic complexity of primary angle-closure disease, involving common SNVs and rare coding variants in more than 30 genes or loci, with ethnic and phenotypic diversities. Further replication, genotype-phenotype correlation, and pathway analyses are warranted.

Long-Term Efficacy of Selective Laser Trabeculoplasty in Primary Angle-Closure Disease After Laser Peripheral Iridotomy

ABSTRACT Purpose To evaluate the long-term efficacy of selective laser trabeculoplasty (SLT) in eyes with primary angle-closure (PAC) and primary angle-closure glaucoma (PACG) following a laser peripheral iridotomy (LPI). Method In this prospective cross-sectional study, 45 eyes of 34 patients with PAC/PACG diagnosis, uncontrolled intraocular pressure (IOP), and visible pigmented trabecular-meshwork (TM) at least 180° on gonioscopy following a LPI were recruited. Following a detailed baseline ophthalmic evaluation, all eligible eyes underwent SLT, and the patients were examined on day1, at 1 week, 1-, 3-, and 6-months, and 1-, 2-, 3-, 4-, and 5-year subsequently. The main outcomes measured were IOP, number of IOP-lowering agents, and complications. Results The mean age of the cohort was 57.80 ± 6.44 years, the male–female ratio was 8:26, and 17 eyes were PACG, and 28 were PAC. The baseline IOP was 23.81 ± 1.78 mm Hg, and was significantly declined at all follow-ups (p < .0001). The cumulative probability of overall success was 91% and 84% at 2-, and 5-year, respectively. At 5-year SLT provided drug-freedom in 80% of PAC and 23% of PACG eyes. Six eyes had IOP spike at 1-week and two patients underwent repeat SLT after 1-year. No other complications, such as pain/discomfort, inflammation, an increase in peripheral anterior synechiae and cystoid-macular-edema, were noted. Conclusions SLT appears a safe and cost-effective procedure in PAC/mild- moderate PACG eyes with uncontrolled IOP after laser iridotomy. The long-term effectiveness of SLT as adjuvant treatment was good, but need large sized randomized studies for more validation.

Direct observation and measurement of circumlental space and its relation to anterior chamber angle characteristics in iridotomized phakic eyes with primary angle closure disease

Primary angle closure disease (PACD) is a major cause of blindness worldwide. It has a high prevalence in East Asia, especially in China, which leads to a higher incidence of blindness than open-angle glaucoma. The aim of this study was to directly observe the circumlental space (CLS) in laser peripheral iridotomized eyes with PACD and to determine whether this structure plays a role in the pathogenesis of PACD. Fifty eyes of 50 patients with PACD, who had received laser peripheral iridotomy performed with neodymium:yttrium–aluminum-garnet were recruited from glaucoma clinics from March 2021 to May 2022, including 17 primary angle closure suspect (PACS), 16 primary angle closure (PAC) and 17 primary angle closure glaucoma (PACG). They were classified into two groups based on whether the ciliary process and the crystalline lens equator were in contact using slit-lamp photograph: the attached group and the unattached group. The demographic, clinical characteristics and anterior segment parameters measured from ultrasound biomicroscopy were compared between the attached group and the unattached group. Thirty-three eyes were assigned to the attached group and 17 eyes belonged to the unattached group. In the unattached group, the mean CLS was 0.10 ± 0.07 mm. No significant differences were identified between the different diagnosis groups in age, sex, best-corrected visual acuity, intraocular pressure, white-to-white, axial length, central corneal thickness, anterior chamber depth, flat keratometry, steep keratometry or iridotomy diameter (p > 0.05). The unattached group had shorter trabecular-ciliary process distance (p = 0.021) and larger ciliary process area (p = 0.001) compared with the attached group. Small CLS and its potential effect (partial ciliary block) might be considered as one of the mechanisms of PACD.

Phacoemulsification combined with goniosynechialysis versus phacoemulsification alone for patients with primary angle‑closure disease: A meta-analysis.

This meta-analysis aims to systematically compare the efficacy between phacoemulsification (PE) combined with goniosynechialysis (GSL) and PE alone for primary angle-closure disease (PACD) patients. All the data were searched from the PubMed, EMBASE and the Cochrane Library. The Cochrane Handbook was used to evaluate the quality of the included studies. Additionally, this meta-analysis was performed by using the Revman 5.4 software. Nine randomized controlled trials (RCTs) were included in this study. Compared with PE alone group, PE+GSL could result significant reduction in the IOP (MD, 1.81; p = 0.002). In the instrumental subgroup, also more reduction of IOP was shown in the PE+GSL group (MD, 2.11; p = 0.02). In the viscogonioplasty (VGP) subgroup, there was not no statistical difference between PE alone group and PE+GSL group (MD, 1.53; p = 0.11). Also, more reduction of peripheral anterior synechiae (PAS) was shown in the PE+GSL group (MD,59.15; p<0.00001). For the change in angle open distance (AOD)500, AOD 750, trabecular-iris space (TISA)500, number of glaucoma medications and best corrected visual acuity (BCVA), there was no difference between two groups (p = 0.25, 0.35, 0.17, 0.56, 0.08). For TISA 750, more improvement was shown in the PE+GSL group (p<0.00001). Instrumental separation had better effect on lowering IOP when it combined with PE. Both instrumental separation and VGP could reduce postoperative PAS. The operation of GSL has no obvious effect on postoperative vision.

Quantitative analysis of dynamic iris changes in primary angle-closure disease with long axial lengths: the Handan Eye Study.

To investigate dynamic iris changes in patients with primary angle-closure disease (PACD) with long axial length (AL) compared to those with short and medium AL. This observational cross-sectional study enrolled participants aged 35 years or older from the Handan Eye Study follow-up examination who were diagnosed with PACD and underwent Visante anterior segment optical coherence tomography (ASOCT) imaging under light and dark conditions. The right eye of each participant was included in the analysis. AL was categorized as short (<22.0 mm), medium (≥22.0 to ≤23.5 mm), or long (>23.5 mm). Anterior segment parameters, including iris dynamic changes, were compared among the three groups with different ALs. Data from 448 patients with PACD were analyzed. We found that 10.9% of included eyes had a long AL with a flatter cornea; larger central anterior chamber depth, angle opening distance, anterior chamber width, anterior chamber area, and volume; and smaller lens thickness and lens vault (LV) (P < 0.05) than those with short AL. No significant difference existed between the three groups in iris thickness, iris cross-sectional area (IA), iris curvature, or pupil diameter (PD) change between light and dark (P > 0.05). The significant associated factors for IA changes were area recess area (ARA) in the dark, LV in the dark, and PD change from light to dark (P < 0.05). Dynamic and static iris parameters were consistent across patients with PACD with short, medium, or long AL and may contribute to the pathogenesis of angle closure in atypical PACD.

Agreement and Reproducibility of Anterior Chamber Angle Measurements between CASIA2 Built-In Software and Human Graders.

This study evaluated the agreement and reproducibility of ACA measurements obtained using the built-in software of the CASIA2 (Version 3G.1) and the measurements derived from expert clinicians. Healthy volunteers underwent ophthalmological evaluation and AS-OCT examination. ACA measurements derived from automated and manual SS location were obtained using the CASIA2 automated software and clinician identification, respectively. The intraobserver, interobserver reproducibility, CASIA2-human grader reproducibility and CASIA2 repeatability were assessed using intraclass correlation coefficients (ICCs). The study examined 58 eyes of 30 participants. The CASIA2 software showed excellent repeatability for all ACA parameters (ICC > 0.84). Intraobserver, interobserver, and CASIA2-human grader reproducibility were also excellent (ICC > 0.87). Interobserver agreement was high, except for nasal TISA500, differing between observers 1 and 2 (p < 0.05). The agreement between CASIA2 measurements and human graders was high, except for nasal TISA500, where observer 1 values were smaller (p < 0.05). The CASIA2 built-in software reliably measures ACA parameters in healthy individuals, demonstrating high consistency. Although a small difference was observed in nasal TISA500 measurements, interobserver and CASIA2-human grader reproducibility remained excellent. Automated SS detection has the potential to facilitate evaluation and monitoring of primary angle closure disease.

Prevalence of glaucoma types, clinical profile and disease severity at presentation: Tertiary Institute based cross-sectional study from South India.

To describe the clinical profile and relative prevalence of subtypes of glaucoma presenting to a tertiary care center in India. This cross-sectional hospital-based study included 6,120 new patients (>16 years) presenting between January 2016 and December 2017. The data were collected using an electronic medical record system. A total of 11,016 eyes of 6,120 new patients were diagnosed with glaucoma. Sixty-one percent were male and 79% had a bilateral affliction. Primary glaucoma was present in 4,352 (71.1%) and secondary glaucoma in 1,063 (17.4%) subjects. Glaucoma was primary open-angle (POAG) in 4,015 (36.4%) eyes and primary angle closure disease (PACD) in 3,806 (34.5%) eyes. Commonest among secondary glaucoma was post-cataract surgery glaucoma (3.1%), neovascular glaucoma (2.4%), pseudoexfoliation glaucoma (PXG) (2.1%), and steroid-induced glaucoma (SIG) (1.4%). Patients with primary glaucoma were older than secondary (56.6 ± 0.2 vs 54.1 ± 0.4; P < 0.0001). Mean IOP was higher in secondary glaucoma compared to primary (26.9 ± 0.3 vs 18.9 ± 0.1; P < 0.0001). Secondary glaucoma had greater mean CDR compared to primary glaucoma (0.77 ± 0.007 vs 0.70 ± 0.003; P < 0.0001). The prevalence of blindness (visual acuity <20/200) was 16.2% of eyes. Mean deviation (MD) 20db or worse was noted in 39.5% of eyes at presentation including 47.8% of PACG, 37.3% of POAG, 51% of JOAG, 58% of PXG, and 45% of SIG, suggesting disease severity. At the presentation to a tertiary care center, 40% of all eyes with glaucoma had advanced disease with MD worse than - 20D. PACG and JOAG had the worse disease among primary; among secondary, PXG and SIG had the worse disease at presentation.

Progressive Changes in the Anterior Segment and Their Impact on the Anterior Chamber Angle in Primary Angle Closure Disease

To investigate longitudinal changes in the anterior segment (AS) using serial optical coherence tomography (OCT) images and determine impact of these changes on the anterior chamber angle (ACA) in eyes with primary angle closure disease (PACD) treated with laser peripheral iridotomy (LPI). Retrospective clinical cohort study. This study included 103 patients with PACD who underwent LPI and were followed-up by a mean 6.7 ± 1.7 AS-OCT examinations for a mean 6.5 ± 2.9 years. Temporal changes in AS-OCT parameters, including anterior chamber depth (ACD), angle opening distance (AOD750), angle recess area (ARA750), iris thickness (IT750), lens vault (LV), and pupil diameter (PD), were analyzed by multivariate linear mixed effects models (LMEMs). Multivariate LMEMs showed that decrease in AOD750 was not significant (-1.59 μm/yr, p = 0.222), however, ARA750 decreased over time (-2.3 × 103 μm2/yr, p = 0.033) and SSA showed marginal significance (-0.20°/yr, p = 0.098), and LV increased significantly (11.6 μm/year, p < 0.001) after LPI. Mean LV change was negatively associated with AOD750, ARA750 and SSA, while PD was negatively associated with ARA750 (p < 0.001 each). PD decreased with aging (-13.7 μm/year, p = 0.036) accompanied by thinning of IT750 (-1.7 μm/year, p = 0.063). LV tends to increase with aging which contributes to the shallowing of the anterior chamber and narrowing of ACA in PACD eyes treated with LPI. In the meantime, pupillary constriction and subsequent peripheral iris thinning associated with aging could possibly offset the effect of ACA narrowing.

Twenty-Four-Hour Intraocular Pressure in Chronic Primary Angle-Closure Disease.

Primary angle closure and primary angle closure glaucoma may exhibit normal intraocular pressure. Twenty-four-hour intraocular pressure fluctuation is highest in primary angle closure glaucoma. The degree of peripheral anterior synechiae was associated with a 24-hour intraocular pressure pattern in primary angle-closure disease without laser iridotomy. The purpose of this study was to study 24-hour intraocular pressure (IOP) patterns in eyes with chronic primary angle-closure disease and evaluate associations between peripheral anterior synechiae (PAS) and 24-hour IOP pattern. In this prospective cohort study, 59 eyes of 35 Asian patients with chronic primary angle-closure disease underwent complete ocular examinations at Ramathibodi Hospital, Mahidol University. Twenty-four-hour IOP records were obtained using Goldmann applanation tonometry at 2-hour intervals. Peak, mean, and trough 24-hour IOP values and 24-hour IOP fluctuation (difference between peak and trough values) were compared among groups. None of the participants received any treatment before complete data collection. Even univariable analysis demonstrated a significant difference in peak, mean, and trough IOP and 24-hour IOP fluctuation between the 3 groups; the magnitude of trough IOP was not higher than 21mmHg in all groups. In multivariable analysis, PAC and PACG eyes showed significantly higher peak IOP ( P =0.020 and 0.006, respectively) and 24-hour IOP fluctuation ( P =0.048 and 0.001, respectively) compared with PACS eyes. In comparison between combined PACS and PAC eyes versus PACG eyes, PACG eyes revealed significantly higher 24-hour IOP fluctuation. The degree of PAS was associated with peak and mean IOP values and with 24-hour IOP fluctuation in PAC and PACG eyes. Twenty-four-hour IOP fluctuation was highest in PACG eyes. Although PAC and PACG eyes showed higher peak IOP and 24-hour IOP fluctuation values, compared with PACS eyes, trough IOP in PAC and PACG eyes were mostly below 21mmHg. In addition, the degree of PAS was associated with a 24-hour IOP pattern in either PAC or PACG eyes.

Deep Learning Classification of Angle Closure based on Anterior Segment OCT

To assess the performance and generalizability of a convolutional neural network (CNN) model for objective and high-throughput identification of primary angle-closure disease (PACD) as well as PACD stage differentiation on anterior segment swept-source OCT (AS-OCT). Cross-sectional. Patients from 3 different eye centers across China and Singapore were recruited for this study. Eight hundred forty-one eyes from the 2 Chinese centers were divided into 170 control eyes, 488 PACS, and 183 PAC+ PACG eyes. An additional 300 eyes were recruited from Singapore National Eye Center as a testing data set, divided into 100 control eyes, 100 PACS, and 100 PAC+ PACG eyes. Each participant underwent standardized ophthalmic examination and was classified by the presiding physician as either control, primary angle-closure suspect (PACS), primary angle closure (PAC), or primary angle-closure glaucoma (PACG). Deep Learning model was used to train 3 different CNN classifiers: classifier 1 aimed to separate control versus PACS versus PAC+ PACG; classifier 2 aimed to separate control versus PACD; and classifier 3 aimed to separate PACS versus PAC+ PACG. All classifiers were evaluated on independent validation sets from the same region, China and further tested using data from a different country, Singapore. Area under receiver operator characteristic curve (AUC), precision, and recall. Classifier 1 achieved an AUC of 0.96 on validation set from the same region, but dropped to an AUC of 0.84 on test set from a different country. Classifier 2 achieved the most generalizable performance with an AUCof 0.96 on validation set and AUC of 0.95 on test set. Classifier 3 showed the poorest performance, with an AUC of 0.83 and 0.64 on test and validation data sets, respectively. Convolutional neural network classifiers can effectively distinguish PACD from controls on AS-OCT with good generalizability across different patient cohorts. However, their performance is moderate when trying to distinguish PACS versus PAC+ PACG. The authors have no proprietary or commercial interest in any materials discussed in this article.

Prediction of postoperative effective lens position using iris root depth in primary angle-closure diseases.

To evaluate the role of a new parameter, iris root depth (IRD), in intraocular lens power calculation using ultrasound biomicroscopy (UBM) in primary angle-closure diseases (PACDs), and to compare the accuracy of 6 formulas in PACDs: Barrett Universal II (BUII), Haigis, Hill-Radial Basis Function (RBF) v. 3.0, Hoffer Q, Kane and Sanders Retzlaff Kraff/Theoretical (SRK)/T. Zhongshan Ophthalmic Center, Guangzhou, China. Retrospective consecutive case series. Patients diagnosed with PACDs who had undergone cataract surgery were reviewed to first evaluate the performance of 6 formulas. Then preoperative UBM examinations of 58 eyes were used to measure IRD and predict effective lens position (ELP) to generate the Haigis IRD formula. The accuracy of Haigis IRD was compared with BUII, Haigis and Kane formulas. The SD of predicted error was the main indicator evaluating formula performance, according to heteroscedastic analysis. 103 eyes (103 patients) were included. The SDs of Kane (0.59, P = .01), RBF 3.0 (0.61, P = .02) and SRK/T formula (0.62, P = .04) were significantly lower than Hoffer Q. Modified with IRD, Haigis IRD generated the lowest SD (0.41), which was significantly lower than Haigis formula (0.54, P = .03) and was equal to Kane formula (0.45, P = .37). Kane, RBF 3.0 and SRK/T were more accurate in PACD eyes. Optimized with IRD, Haigis IRD formula achieved the lowest SD and had comparable accuracy with Kane formula. IRD could be a promising parameter to improve accuracy of IOL power calculation for PACDs.

Evaluation of Schlemm’s canal with swept-source optical coherence tomography in primary angle-closure disease

PurposeTo perform an in vivo evaluation of the changes in Schlemm’s canal (SC) among patients with primary angle-closure disease (PACD) using swept-source optical coherence tomography (SS-OCT).MethodsPatients diagnosed with PACD who had not undergone surgery were recruited. The SS-OCT quadrants scanned herein included the nasal and temporal sections at 3 and 9 o’clock, respectively. The diameter and cross-sectional area of the SC were measured. A linear mixed-effects model was performed to analyze the effects of parameters on the SC changes. The hypothesis of interest was related to the angle status (iridotrabecular contact, ITC/open angle, OPN), which was further explored with pairwise comparisons of the estimated marginal means (EMMs) of the SC diameter and SC area. In the ITC regions, the relationship between the trabecular-iris contact length (TICL) percentage and SC parameters was also studied by a mixed model.ResultsA total of 49 eyes of 35 patients were included for measurements and analysis. The percentage of observable SCs in the ITC regions was only 58.5% (24/41), whereas it was 86.0% (49/57) in the OPN regions (χ2 = 9.44, p = 0.002). ITC was significantly associated with a decreasing SC size. The EMMs for the diameter and cross-sectional area of SC at the ITC and OPN regions were 203.34 μm versus 261.41 μm (p = 0.006) and 3174.43 μm2 versus 5347.63 μm2 (p = 0.022), respectively. Sex, age, spherical equivalent refraction, intraocular pressure, axial length, extent of angle closure, history of acute attack and treatment with LPI were not significantly associated with SC parameters. In the ITC regions, a larger TICL percentage was significantly associated with a decrease in SC diameter and area (p = 0.003 and 0.019, respectively).ConclusionsThe morphologies of SC could be affected by the angle status (ITC/OPN) in patients with PACD, and ITC was significantly associated with a decreasing SC size. These changes in SC as described by OCT scans might help to elucidate the progression mechanisms of PACD.

Zonulopathy Identified During Cataract Extraction in Patients With Primary Angle Closure Disease.

The proportion, clinical characteristics, and risk factors of zonulopathy in Primary Angle Closure Disease (PACD) were analyzed. Zonulopathy is an under-recognized common finding in PACD, especially in acute angle closure patients. To examine the proportion and risk factors associated with intraoperative zonulopathy in primary angle closure disease (PACD). This is a retrospective analysis of 88 consecutive PACD patients who underwent bilateral cataract extraction at Beijing Tongren Hospital from August 1, 2020 to August 1, 2022. Zonulopathy was diagnosed based on intraoperative findings including the presence of lens equator, radial folds of the anterior capsule while making capsulorhexis, and other signs of unstable capsular bag. The subjects were grouped based on their PACD subtype diagnoses: acute angle closure (AAC), primary angle closure glaucoma (PACG), primary angle closure (PAC), or primary angle closure suspect (PACS). Multivariate logistic regression was performed to identify risk factors associated with zonulopathy. The proportion and the risk factors of zonulopathy were estimated in PACD patients and in PACD subtypes. Of 88 PACD patients (67.3±6.9y old, 19 male, 69 female), the overall proportion of zonulopathy was 45.5% of patients (40/88) and 30.1% of eyes (53/176). Among the PACD subtypes, the proportion of zonulopathy was highest (69.0%) in AAC, followed by 39.1% in PACG, and 15.3% in PAC and PACS combined. AAC was an independent risk factor associated with zonulopathy (P= 0.015, AAC vs PACG, PAC and PACS combined, OR 0.340, CI 0.142-0.814). Shallower anterior chamber depth (P=0.031) and greater lens thickness (P= 0.036), but not laser iridotomy, were associated with increased proportion of zonulopathy. Zonulopathy is common in PACD, especially in AAC patients. Shallow ACD and thick LT were associated with increased proportion of zonulopathy.

Publication trends of primary angle-closure disease during 1991-2022: a bibliometric analysis.

To perform a bibliometric analysis in the field of primary angle-closure disease (PACD) research to characterize current global trends and compare contributions from different countries, institutions, journals, and authors. All PACD-related publications from 1991 to 2022 from the Web of Science Core Collection database were extracted. Microsoft Excel and VOSviewer were used to collect publication data, analyze publication trends, and visualize relevant results. A total of 1721 publications with 34 591 citations were identified. China produced the most publications (554) while ranking third in citations (8220 times). The United States contributed the most citations (12 315 times) with publications (362) ranking second. The Investigative Ophthalmology Visual Science was the most productive journal concerning PACD, and Aung Tin was the author with the highest number of publications in the field. Keywords were classified into three clusters, epidemiology and pathogenesis research, optical coherence tomography (OCT) and other imaging examinations, and glaucoma surgery treatment. Genome-wide association, susceptibility loci, OCT, and combined phacoemulsification have become new hot research topics in recent years since 2015. China, the United States, and Singapore make the most outstanding contributions in the field of PACD research. OCT, combined phacoemulsification, and gene mutation-related study, are considered the potential focus for future research.