Ocular Biometric Risk Factors for Progression of Primary Angle Closure Disease: The Zhongshan Angle Closure Prevention Trial

Patterns and Disparities in Recorded Gonioscopy During Initial Glaucoma Evaluations in the United States

PURPOSE

To assess patterns in gonioscopy during initial glaucoma evaluations in the United States.

DESIGN

Retrospective, case-control study.

METHODS

Patients undergoing initial glaucoma evaluation between 2009-2020 were identified in the Optum Clinformatics DataMart. Initial evaluation was defined as follows: (1) glaucoma suspect, anatomical narrow angle (ANA), or primary/secondary glaucoma diagnosed by an ophthalmologist; (2) continuously observable during a 36-month lookback period; (3) no history of glaucoma medications, laser, or surgical procedures; and (4) optical coherence tomography (OCT) or visual field performed within 6 months of initial diagnosis. Logistic regression models were developed to identify factors associated with no record of gonioscopy based on Current Procedural Terminology (CPT) codes.

RESULTS

Among 198,995 patients, 20.4% and 29.5% had recorded gonioscopy on the day of diagnosis or within 6 months, respectively. On multivariable analysis, odds of recorded gonioscopy within 6 months of initial evaluation was lower (P < .001) among non-Hispanic Whites (OR=0.84) but similar for Blacks (OR=1.02) and Hispanics (OR=0.96) compared with Asians. Age ≥60 years (OR<0.82), pseudophakia/aphakia (OR=0.58), or residence outside of the Northeast region (OR=0.66-0.84) conferred lower odds of recorded gonioscopy (P < .001). Angle closure glaucoma (OR=0.85), secondary glaucoma (OR=0.31), or open angle glaucoma/suspect (OR=0.12/0.24, respectively) patients were less likely to have recorded gonioscopy compared to ANA patients (P < .01).

CONCLUSIONS

More than 70% patients undergoing initial glaucoma evaluation in the United States do not have a record of gonioscopy, especially elderly, non-Hispanic White, and pseudophakic patients in non-Northeast regions. This pattern does not conform to current practice guidelines and could contribute to misdiagnosed disease and suboptimal outcomes.

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

BACKGROUND

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).

METHODS

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).

RESULTS

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%).

CONCLUSIONS

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.

Automated expert-level scleral spur detection and quantitative biometric analysis on the ANTERION anterior segment OCT system

AIM

To perform an independent validation of deep learning (DL) algorithms for automated scleral spur detection and measurement of scleral spur-based biometric parameters in anterior segment optical coherence tomography (AS-OCT) images.

METHODS

Patients receiving routine eye care underwent AS-OCT imaging using the ANTERION OCT system (Heidelberg Engineering, Heidelberg, Germany). Scleral spur locations were marked by three human graders (reference, expert and novice) and predicted using DL algorithms developed by Heidelberg Engineering that prioritise a false positive rate <4% (FPR4) or true positive rate >95% (TPR95). Performance of human graders and DL algorithms were evaluated based on agreement of scleral spur locations and biometric measurements with the reference grader.

RESULTS

1308 AS-OCT images were obtained from 117 participants. Median differences in scleral spur locations from reference locations were significantly smaller (p<0.001) for the FPR4 (52.6±48.6 µm) and TPR95 (55.5±50.6 µm) algorithms compared with the expert (61.1±65.7 µm) and novice (79.4±74.9 µm) graders. Intergrader reproducibility of biometric measurements was excellent overall for all four (intraclass correlation coefficient range 0.918-0.997). Intergrader reproducibility of the expert grader (0.567-0.965) and DL algorithms (0.746-0.979) exceeded that of the novice grader (0.146-0.929) for images with narrow angles defined by OCT measurement of angle opening distance 500 µm anterior to the scleral spur (AOD500)<150 µm.

CONCLUSIONS

DL algorithms on the ANTERION approximate expert-level measurement of scleral spur-based biometric parameters in an independent patient population. These algorithms could enhance clinical utility of AS-OCT imaging, especially for evaluating patients with angle closure and performing intraocular lens calculations.

Long-term prognosis of acute primary angle closure in an east asian cohort

PURPOSE

To provide an updated analysis of the long-term outcomes of patients with acute primary angle closure (APAC) and to investigate the risk factors for visual field (VF) loss progression.

STUDY DESIGN

Retrospective, clinical cohort study METHODS: One hundred and forty-six APAC patients with a minimum of 1-year follow-up were included. The presenting features and the treatment utilized were recorded. The visual and intraocular pressure (IOP) outcomes were analyzed. The main outcome measures were the proportion of blindness and IOP at the final visit. A subset of patients with sufficient VF results was divided into a stable and progressive group based on mean deviation (MD) loss rate. Univariate and multivariate logistic regression analyses were performed to identify predictors of progression.

RESULTS

Nine patients (6.2%) were blind, and 76.0% (111/146) had final decimal visual acuity greater than or equal to 0.5. All patients had normal final IOP, and 65.1% (95/146) were medication-free. 64.4% (94/146) underwent cataract surgery at a median 4 months after their APAC attack. The use of topical hypotensive medications (OR = 8.029, P = 0.012) was the only significant predictor of fast MD loss in the multivariate regression.

CONCLUSIONS

The long-term outcomes of APAC in recent years have been more promising. All patients maintained normal IOP several years following their APAC attack, and fewer than half required hypotensive agents. The incidence of blindness was low. These findings suggest that current practice patterns in the management of APAC are beneficial.

Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect

Importance

Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS.

Objective

To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC).

Design, Setting, and Participants

This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up.

Results

The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 μm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 μm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 μm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance.

Conclusions and Relevance

This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 μm and light-room ARA at 750 μm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

Anterior Segment OCT for Detection of Narrow Angles: A Community-Based Diagnostic Accuracy Study

PURPOSE

To assess the diagnostic accuracy of anterior segment OCT (AS-OCT) screening for detecting gonioscopically narrow angles.

DESIGN

Population-based cross-sectional study.

PARTICIPANTS

A stratified random sample of individuals aged ≥ 60 years, selected from a door-to-door census performed in low-lying Nepal.

TESTING

Participants underwent AS-OCT, posterior segment OCT, and intraocular pressure (IOP) testing in the community. Those meeting referral criteria in either eye were invited to have a comprehensive eye examination including gonioscopy. Referral criteria included (i) the lowest 2.5% of AS-OCT measurements, (ii) retinal OCT results suggestive of glaucomatous optic neuropathy, diabetic retinopathy, or age-related macular degeneration, and (iii) elevated IOP.

MAIN OUTCOME MEASURES

Sensitivity and specificity of 5 semiautomated AS-OCT parameters relative to gonioscopically narrow angles, defined as the absence of visible trabecular meshwork for ≥ 180° on nonindentation gonioscopy.

RESULTS

Of 17 656 people aged ≥ 60 years enumerated from 102 communities, 12 633 (71.6%) presented for AS-OCT testing. Referral was recommended for 697 participants based on AS-OCT criteria and 2419 participants based on other criteria, of which 858 had gonioscopy performed by a glaucoma specialist. Each of the 5 AS-OCT parameters offered good diagnostic information for predicting eyes with gonioscopically narrow angles, with areas under the receiver operating characteristic curve ranging from 0.85 to 0.89. The angle opening distance at 750 μm from the scleral spur (AOD750) provided the most diagnostic information, providing an optimal sensitivity of 87% (95% confidence interval [CI], 75%-96%) and specificity of 77% (71%-83%) at a cutpoint of 367 μm, and a sensitivity of 65% (95% CI, 54%-74%) when specificity was constrained to 90% (cutpoint, 283 μm).

CONCLUSIONS

On AS-OCT, the AOD750 parameter detected approximately two-thirds of cases of gonioscopically narrow angles when test specificity was set to 90%. Although such a sensitivity may not be sufficient when screening solely for narrow angles, AS-OCT requires little additional effort if posterior segment OCT is already being performed and thus could provide incremental benefit when performing OCT-based screening.

FINANCIAL DISCLOSURE(S)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Anterior Segment Biometry During Accommodation After Posterior Chamber Phakic Implantable Collamer Lens Implantation

PURPOSE

To evaluate the dynamic changes in anterior segment parameters during accommodation following Implantable Collamer Lens (ICL) implantation with swept-source optical coherence tomography (SS-OCT).

METHODS

Under the accommodation of 0.00 diopters (D), 3.00 D, and maximum amplitude, SS-OCT was used to examine the anterior segment parameters, including ICL vault, ICL depth (the distance between the corneal endothelium and the posterior surface of ICL), crystalline lens thickness, anterior chamber depth, and various parameters of the anterior chamber angle, comprising angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle.

RESULTS

During accommodation, the ICL vault showed a significant decrease from baseline (536 ± 278 μm) to 3.00 D (522 ± 281 μm), followed by an increase from 3.00 D to maximum amplitude (548 ± 306 μm) (analysis of variance [ANOVA], P < .001). Four eyes (2.61%) exhibited a decrease in ICL vault to less than 100 μm (47 ± 32 μm) at maximum accommodation. The ICL depth decreased significantly as accommodation increased (ANOVA, P < .001). Crystalline lens thickness increased, whereas anterior chamber depth decreased during accommodation (ANOVA, P < .001). The anterior chamber angle widened during 3.00 D of accommodation but narrowed at maximum accommodation, leading to significant changes in the angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle during accommodation (ANOVA, P < .001 for all).

CONCLUSIONS

The anterior segment, including ICL vault and anterior chamber angle, undergo significant dynamic changes during accommodation. These accommodative changes may require careful monitoring for the surgery design of ICL implantation. [J Refract Surg. 2024;40(3):e164-e172.].

Prevalence and Risk Factors of Blindness Among Primary Angle Closure Glaucoma Patients in the United States: An IRIS Registry Analysis

PURPOSE

To assess the prevalence and risk factors of blindness among patients newly diagnosed with primary angle closure glaucoma (PACG) in the United States.

DESIGN

Retrospective cross-sectional study.

METHODS

Eligible patients from the American Academy of Ophthalmology (AAO) Intelligent Research in Sight (IRIS) Registry had newly diagnosed PACG, defined as: 1) observable during a 24-month lookback period from index date of PACG diagnosis; 2) no history of eye drops, laser, or cataract surgery unless preceded by a diagnosis of anatomical narrow angle (ANA); and 3) no history of glaucoma surgery. Logistic regression models were developed to identify risk factors for any (one or both eyes) or bilateral (both eyes) blindness (visual acuity ≤20/200) at first diagnosis of PACG.

RESULTS

Among 43,901 eligible patients, overall prevalence of any and bilateral blindness were 11.5% and 1.8%, respectively. Black and Hispanic patients were at higher risk of any (odds ratios [ORs] 1.42 and 1.21, respectively; P < .001) and bilateral (ORs 2.04 and 1.53, respectively; P < .001) blindness compared with non-Hispanic White patients adjusted for ocular comorbidities. Age <50 or >80 years, male sex, Medicaid or Medicare insurance product, and Southern or Western practice region also conferred a higher risk of blindness (OR > 1.28; P ≤ .01).

CONCLUSIONS

Blindness affects 1 of 9 patients with newly diagnosed PACG in the IRIS Registry. Black and Hispanic patients and Medicaid and Medicare recipients are at significantly higher risk. These findings highlight the severe ocular morbidity among patients with PACG and the need for improved disease awareness and detection methods.

Iris volume change with physiologic mydriasis to identify development of angle closure: the Zhongshan Angle Closure Prevention Trial

AIMS

To assess dynamic change of iris area (Iarea) and volume (VOL) with physiologic pupil dilation for progression of primary angle closure suspects.

METHODS

Participants underwent baseline examinations including gonioscopy and anterior segment OCT (AS-OCT) as part of the Zhongshan Angle Closure Prevention Trial. The AS-OCT images were obtained both in the dark and light. Progression was defined as development of primary angle closure or an acute angle closure attack. Static ocular biometrics and dynamic changes were compared between progressors and non-progressors and multivariable logistic regression was developed to assess risk factors for progression.

RESULTS

A mean 16.8% decrease in Iarea and a mean 6.26% decrease in VOL occurred with pupil dilation, while 22.96% non-progressors and 40% progressors presented VOL increases with pupil dilation. Iarea in light and dark and VOL in light were significantly smaller in progressors. In a multivariable logistic model, older age (p=0.008), narrower horizontal angle opening distance (AOD) 250 µm from the scleral spur (AOD250, p=0.001), flatter iris curvature (IC, p=0.006) and lower loss of iris volume (ΔVOL, p=0.04) were significantly associated with progression. With receiver operating characteristic analysis, the area under the curve for ΔVOL alone was 0.621, while that for the combined index (age, AOD250, IC and ΔVOL) was 0.824. Eyes with elevated intraocular pressure had less VOL loss compared with progressors developing peripheral anterior synechiae alone (p=0.055 for ΔVOL adjusted for pupil enlargement).

CONCLUSION

A smaller change in ΔVOL is an additive risk factor to identify eyes more likely to develop angle closure disease.

TRIAL REGISTRATION NUMBER

ISRCTN45213099.

Assessment of angle closure disease in the age of artificial intelligence: A review

Primary angle closure glaucoma is a visually debilitating disease that is under-detected worldwide. Many of the challenges in managing primary angle closure disease (PACD) are related to the lack of convenient and precise tools for clinic-based disease assessment and monitoring. Artificial intelligence (AI)- assisted tools to detect and assess PACD have proliferated in recent years with encouraging results. Machine learning (ML) algorithms that utilize clinical data have been developed to categorize angle closure eyes by disease mechanism. Other ML algorithms that utilize image data have demonstrated good performance in detecting angle closure. Nonetheless, deep learning (DL) algorithms trained directly on image data generally outperformed traditional ML algorithms in detecting PACD, were able to accurately differentiate between angle status (open, narrow, closed), and automated the measurement of quantitative parameters. However, more work is required to expand the capabilities of these AI algorithms and for deployment into real-world practice settings. This includes the need for real-world evaluation, establishing the use case for different algorithms, and evaluating the feasibility of deployment while considering other clinical, economic, social, and policy-related factors.

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

PURPOSE

To investigate longitudinal changes in the anterior segment (AS) using serial optical coherence tomography (OCT) images and determine the impact of these changes on the anterior chamber angle (ACA) in eyes with primary angle closure disease (PACD) treated with laser peripheral iridotomy (LPI).

DESIGN

Retrospective clinical cohort study.

METHODS

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).

RESULTS

Multivariate LMEMs showed that decrease in AOD750 was not significant (-1.59 µm/y, P = .222); however, ARA750 decreased over time (-2.3 × 103 µm2/y, P = .033) and SSA showed marginal significance (-0.20°/y, P = .098), and LV increased significantly (11.6 µm/y, P < .001) after LPI. Mean LV change was negatively associated with AOD750, ARA750, and SSA, whereas PD was negatively associated with ARA750 (P < .001 each). PD decreased with aging (-13.7 µm/y, P = .036), accompanied by thinning of IT750 (-1.7 µm/y, P = .063).

CONCLUSIONS

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.

Deep Learning-based Quantification of Anterior Segment OCT Parameters

Objective

To develop and validate a deep learning algorithm that could automate the annotation of scleral spur (SS) and segmentation of anterior chamber (AC) structures for measurements of AC, iris, and angle width parameters in anterior segment OCT (ASOCT) scans.

Design

Cross-sectional study.

Subjects

Data from 2 population-based studies (i.e., the Singapore Chinese Eye Study and Singapore Malay Eye Study) and 1 clinical study on angle-closure disease were included in algorithm development. A separate clinical study on angle-closure disease was used for external validation.

Method

Image contrast of ASOCT scans were first enhanced with CycleGAN. We utilized a heat map regression approach with coarse-to-fine framework for SS annotation. Then, an ensemble network of U-Net, full resolution residual network, and full resolution U-Net was used for structure segmentation. Measurements obtained from predicted SSs and structure segmentation were measured and compared with measurements obtained from manual SS annotation and structure segmentation (i.e., ground truth).

Main Outcome Measures

We measured Euclidean distance and intraclass correlation coefficients (ICC) to evaluate SS annotation and Dice similarity coefficient for structure segmentation. The ICC, Bland-Altman plot, and repeatability coefficient were used to evaluate agreement and precision of measurements.

Results

For SS annotation, our algorithm achieved a Euclidean distance of 124.7 μm, ICC ≥ 0.95, and a 3.3% error rate. For structure segmentation, we obtained Dice similarity coefficient ≥ 0.91 for cornea, iris, and AC segmentation. For angle width measurements, ≥ 95% of data points were within the 95% limits-of-agreement in Bland-Altman plot with insignificant systematic bias (all P > 0.12). The ICC ranged from 0.71-0.87 for angle width measurements, 0.54 for IT750, 0.83-0.85 for other iris measurements, and 0.89-0.99 for AC measurements. Using the same SS coordinates from a human expert, measurements obtained from our algorithm were generally less variable than measurements obtained from a semiautomated angle assessment program.

Conclusion

We developed a deep learning algorithm that could automate SS annotation and structure segmentation in ASOCT scans like human experts, in both open-angle and angle-closure eyes. This algorithm reduces the time needed and subjectivity in obtaining ASOCT measurements.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Treatment Preferences and Factors Influencing the Management of Primary Angle-Closure Suspect in China: A National Survey Study

INTRODUCTION

This study explored the current views of ophthalmologists in China on the preferred strategy and the primary influencing factors in managing primary angle-closure suspect (PACS).

METHODS

An online survey was distributed via WeChat to ophthalmologists working in hospitals at all levels throughout China to investigate the optimal management strategy and factors influencing the strategy for treating PACS from February to March 2023. Management strategies examined included regular observation (RO), laser peripheral iridectomy (LPI), and phacoemulsification with intraocular lens implantation (PEI). The study explored the factors that influenced clinical decision-making processes and collected demographic information from the respondents for analysis.

RESULTS

A total of 1009 ophthalmologists responded; 442 responders considered RO as a reasonable option for patients with PACS, while the majority opted for more positive treatments, with 460 choosing LPI and 107 selecting PEI. Further grouping analysis revealed significant differences between tertiary and lower-level hospitals (P < 0.01) and between public and private hospitals (P < 0.05). Significant differences were found among resident, attending, and senior doctors and between northern and southern hospitals. The top three considerations for ophthalmologists who selected RO were ultrasound biomicroscopy (UBM) without pupillary block, absence of a family history of glaucoma, and good compliance with regular follow-up. For LPI, the factors were UBM indicating pupillary block, glaucoma symptoms, and poor compliance with regular follow-up. For PEI the factors were age, family history of glaucoma, and poor compliance with regular follow-up.

CONCLUSION

The majority of ophthalmologists prefer aggressive treatments such as LPI or PEI over RO when dealing with patients with PACS. Disparity existed among ophthalmologists based on their level of experience, hospital ownership and level, and geographical location. The survey underscores the complexity and multifactorial nature of PACS management and highlights the need for further research and standardization of treatment protocols to ensure optimal patient outcomes.

Deep Learning-Based Model for Automatic Assessment of Anterior Angle Chamber in Ultrasound Biomicroscopy

OBJECTIVE

The goal of the work described here was to develop and assess a deep learning-based model that could automatically segment anterior chamber angle (ACA) tissues; classify iris curvature (I-Curv), iris root insertion (IRI), and angle closure (AC); automatically locate scleral spur; and measure ACA parameters in ultrasound biomicroscopy (UBM) images.

METHODS

A total of 11,006 UBM images were obtained from 1538 patients with primary angle-closure glaucoma who were admitted to the Eye Center of Renmin Hospital of Wuhan University (Wuhan, China) to develop an imaging database. The UNet++ network was used to segment ACA tissues automatically. In addition, two support vector machine (SVM) algorithms were developed to classify I-Curv and AC, and a logistic regression (LR) algorithm was developed to classify IRI. Meanwhile, an algorithm was developed to automatically locate the scleral spur and measure ACA parameters. An external data set of 1,658 images from Huangshi Aier Eye Hospital was used to evaluate the performance of the model under different conditions. An additional 439 images were collected to compare the performance of the model with experts.

RESULTS

The model achieved accuracies of 95.2%, 88.9% and 85.6% in classification of AC, I-Curv and IRI, respectively. Compared with ophthalmologists, the model achieved an accuracy of 0.765 in classifying AC, I-Curv and IRI, indicating that its high accuracy was as high as that of the ophthalmologists (p > 0.05). The average relative errors (AREs) of ACA parameters were smaller than 15% in the internal data sets. Intraclass correlation coefficients (ICCs) of all the angle-related parameters were greater than 0.911. ICC values of all iris thickness parameters were greater than 0.884. The accurate measurement of ACA parameters partly depended on accurate localization of the scleral spur (p < 0.001).

CONCLUSION

The model could effectively and accurately evaluate the ACA automatically based on fully automated analysis of UBM images, and it can potentially be a promising tool to assist ophthalmologists. The present study suggested that the deep learning model can be extensively applied to the evaluation of ACA and AC-related biometric risk factors, and it may broaden the application of UBM imaging in the clinical research of primary angle-closure glaucoma.

Role of Static and Dynamic Ocular Biometrics Measured in the Dark and Light as Risk Factors for Angle Closure Progression

PURPOSE

To assess the role of static and dynamic ocular biometric parameters measured in the dark and light for predicting progression of primary angle closure suspect (PACS) to primary angle closure (PAC).

DESIGN

Retrospective cohort study using prospective randomized controlled trial data from untreated, control eyes.

METHODS

Zhongshan Angle Closure Prevention Trial subjects underwent anterior segment optical coherence tomography (AS-OCT) imaging in the dark and light. Static biometric parameters were measured, consisting of angle, iris, lens, and anterior chamber parameters. Dynamic change parameters were calculated by subtracting light measurements from dark measurements. Cox proportional hazards regression models were developed to assess risk factors for PACD progression.

RESULTS

A total of 861 eyes of 861 participants were analyzed (36 progressors). On univariable analysis, TISA500 measurements in the light and dark were associated with progression (P < .001), whereas dynamic change parameters were not (P ≥ .08). In the primary multivariable model, older age (hazard ratio [HR] = 1.09 per year), higher intraocular pressure (IOP) (HR = 1.13 per mm Hg), and smaller TISA500 in the light (HR = 1.28 per 0.01 mm2) were significantly associated with greater risk of progression (P ≤ .04). Dark TISA500 had similar significance (HR = 1.28, P = .002) when replacing light TISA500. Risk of progression was more predictive among eyes in the lowest quartile of light TISA500 measurements (HR = 4.56, P < .001) compared to dark measurements (HR = 2.89, P = .003).

CONCLUSION

Static parameters measured in the light are as predictive, and possibly more so, of angle closure progression as those measured in the dark. Ocular biometrics measured under light and dark conditions may provide additional information for risk-stratifying patients for angle closure progression.

Rethinking Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects: A Review

PURPOSE

To examine the generalizability, discuss limitations, and critically appraise recommendations on the management of primary angle-closure suspects (PACSs) that emerged as a result of recent randomized clinical trials challenging the widely accepted clinical practice of offering laser peripheral iridotomy (LPI) to PACS patients. To synthetize findings from these and other studies.

DESIGN

Narrative review.

SUBJECTS

Patients classified as PACS.

METHODS

The Zhongshan Angle-Closure Prevention (ZAP)-Trial and the Singapore Asymptomatic Narrow Angle Laser Iridotomy Study (ANA-LIS) along with accompanying publications were reviewed. Epidemiologic studies reporting on the prevalence of primary angle-closure glaucoma and other precursor forms of the disease were also analyzed along with publications reporting on the natural course of the disease or studies reporting on outcomes after prophylactic LPI.

MAIN OUTCOME MEASURES

Incidence of progression to more severe forms of angle closure.

RESULTS

Patients recruited in recent randomized clinical trials are asymptomatic, do not have cataracts, may be younger, and have, on average, deeper anterior chambers depth compared with patients treated with LPI in clinics.

CONCLUSIONS

The ZAP-Trial and ANA-LIS clearly represent the best available data on PACS management, additional parameters however may need to be considered when physicians face patients in clinic. PACS patients encountered at tertiary referral centers may represent more advanced cases with respect to ocular biometric parameters and may be at higher risk for disease progression compared with those recruited through population-based screening.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Machine learning-couched treatment algorithms tailored to individualized profile of patients with primary anterior chamber angle closure predisposed to the glaucomatous optic neuropathy

Background

Primary angle closure glaucoma (PACG) is still one of the leading causes of irreversible blindness, with a trend towards an increase in the number of patients to 32.04 million by 2040, an increase of 58.4% compared with 2013. Health risk assessment based on multi-level diagnostics and machine learning-couched treatment algorithms tailored to individualized profile of patients with primary anterior chamber angle closure are considered essential tools to reverse the trend and protect vulnerable subpopulations against health-to-disease progression.

Aim

To develop a methodology for personalized choice of an effective method of primary angle closure (PAC) treatment based on comparing the prognosis of intraocular pressure (IOP) changes due to laser peripheral iridotomy (LPI) or lens extraction (LE).

Methods

The multi-parametric data analysis was used to develop models predicting individual outcomes of the primary angle closure (PAC) treatment with LPI and LE. For doing this, we suggested a positive dynamics in the intraocular pressure (IOP) after treatment, as the objective measure of a successful treatment. Thirty-seven anatomical parameters have been considered by applying artificial intelligence to the prospective study on 30 (LE) + 30 (LPI) patients with PAC.

Results and data interpretation in the framework of 3P medicine

Based on the anatomical and topographic features of the patients with PAC, mathematical models have been developed that provide a personalized choice of LE or LPI in the treatment. Multi-level diagnostics is the key tool in the overall advanced approach. To this end, for the future application of AI in the area, it is strongly recommended to consider the following:Clinically relevant phenotyping applicable to advanced population screeningSystemic effects causing suboptimal health conditions considered in order to cost-effectively protect affected individuals against health-to-disease transitionClinically relevant health risk assessment utilizing health/disease-specific molecular patterns detectable in body fluids with high predictive power such as a comprehensive tear fluid analysis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00337-1.

Classification of Angle Closure Severity by Hierarchical Cluster Analysis of Ocular Biometrics in the Dark and Light

Purpose

The purpose of this study was to investigate the classification of angle closure eyes based on hierarchical cluster analysis of ocular biometrics measured in the dark and light using anterior segment optical coherence tomography (AS-OCT).

Methods

Participants of the Chinese American Eye Study received complete eye examinations to identify primary angle closure suspects (PACS) and primary angle closure without/with glaucoma (PAC/G). AS-OCT was performed in the dark and light. Biometric parameters describing the angle, iris, lens, and anterior chamber were analyzed. Hierarchical clustering was performed using Ward's method. Post hoc logistic regression models were developed to identify biometric predictors of angle closure staging.

Results

Analysis of 159 eyes with PACS (N = 120) or PAC/G (N = 39) produced 2 clusters in the dark and light. In both analyses, cluster 1 (N = 132 in the dark and N = 126 in the light) was characterized by smaller angle opening distance (AOD)750 and trabecular iris space area (TISA)750, greater iris curvature (IC), and greater lens vault (LV; P < 0.001) than cluster 2. The proportion of PAC/PACG to PACS eyes was significantly higher in cluster 1 than 2 in the light (36:90 and 3:30, respectively; P = 0.02), but not the dark (36:96 and 3:24, respectively; P = 0.08). On multivariable regression analyses, smaller TISA750 (odds ratio [OR] = 0.84 per 0.01 mm2) and AOD750 (OR = 0.93 per 0.01 mm) in the light and smaller TISA750 (OR = 0.86 per 0.01 mm2) in the dark conferred higher risk of PAC/G (P ≤ 0.02).

Conclusions

Unsupervised cluster analysis of ocular biometrics can classify angle closure eyes by severity. Static biometrics measured in the light and dark are both predictive of PAC/G.

Translational Relevance

Clustering of biometrics measured in the light could provide an alternative source of information to risk-stratify angle closure eyes for more severe disease.

Fourteen-Year Outcome of Angle-Closure Prevention with Laser Iridotomy in the Zhongshan Angle-Closure Prevention Study: Extended Follow-up of a Randomized Controlled Trial

PURPOSE

This study aimed to evaluate the efficacy of laser peripheral iridotomy (LPI) prophylaxis for patients with primary angle-closure suspect (PACS) after 14 years and to identify risk factors for the conversion from PACS to primary angle closure (PAC).

DESIGN

Extended follow-up of the Zhongshan Angle-Closure Prevention Study.

PARTICIPANTS

Eight hundred eighty-nine Chinese patients 50 to 70 years of age with bilateral PACS.

METHODS

Each patient received LPI in 1 randomly selected eye, with the fellow untreated eye serving as a control. Because the risk of glaucoma was low and acute angle closure (AAC) occurred only rarely, the follow-up was extended to 14 years despite substantial benefits of LPI reported after the 6-year visit.

MAIN OUTCOME MEASURES

Incidence of PAC, a composite end point including peripheral anterior synechiae, intraocular pressure (IOP) of > 24 mmHg, or AAC.

RESULTS

During the 14 years, 390 LPI-treated eyes and 388 control eyes were lost to follow-up. A total of 33 LPI-treated eyes and 105 control eyes reached primary end points (P < 0.01). Within them, 1 LPI-treated eye and 5 control eyes progressed to AAC. Primary angle-closure glaucoma was found in 2 LPI-treated eyes and 4 control eyes. The hazard ratio for progression to PAC was 0.31 (95% confidence interval, 0.21-0.46) in LPI-treated eyes compared with control eyes. At the 14-year visit, LPI-treated eyes showed more severe nuclear cataract, higher IOP, and larger angle width and limbal anterior chamber depth (LACD) than control eyes. Higher IOP, shallower LACD, and greater central anterior chamber depth (CACD) were associated with an increased risk of end points developing in control eyes. In the treated group, eyes with higher IOP, shallower LACD, or less IOP elevation after the darkroom prone provocative test (DRPPT) were more likely to demonstrate PAC after LPI.

CONCLUIONS

Despite a two-third decrease in PAC occurrence after LPI, the cumulative risk of progression was relatively low in the community-based PACS population over 14 years. Apart from IOP, IOP elevation after DRPPT, CACD, and LACD, more risk factors are needed to achieve precise prediction of PAC occurrence and to guide clinical practice.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Comparison of Lens Extraction Versus Laser Iridotomy on Anterior Segment, Choroid, and Intraocular Pressure in Primary Angle Closure Using Machine Learning

PRCIS

Treatment strategy of primary angle closure (PAC) is not clear due to the large number of clinical and anatomic-topographic parameters in PAC, influencing the treatment algorithm. Using the machine learning method DD-SIMCA, we justify the expediency of early lens extraction (LE) in PAC.

PURPOSE

To compare the anatomic and functional efficacy of LE and laser peripheral iridotomy (LPI) in patients with PAC using Machine Learning.

MATERIALS AND METHODS

This prospective study included 120 patients aged 41-80 years: 60 eyes with PAC, 30 with PAC suspects, and 30 with healthy eyes (control). Thirty PAC eyes with intraocular pressure (IOP) up to 30 mm Hg were treated using LE with intraocular lens implantation and 30 eyes with LPI. All subjects underwent Swept Source optical coherence tomography. We analyzed 35 parameters of each eye including the lens vault, the choroidal thickness, the anterior chamber angle, and iris specifications such as iris curvature. Considering the correlations between them, the machine learning method DD-SIMCA 1-class classification was applied: the proximity of each sample to the target class (control) was characterized by the total distance to it.

RESULTS

After LE, IOP was significantly lower than after LPI ( P =0). Every third eye with PAC after LE reached the target class: specificity according to DD-SIMCA equals 0.67. This was not observed for the eyes after LPI: specificity equals 1.0. After LE, all parameters of the anterior chamber angle did not differ from the control (all P >0.05). After LPI, there was an increase in anterior chamber depth ( P =0) and a decrease in lens vault ( P =0), but results comparable to the control were achieved only for iris curvature ( P =1.000).

CONCLUSION

The efficacy of LE in PAC is higher than LPI due to the better postoperative anterior chamber topography and lower IOP. This study lends further clinical and anatomic support to the emerging notion of LE as an effective treatment for PAC.

Biometric Risk Factors for Angle Closure Progression After Laser Peripheral Iridotomy

Importance

Laser peripheral iridotomy (LPI) is the most common primary treatment for primary angle closure disease (PACD). However, there are sparse data guiding the longitudinal care of PAC suspect (PACS) eyes after LPI.

Objective

To elucidate the anatomic effects of LPI that are associated with a protective outcome against progression from PACS to PAC and acute angle closure (AAC) and to identify biometric factors that predict progression after LPI.

Design, Setting, and Participants

This was a retrospective analysis of data from the Zhongshan Angle Closure Prevention (ZAP) trial, a study of mainland Chinese people aged 50 to 70 years with bilateral PACS who received LPI in 1 randomly selected eye. Gonioscopy and anterior-segment optical coherence tomography (AS-OCT) imaging were performed 2 weeks after LPI. Progression was defined as the development of PAC or an acute angle closure (AAC) attack. Cohort A included a random mix of treated and untreated eyes, and cohort B included only eyes treated with LPI. Univariable and multivariable Cox regression models were developed to assess biometric risk factors for progression in cohorts A and B. Data were analyzed from January 4 to December 22, 2022.

Main Outcome and Measure

Six-year progression to PAC or AAC.

Results

Cohort A included 878 eyes from 878 participants (mean [SD] age, 58.9 [5.0] years; 726 female [82.7%]) of whom 44 experienced progressive disease. In a multivariable analysis, treatment (hazard ratio [HR], 0.67; 95% CI, 0.34-1.33; P = .25) was no longer associated with progression after adjusting for age and trabecular iris space area at 500 μm (TISA at 500 μm) at the 2-week visit. Cohort B included 869 treated eyes from 869 participants (mean [SD] age, 58.9 [5.0] years; 717 female [82.5%]) of whom 19 experienced progressive disease. In multivariable analysis, TISA at 500 μm (HR, 1.33 per 0.01 mm2 smaller; 95% CI, 1.12-1.56; P = .001) and cumulative gonioscopy score (HR, 1.25 per grade smaller; 95% CI, 1.03-1.52; P = .02) at the 2-week visit were associated with progression. Persistent angle narrowing on AS-OCT (TISA at 500 μm ≤0.05 mm2; HR, 9.41; 95% CI, 3.39-26.08; P <.001) or gonioscopy (cumulative score ≤6; HR, 2.80; 95% CI, 1.13-6.93; P =.04) conferred higher risk of progression.

Conclusions and Relevance

Study results suggest that persistent angle narrowing detected by AS-OCT or cumulative gonioscopy score was predictive of disease progression in PACS eyes after LPI. These findings suggest that AS-OCT and gonioscopy may be performed to identify patients at high risk of developing angle closure who may benefit from closer monitoring despite patent LPI.

Deep Learning-Based Classification of Subtypes of Primary Angle-Closure Disease With Anterior Segment Optical Coherence Tomography

PRCIS

We developed a deep learning-based classifier that can discriminate primary angle closure suspects (PACS), primary angle closure (PAC)/primary angle closure glaucoma (PACG), and also control eyes with open angle with acceptable accuracy.

PURPOSE

To develop a deep learning-based classifier for differentiating subtypes of primary angle closure disease, including PACS and PAC/PACG, and also normal control eyes.

MATERIALS AND METHODS

Anterior segment optical coherence tomography images were used for analysis with 5 different networks including MnasNet, MobileNet, ResNet18, ResNet50, and EfficientNet. The data set was split with randomization performed at the patient level into a training plus validation set (85%), and a test data set (15%). Then 4-fold cross-validation was used to train the model. In each mentioned architecture, the networks were trained with original and cropped images. Also, the analyses were carried out for single images and images grouped on the patient level (case-based). Then majority voting was applied to the determination of the final prediction.

RESULTS

A total of 1616 images of normal eyes (87 eyes), 1055 images of PACS (66 eyes), and 1076 images of PAC/PACG (66 eyes) eyes were included in the analysis. The mean ± SD age was 51.76 ± 15.15 years and 48.3% were males. MobileNet had the best performance in the model, in which both original and cropped images were used. The accuracy of MobileNet for detecting normal, PACS, and PAC/PACG eyes was 0.99 ± 0.00, 0.77 ± 0.02, and 0.77 ± 0.03, respectively. By running MobileNet in a case-based classification approach, the accuracy improved and reached 0.95 ± 0.03, 0.83 ± 0.06, and 0.81 ± 0.05, respectively. For detecting the open angle, PACS, and PAC/PACG, the MobileNet classifier achieved an area under the curve of 1, 0.906, and 0.872, respectively, on the test data set.

CONCLUSION

The MobileNet-based classifier can detect normal, PACS, and PAC/PACG eyes with acceptable accuracy based on anterior segment optical coherence tomography images.

Rates and Patterns of Diagnostic Conversion from Anatomical Narrow Angle to Primary Angle-Closure Glaucoma in the United States

PURPOSE

To assess rates of diagnostic conversion from anatomical narrow angle (ANA) to primary angle-closure glaucoma (PACG) in the United States and identify factors associated with diagnostic conversion.

DESIGN

Retrospective case-control study.

PARTICIPANTS

Patients diagnosed with ANA between the years 2007 and 2019 were identified based on International Classification of Diseases (ICD) codes in the Optum Clinformatics Data Mart Database. Inclusion was limited to newly diagnosed ANA, defined as the following: (1) continuous enrollment during a 2-year look back period and 6-year study period from index (first) date of ANA diagnosis; (2) diagnosis by an ophthalmologist or optometrist and record of gonioscopy; and (3) no history of intraocular pressure (IOP)-lowering drops, laser peripheral iridotomy (LPI), or intraocular surgery.

METHODS

Cox proportional hazards models were developed to assess factors associated with diagnostic conversion, defined as a change in ICD code from ANA to PACG.

MAIN OUTCOME MEASURES

New diagnosis of PACG within the 6-year study period recorded after an index diagnosis of ANA.

RESULTS

Among 3985 patients meeting inclusion criteria, 459 (11.52%) had detected diagnostic conversion to PACG within the study period. The conversion rate was stable at 3.54% per year after the first 6 months of ANA diagnosis. In the Cox proportional hazards model, age > 70 years and early (within 6 months of ANA diagnosis) need for LPI or IOP-lowering drops were positively associated with diagnostic conversion (hazard ratio [HR] > 1.59; P < 0.02). Cataract surgery at any time and late (after 6 months of ANA diagnosis) need for IOP-lowering drops appeared protective against diagnostic conversion (HR < 0.46; P < 0.004).

CONCLUSIONS

Annual risk of diagnostic conversion from ANA to PACG is relatively low overall; elderly patients are at higher risk whereas patients receiving cataract surgery are at lower risk. The utility of long-term monitoring seems low for most patients with ANA, highlighting the need for improved clinical methods to identify patients at higher risk for PACG.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Predictors of long-term visual field outcome after an episode of acute primary angle closure

BACKGROUND

To investigate the long-term visual field (VF) outcome and baseline factors associated with functional sequelae in patients who experienced an episode of acute primary angle closure (APAC) and underwent subsequent lens extraction.

METHODS

Fifty patients (50 eyes) who experienced an APAC episode and underwent subsequent lens extraction at Chonnam National University Hospital were enrolled in this retrospective study. Patients underwent VF examinations after 1 year of an acute episode. They were classified into two groups based on whether they had significant VF defects or not. Demographic data were recorded, and baseline anterior-segment OCT (AS-OCT) images were analysed. Multivariate logistic regression analysis was performed to assess baseline risk factors for presence of VF defects.

RESULTS

Twenty-five (50%) eyes were found to have varied degree of VF defects after 1 year of an acute episode. Longer duration between the symptom onset and IOP lowering (p = 0.005), a higher presenting IOP (p = 0.014), and flat iris curvature (p = 0.037) at baseline AS-OCT measurement were significant predictors of VF loss. The area under the receiver operating characteristic curve (AUC) revealed that combination of these three potential baseline factors could predict the long-term VF outcome (AUC = 0.921).

CONCLUSIONS

Patients exhibiting a long duration between symptom onset and IOP lowering, a high presenting IOP, and flat iris curvature were at a higher risk of visual impairment after an episode of APAC. The eyes with such features may require more careful follow-up after an episode of APAC.

Assessment of Iris Trabecular Contact in Eyes with Gonioscopic Angle-Closure

PURPOSE

To investigate the extent of iris trabecular contact (ITC) measured by anterior segment OCT (AS-OCT) and its association with primary angle-closure (PAC) and PAC glaucoma (PACG) in eyes with gonioscopic angle-closure and to determine the diagnostic performance of ITC for detection of gonioscopic angle-closure.

DESIGN

Multicenter, prospective study.

PARTICIPANTS

A total of 119 healthy participants with gonioscopic open-angle and 170 patients with gonioscopic angle-closure (94 with PAC suspect and 76 with PAC/PACG) were included.

METHODS

One eye of each subject was randomly selected for AS-OCT imaging. Angle-opening distance (AOD500) and trabecular iris space area (TISA500) were measured every 10° for 360°. Two criteria of ITC500 were examined: (1) AOD500 = 0 mm and (2) TISA500 = 0 mm². The association between the extent of ITC500 and PAC/PACG in eyes with gonioscopic angle-closure was analyzed with logistic regression analysis.

MAIN OUTCOME MEASURES

Sensitivity and specificity of ITC500 for detection of gonioscopic angle-closure; odds ratio (OR) of PAC/PACG.

RESULTS

The sensitivity of ITC500 ≥ 10° for detection of gonioscopic angle-closure ranged from 82.4% (AOD500 = 0 mm) to 84.7% (TISA500 = 0 mm²), and the specificity was 85.7% (for both AOD500 = 0 mm and TISA500 = 0 mm²). The extent of ITC500 determined by AS-OCT, not cumulative gonioscopy score (i.e., the sum of the modified Shaffer grades over 4 quadrants), was associated with the odds of PAC/PACG in eyes with gonioscopic angle-closure; the odds of PAC/PACG increased by 5% for every 10° increase in ITC500 (OR, 1.051, 95% confidence interval [CI], 1.022-1.080 for AOD500 = 0 mm; OR, 1.049, 95% CI, 1.022-1.078 for TISA500 = 0 mm²). Axial length and anterior chamber depth were not associated with PAC/PACG in eyes with gonioscopic angle-closure (P ≥ 0.574).

CONCLUSIONS

A greater extent of ITC measured by AS-OCT, not angle-closure determined by gonioscopy, was associated with a greater odds of PAC/PACG in eyes with gonioscopic angle-closure.

Detecting eyes with high risk of angle closure among apparently normal eyes by anterior segment OCT: a health examination center-based model

BACKGROUND

The main barriers keeping individuals with high-risk of angle closure from seeking eye-care service are the absence of both disease awareness and convenient and low-cost access to the ocular health care system. Present study described the efficacy of a health examination center-based screening model designed to detect eyes with high risk of angle closure (HRAC) among healthy individuals using anterior segment optical coherence tomography (AS-OCT).

METHODS

From March 1 to April 30, 2017, consecutive individuals aged ≥ 40 years undergoing routine physical examinations at a health examination center were invited to enroll. Presenting visual acuity (PVA), intraocular pressure (IOP) measurement, non-mydriatic fundus photography and AS-OCT were performed by three trained nurses. Participants with PVA < 6/12 in the better-seeing eye, IOP ≥ 24 mmHg, or abnormal fundus photography in either eye were referred to the outpatient clinic, but not included in the analysis. Eyes with HRAC were defined as having trabecular-iris angle < 12 degrees in ≥ 3 quadrants. Configuration of the iris was classified into flat, bowing, bombe, thick peripheral iris and mixed mechanism.

RESULTS

Altogether, 991 participants (77.3%) with readable OCT images (mean age 55.5 ± 9.0 years; 58.4% men) were included. HRAC was diagnosed in 78 eyes (7.9%, 61.3 ± 8.2 years, 41.0% men). The prevalence of HRAC increased with age (p < 0.001) and was much higher among women (11.2%) than men (5.5%) (p = 0.001). The mixed mechanism iris configuration was most common among eyes with HRAC (37/78, 47.4%).

CONCLUSION

HRAC is prevalent among asymptomatic Chinese adults undergoing routine health screening. Health examination center-based eye screening with AS-OCT administered by non-specialists may be a good model to screen narrow angles in the population at large.

Age-Related Changes in Dynamic Iris Behavior Assessed Using a Programmable Closed-Loop Iris Control System

Purpose

The purpose of this study was to develop and test a programmable closed-loop system for tracking, modulating, and assessing dynamic iris behavior, including in the mid-dilated position.

Methods

A programmable closed-loop iris control system was developed by customizing an ANTERION OCT device (Heidelberg Engineering, Heidelberg, Germany). Custom software was developed to store camera and optical coherence tomography (OCT) images, track pupillary diameter (PD), control a light-emitting diode (LED), and modulate ambient lighting to maintain the iris in a dilated, constricted, or mid-dilated position in real-time. Study participants underwent 3 consecutive 65-second scan sessions. Dynamic iris behavior in the form of peak constriction velocity (PCV) and mid-dilated iris activity (MDIA) were calculated and analyzed offline.

Results

Among 58 participants, 56 (96.6%) were eligible for analysis based on achieving and maintaining mean PD within ±10% of the calculated mid-dilated PD. Mean participant age was 49.8 ± 18.9 years. Mean PCV was 3.92 ± 0.83 mm/s, and mean MDIA was 0.37 ± 0.15 mm. The mean difference between the calculated and achieved mid-dilated PD was 0.166 ± 0.192 mm. There were significant negative correlations between PCV and age (slope = -0.022, P < 0.001) and MDIA and age (slope = -0.004, P < 0.001). Success rates were lower (69.0%) but relationships between dynamic iris behavior and age were similar based on achieving and maintaining mean PD within ±5% of the calculated mid-dilated PD.

Conclusions

A programmable closed-loop iris control system can modulate dynamic iris behavior and maintain the iris in a mid-dilated position. Pupillary constriction velocity and iris activity in the mid-dilated position decrease with age.

Translational Relevance

This system can be applied to study dynamic disease processes involving the iris and establish novel biometric measures that could serve as risk factors for acute and chronic primary angle closure glaucoma (PACG).

[Angle-closure glaucoma]

Angle-closure glaucoma is a rare form of glaucoma characterized by a narrow or an occlusion of the anterior chamber angle and subsequently an obstruction of the outflow of aqueous humor resulting in an increase in intraocular pressure. Symptoms can include severe eye pain and/or headache, blurred vision, a medium-sized and rigid pupil, conjunctival hyperemia, and nausea. Treatment options include pressure-lowering topical and systemic medications as well as surgical interventions, especially cataract surgery and laser iridotomy. Besides parasympathomimetics (pilocarpine), all topical antiglaucoma medications can principally be used (beta-receptor antagonists, carbonic anhydrase inhibitors, alpha‑2 selective adrenergic antagonists, prostaglandins and prostaglandin analogues). Carbonic anhydrase inhibitors and osmotic agents (e.g., mannitol) can be systemically used.

Racial and Sociodemographic Disparities in the Detection of Narrow Angles before Detection of Primary Angle-Closure Glaucoma in the United States

PURPOSE

To assess the proportion of newly diagnosed cases of primary angle-closure glaucoma (PACG) with and without prior diagnosis of anatomical narrow angle (ANA) and to identify sociodemographic risk factors for late detection (PACG without prior ANA diagnosis).

DESIGN

Retrospective cohort study.

METHODS

One hundred two thousand six hundred seventeen patients with PACG were identified from the Optum Clinformatics Data Mart Database (2007-2019). Patients with newly diagnosed PACG met the following criteria: (1) diagnosis made by an ophthalmologist, (2) disease observable for at least 12 months before diagnosis, and (3) no history of treatment before diagnosis unless preceded by a diagnosis of ANA. Multivariate logistic regression modeling was performed to identify sociodemographic risk factors for late detection.

MAIN OUTCOME MEASURES

Proportion of patients with newly diagnosed PACG without prior ANA diagnosis and sociodemographic factors associated with late detection.

RESULTS

Thirty-one thousand forty-four patients were eligible. More than 70% of PACG cases were detected without prior ANA diagnosis, regardless of patient age, sex, or race. The odds of late detection were significantly higher (P < 0.001) among men (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.25-1.40), Black patients (OR, 1.25; 95% CI, 1.15-1.37), and patients 80 years of age or older (OR, 1.28; 95% CI, 1.11-1.47) or living in Southern (OR, 1.30; 95% CI, 1.22-1.40) or Pacific (OR, 1.27; 95% CI, 1.16-1.36) regions. Findings were similar for patients with PACG with a record of gonioscopy and treatment or with a 24-month lookback period.

CONCLUSIONS

Most patients who receive a new diagnosis of PACG in the United States do not have a prior diagnosis of ANA. The elderly, men, and Black patients are at higher risk of late detection. A need exists for increased disease awareness among providers and more accessible tools to detect patients at risk of developing PACG.

[Primary anterior chamber angle closure: progression from suspect to glaucoma. Part 2. Predictors of primary angle closure]

To review the literature devoted to the search of predictors of primary angle closure (PAC) progression as an important link in the pathogenesis of primary angle-closure glaucoma. This part presents a cluster analysis, describes the mechanisms of PAC development, and considers the studies aimed at discovering the risk factors for the progression of primary angle closure suspect into true angle closure. The results of the analyzed literature are ambiguous, indicating the need for further research that would involve strict inclusion criteria, and a standard approach to defining the primary angle closure disease and expanding the diagnostic parameters, in which a key role belongs to anterior segment optical coherence tomography (AS-OCT).