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.

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.

A multicentre analysis of nucleic acid quantification using aqueous humour liquid biopsy in uveal melanoma: implications for clinical testing

OBJECTIVE

Uveal melanoma (UM) tumour biopsy is limited by size and intratumour heterogeneity. We explored the potential of aqueous humour (AH) liquid biopsy for UM by quantifying analytes in samples collected at diagnosis and after brachytherapy to look for clinical correlations with tumour features.

DESIGN

Case-series study.

PARTICIPANTS

Sixty-six UM patients and 16 control subjects from a tertiary care hospital.

METHODS

The study included 119 UM AH samples and 16 control samples analyzed for unprocessed analytes (i.e., dsDNA, miRNA, and protein) using Qubit fluorescence assays.

RESULTS

Analytes were widely quantifiable among available UM AH samples (dsDNA: 94.1%; miRNA: 88.0%; protein: 95.2%) at significantly higher concentrations than among control samples (dsDNA, p = 0.008; miRNA, p < 0.0001; protein, p = 0.007). In samples taken at diagnosis, concentrations were higher at more advanced American Joint Cancer Commission stages; when comparing most advanced stage III with least advanced stage I, median dsDNA was 4 times greater (p < 0.0001), miRNA was 2 times greater (p = 0.001), and protein was 3 times greater (p < 0.0001). Analytes were quantifiable in >70% of diagnostic samples from eyes with tumours <2 mm tall. Height had a positive association with diagnostic analyte concentrations (dsDNA: R = 0.43, p = 0.0007; miRNA: R = 0.35, p = 0.01; protein: R = 0.39, p = 0.005). Samples taken after brachytherapy showed significantly higher concentrations than diagnostic samples (p < 0.01 for all).

CONCLUSIONS

UM AH is a rich repository of analytes. Samples from eyes with more advanced stage and larger tumours had higher concentrations, though analytes also were quantifiable in eyes with smaller, less advanced tumours. Future analysis of AH analytes may be informative in the pursuit of personalized UM treatments.

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.

Investigating the determinants of iridolenticular contact area: a novel parameter for angle closure

BACKGROUND/AIMS

To identify ocular determinants of iridolenticular contact area (ILCA), a recently introduced swept-source optical coherence tomography (SSOCT) derived parameter, and assess the association between ILCA and angle closure.

METHODS

In this population-based cross-sectional study, right eyes of 464 subjects underwent SSOCT (SS-1000, CASIA, Tomey Corporation, Nagoya, Japan) imaging in the dark. Eight out of 128 cross-sectional images (evenly spaced 22.5° apart) were selected for analysis. Matlab (Matworks, Massachusetts, USA) was used to measure ILCA, defined as the circumferential extent of contact area between the pigmented iris epithelium and anterior lens surface. Gonioscopic angle closure (GAC) was defined as non-visibility of the posterior trabecular meshwork in two or more angle quadrants.

RESULTS

The mean age of subjects was 62±6.6 years, with the majority being female (65.5%). 143/464 subjects (28.6%) had GAC. In multivariable linear regression analysis, ILCA was significantly associated with anterior chamber width (β=1.03, p=0.003), pupillary diameter (β=-1.9, p<0.001) and iris curvature (β=-17.35, p<0.001). ILCA was smaller in eyes with GAC compared with those with open angles (4.28±1.6 mm2 vs 6.02±2.71 mm2, p<0.001). ILCA was independently associated with GAC (β=-0.03, p<0.001), iridotrabecular contact index (β=-6.82, p<0.001) or angle opening distance (β=0.02, p<0.001) after adjusting for covariates. The diagnostic performance of ILCA for detecting GAC was acceptable (AUC=0.69).

CONCLUSIONS

ILCA is a significant predictor of angle closure independent of other biometric factors and may reflect unique anatomical information associated with pupillary block. ILCA represents a novel biometric risk factor in eyes with angle closure.

Identifying, Understanding, and Addressing Disparities in Glaucoma Care in the United States

Glaucoma is the leading cause of irreversible blindness worldwide, currently affecting around 80 million people. Glaucoma prevalence is rapidly rising in the United States due to an aging population. Despite recent advances in the diagnosis and treatment of glaucoma, significant disparities persist in disease detection, management, and outcomes among the diverse patient populations of the United States. Research on disparities is critical to identifying, understanding, and addressing societal and healthcare inequalities. Disparities research is especially important and impactful in the context of irreversible diseases such as glaucoma, where earlier detection and intervention are the primary approach to improving patient outcomes. In this article, we first review recent studies identifying disparities in glaucoma care that affect patient populations based on race, age, and gender. We then review studies elucidating and furthering our understanding of modifiable factors that contribute to these inequities, including socioeconomic status (particularly age and education), insurance product, and geographic region. Finally, we present work proposing potential strategies addressing disparities in glaucoma care, including teleophthalmology and artificial intelligence. We also discuss the presence of non-modifiable factors that contribute to differences in glaucoma burden and can confound the detection of glaucoma disparities.

Translational Relevance

By recognizing underlying causes and proposing potential solutions, healthcare providers, policymakers, and other stakeholders can work collaboratively to reduce the burden of glaucoma and improve visual health and clinical outcomes in vulnerable patient populations.

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.

[Efficacy of polyetheretherketone rod hybrid surgery in preventing proximal junctional failure after adult spinal deformity surgery]

Objective: To investigate the clinical outcome and preventive effect of polyetheretherketone(PEEK) rod hybrid surgery on proximal junction failure(PJF) after long-segment fusion of adult spinal deformity. Methods: A retrospective study was conducted to analyze patients with degenerative scoliosis/kyphosis who underwent long-segment decompression and fusion surgery at Department of Orthopedics, Peking University First Hospital from January 2017 to December 2021. A total of 75 patients were included in the study, including 14 males and 61 females, aged (67.2±6.8)years (range:55 to 84 years). According to the operation method chosen by the patients, the patients were divided into PEEK rod hybrid group (20 cases) and traditional titanium rod group (55 cases). The general information of the patients was collected, and the coronal and sagittal parameters of the spine were measured before operation, at 1 month after operation, and at the last follow-up. The clinical effect of surgery was judged by the visual analogue scale (VAS) and Oswestry disability index (ODI). Whether proximal junctional kyphosis (PJK) and PJF occurred during the follow-up and the time of occurrence were recorded. Comparisons between groups were performed using independent sample t test, Mann-Whitney U test, χ2 test and Fisher's exact probability method. The data before and after surgery in the same group were compared using the paired sample t test and the Wilcoxon test. Results: There were no significant differences in age, gender, body mass index, bone mineral density, distal instrumented vertebrae, surgical segments, osteotomy method, operation time, and intraoperative bleeding between the two groups (all P>0.05). The follow-up time of the PEEK rod group was shorter(M(IQR)16.5(4.8) vs. 25.0(12.0),Z=-4.230,P<0.01). There were no significant differences in coronal, sagittal parameters, VAS and ODI between the two groups before operation (all P>0.05). Postoperative coronal Cobb angle, pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, thoracic kyphosis, sagittal vertical axis (SVA), VAS and ODI were significantly improved in both groups(all P<0.05). At the last follow-up, the SVA of the PEEK rod hybrid group was(3.74±2.40)cm, which was significantly lower than that of the titanium rod group (6.28±4.06)cm (t'=-3.318, P=0.002). At the last follow-up, the ODI of the PEEK rod hybrid group was 30.7±6.1, significantly better than the titanium rod group 39.3±17.2(t=-3.203, P=0.046). PJK occurred in 2 patients (10.0%) in the PEEK rod hybrid group, and no PJF phenomenon was observed. In the titanium rod group, 18 patients (32.7%) developed PJK, and 11 patients (20.0%) developed PJF. There was a statistically significant difference in the incidence of PJF between the PEEK rod hybrid group and the titanium rod group (P=0.031). Conclusions: PEEK rod hybrid surgery can achieve good clinical results in the treatment of adult spinal deformities. Compared with traditional titanium rod surgery, it can significantly reduce the incidence of postoperative PJF and improve the clinical function of patients.

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.

Racial and Ethnic Differences in the Roles of Myopia and Ocular Biometrics as Risk Factors for Primary Open-Angle Glaucoma

Purpose

Assess how the roles of refractive error (RE) and ocular biometrics as risk factors for primary open-angle glaucoma (POAG) differ by race and ethnicity.

Methods

Data from the Los Angeles Latino Eye Study (LALES) and the Chinese American Eye Study (CHES), two population-based epidemiological studies, were retrospectively analyzed. Multivariable logistic regression and interaction term analyses were performed to assess relationships between POAG and its risk factors, including RE and axial length (AL), and to assess effect modification by race/ethnicity.

Results

Analysis included 7601 phakic participants of LALES (47.3%) and CHES (52.7%) with age ≥ 50 years. Mean age was 60.6 ± 8.3 years; 60.9% were female. The prevalence and unadjusted risk of POAG were higher in LALES than CHES (6.0% and 4.0%, respectively; odds ratio [OR] = 1.55; P < 0.001). In the multivariable analysis, significant risk factors for POAG included Latino ethnicity (OR = 2.25; P < 0.001), refractive myopia (OR = 1.54 for mild, OR = 2.47 for moderate, OR = 3.94 for high compared to non-myopes; P ≤ 0.003), and longer AL (OR = 1.37 per mm; P < 0.001). AL (standardized regression coefficient [SRC] = 0.3) was 2.7-fold more strongly associated with POAG than high myopia status (SRC = 0.11). There was no modifying effect by race/ethnicity on the association between RE (per diopter) or AL (per millimeter) and POAG (P = 0.49).

Conclusions

Although the POAG risk conferred by myopic RE and longer AL is similar between Latino and Chinese Americans, the difference in POAG prevalence between the two groups is narrowed by higher myopia prevalence among Chinese Americans. Racial/ethnic populations with higher myopia incidence may become disproportionately affected by POAG in the context of the global myopia epidemic.

Refractive Error and Anterior Chamber Depth as Risk Factors in Primary Angle Closure Disease: The Chinese American Eye Study

PRCIS

The risk of primary angle closure disease (PACD) rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Refractive error (RE) is useful for angle closure risk stratification in the absence of biometric data.

PURPOSE

To assess the role of RE and anterior chamber depth (ACD) as risk factors in PACD.

METHODS

Chinese American Eye Study participants received complete eye examinations including refraction, gonioscopy, amplitude-scan biometry, and anterior segment ocular coherence tomography imaging. PACD included primary angle closure suspect (≥3 quadrants of angle closure on gonioscopy) and primary angle closure/primary angle closure glaucoma (peripheral anterior synechiae or intraocular pressure >21 mm Hg). Logistic regression models were developed to assess associations between PACD and RE and/or ACD adjusted for sex and age. Locally weighted scatterplot smoothing curves were plotted to assess continuous relationships between variables.

RESULTS

Three thousand nine hundred seventy eyes (3403 open angle and 567 PACD) were included. The risk of PACD increased with greater hyperopia [odds ratio (OR) = 1.41 per diopter (D); P < 0.001] and shallower ACD (OR = 1.75 per 0.1 mm; P < 0.001). Hyperopia (≥ + 0.5 D; OR = 5.03) and emmetropia (-0.5 D to +0.5 D; OR = 2.78) conferred a significantly higher risk of PACD compared with myopia (≤0.5 D). ACD (standardized regression coefficient = -0.54) was a 2.5-fold stronger predictor of PACD risk compared with RE (standardized regression coefficient = 0.22) when both variables were included in one multivariable model. The sensitivity and specificity of a 2.6 mm ACD cutoff for PACD were 77.5% and 83.2% and of a +2.0 D RE cutoff were 22.3% and 89.1%.

CONCLUSION

The risk of PACD rises rapidly with greater hyperopia while remaining relatively low for all degrees of myopia. Although RE is a weaker predictor of PACD than ACD, it remains a useful metric to identify patients who would benefit from gonioscopy in the absence of biometric data.

Generalisability and performance of an OCT-based deep learning classifier for community-based and hospital-based detection of gonioscopic angle closure

PURPOSE

To assess the generalisability and performance of a deep learning classifier for automated detection of gonioscopic angle closure in anterior segment optical coherence tomography (AS-OCT) images.

METHODS

A convolutional neural network (CNN) model developed using data from the Chinese American Eye Study (CHES) was used to detect gonioscopic angle closure in AS-OCT images with reference gonioscopy grades provided by trained ophthalmologists. Independent test data were derived from the population-based CHES, a community-based clinic in Singapore, and a hospital-based clinic at the University of Southern California (USC). Classifier performance was evaluated with receiver operating characteristic curve and area under the receiver operating characteristic curve (AUC) metrics. Interexaminer agreement between the classifier and two human examiners at USC was calculated using Cohen's kappa coefficients.

RESULTS

The classifier was tested using 640 images (311 open and 329 closed) from 127 Chinese Americans, 10 165 images (9595 open and 570 closed) from 1318 predominantly Chinese Singaporeans and 300 images (234 open and 66 closed) from 40 multiethnic USC patients. The classifier achieved similar performance in the CHES (AUC=0.917), Singapore (AUC=0.894) and USC (AUC=0.922) cohorts. Standardising the distribution of gonioscopy grades across cohorts produced similar AUC metrics (range 0.890-0.932). The agreement between the CNN classifier and two human examiners (Ҡ=0.700 and 0.704) approximated interexaminer agreement (Ҡ=0.693) in the USC cohort.

CONCLUSION

An OCT-based deep learning classifier demonstrated consistent performance detecting gonioscopic angle closure across three independent patient populations. This automated method could aid ophthalmologists in the assessment of angle status in diverse patient populations.

Anterior segment biometric measurements explain misclassifications by a deep learning classifier for detecting gonioscopic angle closure

BACKGROUND/AIMS

To identify biometric parameters that explain misclassifications by a deep learning classifier for detecting gonioscopic angle closure in anterior segment optical coherence tomography (AS-OCT) images.

METHODS

Chinese American Eye Study (CHES) participants underwent gonioscopy and AS-OCT of each angle quadrant. A subset of CHES AS-OCT images were analysed using a deep learning classifier to detect positive angle closure based on manual gonioscopy by a reference human examiner. Parameter measurements were compared between four prediction classes: true positives (TPs), true negatives (TNs), false positives (FPs) and false negatives (FN). Logistic regression models were developed to differentiate between true and false predictions. Performance was assessed using area under the receiver operating curve (AUC) and classifier accuracy metrics.

RESULTS

584 images from 127 participants were analysed, yielding 271 TPs, 224 TNs, 77 FPs and 12 FNs. Parameter measurements differed (p<0.001) between prediction classes among anterior segment parameters, including iris curvature (IC) and lens vault (LV), and angle parameters, including angle opening distance (AOD). FP resembled TP more than FN and TN in terms of anterior segment parameters (steeper IC and higher LV), but resembled TN more than TP and FN in terms of angle parameters (wider AOD). Models for detecting FP (AUC=0.752) and FN (AUC=0.838) improved classifier accuracy from 84.8% to 89.0%.

CONCLUSIONS

Misclassifications by an OCT-based deep learning classifier for detecting gonioscopic angle closure are explained by disagreement between anterior segment and angle parameters. This finding could be used to improve classifier performance and highlights differences between gonioscopic and AS-OCT definitions of angle closure.

[Influence of antimicrobial peptide biofunctionalized TiO2 nanotubes on the biological behavior of human keratinocytes and its antibacterial effect]

Objective: To fabricate TiO2 nanotube material functionalized by antimicrobial peptide LL-37, and to explore its effects on biological behaviors such as adhesion and migration of human keratinocytes (HaCaT) and its antibacterial properties. Methods: The TiO2 nanotube array (NT) was constructed on the surface of polished titanium (PT) by anodization, and the antimicrobial peptide LL-37 was loaded on the surface of TiO2 nanotube (LL-37/NT) by physical adsorption. Three samples were selected by simple random sampling in each group. Surface morphology, roughness, hydrophilicity and release characteristics of LL-37 of the samples were analyzed with a field emission scanning electron microscope, an atomic force microscope, a contact angle measuring device and a microplate absorbance reader. HaCaT cells were respectively cultured on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of cell was observed by field emission scanning electron microscope. The number of cell adhesion was observed by cellular immunofluorescence staining. Cell counting kit-8 (CCK-8) assay was used to detect cell proliferation. Wound scratch assay was used to observe the migration of HaCaT. The above experiments were used to evaluate the effect of each group on the biological behavior of HaCaT cells. To evaluate their antibacterial effects, Porphyromonas gingivalis (Pg) was respectively inoculated on the surface of three groups of titanium samples. Each group had 3 replicates. The morphology of bacteria was observed by field emission scanning electron microscope. Bacterial viability was determined by live/dead bacterial staining. Results: A uniform array of nanotubes could be seen on the surface of titanium samples in LL-37/NT group, and the top of the tube was covered with granular LL-37. Compared with PT group [the roughness was (2.30±0.18) nm, the contact angle was 71.8°±1.7°], the roughness [(20.40±3.10) and (19.10±4.11) nm] and hydrophilicity (the contact angles were 22.4°±3.1° and 25.3°±2.2°, respectively) of titanium samples increased in NT and LL-37/NT group (P<0.001). The results of in vitro release test showed that the release of antimicrobial peptide LL-37 was characterized by early sudden release (1-4 h) and long-term (1-7 d) slow release. With the immunofluorescence, more cell attachment was found on NT and LL-37/NT than that on PT at the first 0.5 and 2.0 h of culture (P<0.05). The results of CCK-8 showed that there was no significant difference in the proliferation of cells among groups at 1, 3 and 5 days after culture. Wound scratch assay showed that compared with PT and NT group, the cell moved fastest on the surface of titanium samples in LL-37/NT group at 24 h of culture [(96.4±4.9)%] (F=35.55, P<0.001). A monolayer cells could be formed and filled with the scratch in 24 h at LL-37/NT group. The results of bacterial test in vitro showed that compared with the PT group, the bacterial morphology in the NT and LL-37/NT groups was significantly wrinkled, and obvious bacterial rupture could be seen on the surface of titanium samples in LL-37/NT group. The results of bacteria staining showed that the green fluorescence intensity of titanium samples in LL-37/NT group was the lowest in all groups (F=66.54,P<0.001). Conclusions: LL-37/NT is beneficial to the adhesion and migration of HaCaT cells and has excellent antibacterial properties, this provides a new strategy for the optimal design of implant neck materials.

A Mechanistic Model of Aqueous Humor Flow to Study Effects of Angle Closure on Intraocular Pressure

Purpose

To study the relationship between the circumferential extent of angle closure and elevation in intraocular pressure (IOP) using a novel mechanistic model of aqueous humor (AH) flow.

Methods

AH flow through conventional and unconventional outflow pathways was modeled using the unified Stokes and Darcy equations, which were solved using the finite element method. The severity and circumferential extent of angle closure were modeled by lowering the permeability of the outflow pathways. The IOP predicted by the model was compared with biometric and IOP data from the Chinese American Eye Study, wherein the circumferential extent of angle closure was determined using anterior segment OCT measurements of angle opening distance.

Results

The mechanistic model predicted an initial linear rise in IOP with increasing extent of angle closure which became nonlinear when the extent of closure exceeded around one-half of the circumference. The nonlinear rise in IOP was associated with a nonlinear increase in AH outflow velocity in the open regions of the angle. These predictions were consistent with the nonlinear relationship between angle closure and IOP observed in the clinical data.

Conclusions

IOP increases rapidly when the circumferential extent of angle closure exceeds 180°. Residual AH outflow may explain why not all angle closure eyes develop elevated IOP when angle closure is extensive.

Translational Relevance

This study provides insight into the extent of angle closure that is clinically relevant and confers increased risk of elevated IOP. The proposed model can be utilized to study other mechanisms of impaired aqueous outflow.

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).

Detection of Nonglaucomatous Macula Findings With Ganglion Cell Analysis Printouts vs Full Macular Cube Scans

Importance

Ganglion cell analysis (GCA) of ocular coherence tomography (OCT) imaging is routinely used to detect and monitor glaucomatous damage of the ganglion cell complex in the macula. The GCA printout provides qualitative and quantitative data about the macular ganglion cell-inner plexiform layer and a single B-scan of the retina through the fovea. However, the full macular cube scan, including all 128 B-scans, is available for review. The macular cube scan provides considerable information about nonglaucomatous ocular pathology that may be missed if clinicians review only the GCA printout.

Objective

To determine the frequency and type of nonglaucomatous macular findings that are observable in the full macular cube scan but not the GCA printout.

Design, Setting, and Participants

A retrospective cross-sectional analysis of GCA printouts and full macular cube scans to detect nonglaucomatous macular pathology at a tertiary care academic center. Consecutive patients undergoing ganglion cell complex imaging during routine glaucoma evaluations over a 1-week period in a multi-clinician glaucoma clinic.

Main Outcomes and Measures

The prevalence and type of nonglaucomatous macular pathology visible on the GCA printout or macular cube scan.

Results

Among 105 patients (mean (SD) age, 67 (15.46) years; 63 [60%] female and 42 [40%] male) 201 eyes were imaged (64 [31.7%] with suspected glaucoma, 126 [62.4%] with open-angle glaucoma, 6 [3.0%] with closed-angle glaucoma, and 6 [3.0%] with other glaucoma). GCA printouts and macular cube scans revealed nonglaucomatous macular pathology in 65 eyes (32.2%). Of these, 25 eyes (38.5%) included findings that were not visible on the GCA printout. Of the cases not visible on the printout, 16 eyes (64.0% ) included macular pathology that required further evaluation.

Conclusions and Relevance

The findings indicate that nonglaucomatous macular pathology may be missed based on GCA printouts alone. While it may be beneficial to review the full macular cube to detect potentially vision-threatening disease and ensure proper patient care, this study cannot determine if this missed pathology affects clinical outcomes.

High-Frequency Ultrasound Elastography to Assess the Nonlinear Elastic Properties of the Cornea and Ciliary Body

Mechanical properties of the anterior anatomical structures of the eye, such as the cornea and ciliary body, play a key role in the ocular function and homeostasis. However, measuring the biomechanical properties of the anterior ocular structures, especially deeper structures, such as the ciliary body, remains a challenge due to the lack of high-resolution imaging tools. Herein, we implement a mechanical shaker-based high-frequency ultrasound elastography technique that can track the induced elastic wave propagation to assess the linear and nonlinear elastic properties of anterior ocular structures. The findings of this study advance our understanding of the role of anterior ocular structures in the pathogenesis of different ocular disorders, such as glaucoma.

Ocular Biometric Determinants of Dark-to-Light Change in Angle Width: The Chinese American Eye Study

PURPOSE

To assess ocular biometric determinants of dark-to-light change in anterior chamber angle width and identify dynamic risk factors in primary angle closure disease (PACD).

DESIGN

Population-based cross-sectional study.

METHODS

Chinese American Eye Study (CHES) participants underwent anterior segment optical coherence tomography imaging in the dark and light. Static dark and light biometric parameters, including angle opening distance, 750 µm (AOD750), anterior chamber width (ACW), lens vault (LV), and pupillary diameter (PD) were measured, and dynamic dark-to-light changes were calculated. Contributions by static and dynamic parameters to dark-to-light changes in AOD750 were assessed using multivariable linear regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squared (SPCC²). PACD was defined as ≥3 quadrants of gonioscopic angle closure.

RESULTS

The analysis included 1011 participants. All biometric parameters differed between dark and light (P < .05). On multivariable regression analysis, change in ACW (SRC = -0.35, SPCC² = 0.081) and PD (SRC = -0.46, SPCC² = 0.072) were the strongest determinants of dark-to-light change in AOD750 (overall R² = 0.40). Dark-to-light increase in AOD750 was less in eyes with than without PACD (0.081 mm and 0.111 mm, respectively; P < .001). ACW increased in eyes with PACD and decreased in eyes without PACD from dark to light (P < .025), whereas change in PD was similar (P = .28).

CONCLUSIONS

Beneficial angle widening effects of transitioning from dark to light are attenuated in eyes with PACD, which appears related to aberrant dark-to-light change in ACW. These findings highlight the importance of assessing the angle in both dark and light to identify potential dynamic mechanisms of angle closure.

Wedge Defects on Optical Coherence Tomography Angiography of the Peripapillary Retina in Glaucoma: Prevalence and Associated Clinical Factors

PRCIS

Among subjects with glaucoma, wedge-shaped defects on optical coherence tomography angiography (OCTA) were associated with disc hemorrhages (DH), paracentral visual field (VF) defects, increased cup-to-disc ratio (CDR), and thinner retinal nerve fiber layer (RNFL).

PURPOSE

To examine determinants of wedge defects on peripapillary OCTA in glaucoma.

MATERIALS AND METHODS

A total of 278 eyes of 186 subjects with mild to severe primary open-angle glaucoma underwent 6×6 spectral-domain OCTA imaging of the superficial peripapillary retina from 2016 to 2020 at an academic practice. Wedge defects were defined as focal microvasculature loss that extends outward from the optic nerve in an arcuate, wedge shape. Logistic regression models controlling for intereye correlation identified variables significantly associated with wedge defects. Eyes with profound microvasculature loss in both hemispheres were excluded. Candidate variables included: age, sex, race or ethnicity, diabetes, hypertension, follow-up duration, baseline untreated intraocular pressure, intraocular pressure at time of imaging, DH history, paracentral VF defects, CDR, central corneal thickness, spherical equivalent, VF mean deviation, RNFL thickness, and glaucoma stage.

RESULTS

Of 278 eyes, 126 (45.3%) had wedge defects in at least 1 hemisphere. In our multivariable logistic regression model, wedge defects were associated with DH history [odds ratio (OR): 3.19, 95% confidence interval (CI): 1.05-9.69, P=0.041], paracentral VF defects [OR: 4.38 (95% CI: 2.11-9.11), P<0.0001], larger CDR [OR: 1.27 (95% CI: 1.03-1.56), P=0.024, per 0.1 increase], and thinner RNFL [OR: 1.71 (95% CI: 1.25-2.34), P=0.0009, per 10 μm decrease].

CONCLUSION

DH history and paracentral VF defects were independently associated with wedge defects on OCTA, which was present in 45.3% of primary open-angle glaucoma patients. These findings may provide insight into glaucoma pathogenesis.

Angle closure extent, anterior segment dimensions and intraocular pressure

AIM

To investigate the association between the extent of iridotrabecular contact and other quantitative anterior segment dimensions measured by swept-source optical coherence tomography (SS-OCT; CASIA SS-1000, Tomey, Nagoya, Japan) with intraocular pressure (IOP).

METHODS

Cross-sectional study. All subjects who were ≥50 years with no history of glaucoma, ocular surgery or trauma, underwent SS-OCT imaging (eight equally spaced radial scans), Goldman applanation tonometry and gonioscopy on the same day. We measured iridotrabecular contact (ITC) index and area, total volume of trabeculo-iris space area and angle opening distance at 500 and 750 from the scleral spur (TISA 500 and 750, AOD 500 and 750, respectively), anterior chamber depth (ACD), volume, area and width, pupil diameter, lens vault and iris volume.Their relationship with IOP (dependent variable) was assessed by locally weighted scatterplot smoothing (Lowess) regression with change-point analysis and generalised additive models adjusted for confounders.

RESULTS

2027 right eyes of mostly Chinese Singaporeans (90%) were analysed. ITC index above a threshold of ~60% (95% CI 34% to 92%) was significantly associated with higher IOP. Independent of the extent of ITC, ACD was also significantly associated with higher IOP below a threshold of 2.5 mm (95% CI 2.33 mm to 2.71 mm). Greater ITC index and shallower ACD had a joint association with IOP. A model including ACD and ITC index was more predictive of IOP than a model considering these variables separately, particularly for women with gonioscopically closed angles (R² 52.7%, p<0.05).

CONCLUSIONS

The extent of angle closure and the ACD below a certain threshold had a significant joint association with IOP. These parameters, as biometrical surrogates of mechanical obstruction of the aqueous outflow, may jointly contribute to elevated IOP, particularly in women with gonioscopic angle closure.

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

PURPOSE

To assess baseline ocular biometric risk factors for progression from primary angle closure suspect (PACS) to primary angle closure (PAC) or acute angle closure (AAC).

DESIGN

Prospective, observational study.

PARTICIPANTS

Six hundred forty-three mainland Chinese with untreated PACS.

METHODS

Participants underwent baseline clinical examinations, including gonioscopy, anterior segment OCT (AS-OCT) imaging, and A-scan ultrasound biometry as part of the Zhongshan Angle Closure Prevention (ZAP) Trial. Primary angle closure suspect was defined as an inability to visualize pigmented trabecular meshwork in 2 or more quadrants based on static gonioscopy. Primary angle closure was defined as development of intraocular pressure above 24 mmHg or peripheral anterior synechiae. Progression was defined as development of PAC or an AAC attack. Multivariable logistic regression models were developed to assess biometric risk factors for progression.

MAIN OUTCOME MEASURES

Six-year progression from PACS to PAC or AAC.

RESULTS

Six hundred forty-three untreated eyes (609 nonprogressors, 34 progressors) of 643 participants were analyzed. In a multivariable model with continuous parameters, narrower horizontal angle opening distance of 500 μm from the scleral spur (AOD₅₀₀; odds ratio [OR], 1.10 per 0.01-mm decrease; P = 0.03), flatter horizontal iris curvature (IC; OR, 1.96 per 0.1-mm decrease; P = 0.01), and older age (OR, 1.11 per 1-year increase; P = 0.01) at baseline were associated significantly with progression (area under the receiver operating characteristic curve [AUC], 0.73). Smaller cumulative gonioscopy score was not associated with progression (OR, 1.03 per 1-modified Shaffer grade decrease; P = 0.85) when replacing horizontal AOD₅₀₀ in the multivariable model. In a separate multivariable model with categorical parameters, participants in the lowest quartile of horizontal AOD₅₀₀ (OR, 3.10; P = 0.002) and IC (OR, 2.48; P = 0.014) measurements and 59 years of age or older (OR, 2.68; P = 0.01) at baseline showed higher odds of progression (AUC, 0.72).

CONCLUSIONS

Ocular biometric measurements can help to risk-stratify patients with early angle closure for more severe disease. Anterior segment OCT measurements of biometric parameters describing the angle and iris are predictive of progression from PACS to PAC or AAC, whereas gonioscopy grades are not.

Optimal number and orientation of anterior segment OCT images to measure ocular biometric parameters in angle closure eyes: the Chinese American Eye Study

Purpose

To assess the optimal number and orientation of anterior segment optical coherence tomography (AS-OCT) images for accurately measuring ocular biometric parameters in angle closure eyes.

Methods

Subjects with angle closure, defined as >3 quadrants of non-visible pigmented trabecular meshwork on static gonioscopy, were selected from the Chinese American Eye Study. Mean angle opening distance (AOD500) was calculated using four images (0°−180°, 45°−225°, 90°−270° and 135°−315° meridians) from one eye per subject. Ten eyes from each quartile of AOD500 measurements were randomly selected for detailed 32-image analysis of 10 biometric parameters, including AOD500, iris curvature (IC), anterior chamber depth (ACD), lens vault (LV), and anterior chamber area (ACA). Mean and range of measurements from 1, 2, 4, 8 or 16 images were compared with 32-image values for all parameters.

Results

40 out of 335 eyes with angle closure were selected for 32-image analysis. Deviation from the 32-image mean was between 0.44% and 19.31% with one image, decreasing to 0.08% to 4.21% with two images for all parameters. Deviation from the 32-image range of measurements was between 54.67% to 88.94% with one image, decreasing to <7.00% with eight images for all parameters except ACD and ACA. Orienting the first image analysed along the 25°−205° meridian better approximated the range of measurements when four or fewer images were analysed.

Conclusions

Sectoral anatomical variations in angle closure eyes are easily misrepresented based on current AS-OCT imaging conventions. A revised multi-image approach can better capture the mean and range of biometric measurements.

Assessing accommodative presbyopic biometric changes of the entire anterior segment using single swept-source OCT image acquisitions

BACKGROUND/OBJECTIVES

To evaluate biometric changes throughout the anterior chamber during accommodation and presbyopia using single image acquisition swept-source anterior-segment optical coherence tomography (AS-OCT).

SUBJECT/METHODS

Anterior-segment images were obtained using a new swept-source AS-OCT device (ANTERION, Heidelberg Engineering) from healthy volunteers (n = 71) across two centers in this prospective observational case series. In one image acquisition, cornea through posterior lens, including the ciliary muscle on both sides of the right eye, was imaged. Subjects undertook no accommodative effort and -1, -3, and -5 D of target vergence. Two-way repeated measures ANOVA modeling was performed for ciliary muscle measurements, lens parameters, aqueous depth (AD), and pupil diameter (PD). The first ANOVA factor was accommodative stimuli, and the second factor included age and refractive status.

RESULTS

Maximum ciliary muscle thickness increased with accommodative stimuli (p < 0.001), while the distance from the scleral spur to the maximal point on the ciliary muscle and posterior ciliary muscle thickness (CMT2) decreased (p < 0.001-0.002). Older individuals showed no accommodative changes for ciliary muscle parameters, lens thickness, lens vault, PD, and AD (p = 0.07-0.32). Younger- and middle-aged eyes showed statistically significant accommodative structural alterations for these endpoints (p < 0.001-0.002), but with different patterns, including early loss of CMT2 contraction in middle-aged eyes. Within the middle-aged group, myopic eyes maintained better capacity for accommodative structural change.

CONCLUSIONS

Swept-source AS-OCT demonstrated multiple simultaneous anterior-segment biometric alterations in single acquisition images, including early loss of posterior ciliary muscle function and better maintained capacity for anterior-segment structural change in myopia.

Incidence of Proliferative Diabetic Retinopathy and Other Neovascular Sequelae at 5 Years Following Diagnosis of Type 2 Diabetes

OBJECTIVE

To determine the incidence and risk factors for developing proliferative diabetic retinopathy (PDR), tractional retinal detachment (TRD), and neovascular glaucoma (NVG) at 5 years after the initial diagnosis of type 2 diabetes.

RESEARCH DESIGN AND METHODS

Insured patients aged ≥18 years with newly diagnosed type 2 diabetes and 5 years of continuous enrollment were identified from a nationwide commercial claims database containing data from 2007 to 2015. The incidences of PDR, TRD, and NVG were computed at 5 years following the index diagnosis of type 2 diabetes. Associations between these outcomes and demographic, socioeconomic, and medical factors were tested with multivariable logistic regression.

RESULTS

At 5 years following the initial diagnosis of type 2 diabetes, 1.74% (1,249 of 71,817) of patients had developed PDR, 0.25% of patients had developed TRD, and 0.14% of patients had developed NVG. Insulin use (odds ratio [OR] 3.59, 95% CI 3.16-4.08), maximum HbA1c >9% or >75 mmol/mol (OR 2.10, 95% CI 1.54-2.69), renal disease (OR 2.68, 95% CI 2.09-3.42), peripheral circulatory disorders (OR 1.88, 95% CI 1.25-2.83), neurological disease (OR 1.62, 95% CI 1.24-2.11), and older age (age 65-74 years) at diagnosis (OR 1.62, 95% CI 1.28-2.03) were identified as risk factors for development of PDR at 5 years. Young age (age 18-23 years) at diagnosis (OR 0.46, 95% CI 0.29-0.74), Medicare insurance (OR 0.60, 95% CI 0.70-0.76), morbid obesity (OR 0.72, 95% CI 0.59-0.87), and smoking (OR 0.84, 95% CI 0.70-1.00) were identified as protective factors.

CONCLUSIONS

A subset of patients with type 2 diabetes develop PDR and other neovascular sequelae within the first 5 years following the diagnosis with type 2 diabetes. These patients may benefit from increased efforts for screening and early intervention.

Steps to Measurement Floor of an Optical Microangiography Device in Glaucoma

PURPOSE

To compare dynamic ranges and steps to measurement floors of peripapillary and macular metrics from a complex signal-based optical microangiography (OMAG^C) optical coherence tomography angiography (OCTA) device for glaucoma with those of OCT measurements.

DESIGN

Cross-sectional study.

METHODS

Imaging of 252 eyes from 173 patients with glaucoma and 123 eyes from 92 subjects without glaucoma from a glaucoma clinic was quantified using custom and commercial software. Metrics from OCT (retinal nerve fiber layer [RNFL], ganglion cell/inner plexiform layer [GCIPL]) and OCTA (custom: peripapillary vessel area density [pVAD], macular vessel area density [mVAD], and macular vessel skeleton density [mVSD]; commercial: peripapillary perfusion density [pPD^Z], macular perfusion density [mPD^Z], and macular vessel density [mVD^Z]) were plotted against visual field mean deviation (MD) with linear change-point analyses, measurement floors, and steps to floors.

RESULTS

Mean MD (dB) for glaucomatous eyes was -5.77 (-6.45 to -5.10). The number of eyes with mild glaucoma (MD >-6), moderate glaucoma (MD -6 to -12), and severe glaucoma (MD <-12) were 164, 50, and 38, respectively. pPD^Z yielded the lowest estimated floor at -26.6 dB (standard error [SE] 1.53), followed by OCTA macular metrics (-25 to -21 dB; SE 1.03) and pVAD (-17.6 dB, SE 1.06). RNFL and GCIPL produced floors at -17.8 (SE 0.927) and -23.6 dB (SE 1.14). The highest number of steps to measurement floor belonged to RNFL (7.20) and GCIPL (7.33), followed by pPD^Z (4.25), mVAD (3.87), and mVSD (3.81), with 2.5 or fewer steps for pVAD, mPD^Z, and mVD^Z.

CONCLUSIONS

pPD^Z, mVAD, and mVSD had approximately 4 steps within their dynamic ranges, without true measurement floors, and thus may be useful in evaluating advanced glaucomatous progression. Improving OCTA test-retest repeatability could augment number of steps for OCTA metrics, increasing their clinical utility.

Hemiretinal Asymmetry in Peripapillary Vessel Density in Healthy, Glaucoma Suspect, and Glaucoma Eyes

PURPOSE

To investigate hemiretinal asymmetry in radial peripapillary capillary vessel area density (VAD) of healthy, glaucoma suspect, and glaucoma eyes of varying severity and its diagnostic utility for glaucoma.

DESIGN

Population-based, cross-sectional study.

METHODS

Optic disc scans (6 × 6 mm) were collected on optical coherence tomography angiography (OCTA) to obtain VAD and on optical coherence tomography (OCT) to measure circumpapillary retinal nerve fiber layer (RNFL) thickness. Hemiretinal difference in VAD (hdVAD) was defined as the absolute difference between superior and inferior hemiretinal VAD. Age-adjusted multivariable linear regression of hdVAD on glaucoma severity was performed. Areas under curves (AUCs) were calculated from predicted probabilities generated by multiple logistic regression of glaucoma severity on age-adjusted single and combined parameters.

RESULTS

A total of 1,043 eyes of 1,043 participants (587 healthy, 270 suspect, 67 mild, 54 moderate, 65 severe glaucoma) were included. After age adjustment, mean hdVAD was similar between healthy and suspect (P = .225), higher in mild vs suspect (P < .001), and higher in moderate vs mild (P = .018), but lower in severe vs moderate (P = .001). AUCs of hdVAD were highest for discriminating mild (0.685) and moderate (0.681) glaucoma from healthy. Combining hdVAD and global RNFL (gRNFL) yielded the highest AUCs of all parameters for mild (0.818) and any POAG (0.859) and resulted in significantly better diagnostic accuracy than either hdVAD or gRNFL alone (P < .05 for all comparisons).

CONCLUSIONS

hdVAD is higher in early glaucoma and may help with early detection when damage is focal, but its diagnostic ability appears less robust in advanced glaucoma when damage is diffuse.

Impact of Visual Field Loss on Vision-Specific Quality of Life in African Americans: The African American Eye Disease Study

PURPOSE

To elucidate how visual field loss (VFL) impacts self-reported vision-specific quality of life (VSQOL) in African Americans, who experience a disproportionate burden of visual impairment.

DESIGN

Cross-sectional, population-based cohort.

METHODS

Eligible participants (n = 7,957) were recruited who self-identified as African American, were aged 40 years or older, and resided in Inglewood, California, USA. A total of 6,347 participants (80.0%) completed clinical eye examinations. Total mean deviation (MD) of VFL was measured bilaterally as decibels (dB) using the Humphrey SITA Standard 24-2 test. VSQOL was measured using the National Eye Institute Visual Function Questionnaire (NEI-VFQ 25) and scored using item response theory (IRT).

RESULTS

Participants with reliable data (n = 5,121) had a mean age of 60.7 years (standard deviation 11.0); those with worse VFL were older; had more comorbidities, lower income, less education, and worse visual acuity; and were more likely to be unemployed and depressed. Using IRT analysis, a change in VF of 6.2 (95% confidence interval [CI]: 5.3, 7.7) dB and 9.2 (95% CI: 7.5, 11.9) dB was necessary to observe a meaningful (5-point) difference in vision-related task and emotional well-being scores, respectively. VFL had the greatest impact on self-reported driving ability (6.0 dB [95% CI: 5.2, 7.1]), followed by satisfaction with general vision, near vision, vision-related mental health, and peripheral vision.

CONCLUSIONS

The strongest impact of VFL reported by African Americans was on their ability to complete visual tasks, especially for driving. An effect of VFL on emotional well-being also was observed, but the magnitude of association was about 50% lower for well-being compared to that of task.

Relationship Between Macular Vessel Density and Total Retinal Blood Flow in Primary Open-angle Glaucoma

PRECIS

An association between macular vessel density (VD) and total retinal blood flow (TRBF) was demonstrated in subjects with primary open-angle glaucoma (POAG) and visual field (VF) loss.

PURPOSE

The purpose of this study was to report relationships of macular VD metrics and TRBF in POAG.

MATERIALS AND METHODS

A total of 24 POAG and 19 healthy control subjects participated in the study. Subjects underwent optical coherence tomography and angiography for measurements of inner retinal thickness (IRT), VD, and spacing between large vessels (SLV) and small vessels (SSV). Doppler optical coherence tomography imaging was performed for TRBF measurement. In POAG subjects, automated perimetry was performed and VF loss expressed as mean deviation was measured.

RESULTS

Compared with the control group, POAG group had decreased VD, TRBF, IRT, and increased SLV (P<0.0001). Decreased VD (Pearson correlation, r=0.51; P<0.0001; N=43) and increased SLV (Spearman correlation, rs=-0.47; P=0.001) were correlated with decreased TRBF. Decreased VD and SSV (r≥0.39; P≤0.001; N=43) and increased SLV (rs=-0.71; P<0.0001) were associated with decreased IRT. Decreased VF mean deviation was correlated with decreased VD, SSV, IRT (r≥0.53; P≤0.001; N=24), and with increased SLV (rs=-0.84; P<0.0001).

CONCLUSIONS

The finding of an association between macular VD and TRBF supports the role of vascular factors in the pathophysiology of POAG and potential conduct of future studies aimed at identifying multiple image-based vascular metrics for disease diagnosis.

[Analysis of pathogen distribution and drug resistance of acute,delayed and chronic periprosthetic joint infection]

Objective: To analyze the pathogen distribution and drug resistance in acute,delayed and chronic periprosthetic joint infection (PJI). Methods: The clinical data of 316 patients with periprosthetic infection after primary hip and knee arthroplasty admitted to the Department of Arthroplasty,the First Affiliated Hospital,Xinjiang Medical University from August 2010 to August 2020 were retrospectively analyzed.There were 146 males and 170 females,aged (62.3±14.2) years (range:22 to 89 years).One hundred and sixty one patients underwent total hip arthroplasty and 155 patients underwent total knee arthroplasty.According to the time of postoperative infection,the patients were divided into acute PJI group (65 cases),delayed PJI group (83 cases) and chronic PJI group (168 cases).The results of pathogen species,composition ratio and drug susceptibility tests were collected,and the independent sample t test,Chi-square test or Fisher's exact probability test were used for comparison. Results: Gram-positive bacteria were the main pathogens of PJI (49.7%,157/316),and the positive rates of culture in patients with acute PJI,delayed PJI and chronic PJI were 33.8% (22/65),55.4% (46/83) and 53.0% (89/168),and the difference was statistically significant(χ²=8.343,P=0.015).The common bacteria were coagulase-negative Staphylococcus (54.8%,86/157) and Staphylococcus aureus (30.6%,48/157),The drug-sensitivity to linezolid,vancomycin and tigacycline was 100%.The gram-negative bacteria were mainly Escherichia coli and Enterobacter cloacae,and the drug resistance rate to carbapenems was low,ranging from 0 to 9.09%.The drug resistance rates of acute PJI patients to rifampicin,ciprofloxacin and erythromycin were significantly higher than those of late onset and chronic PJI patients,the difference was statistically significant(rifampicin:χ²=14.332,P=0.001;ciprofloxacin:χ²=12.086,P=0.002;erythromycin:χ²=9.096,P=0.010);The drug resistance rate of acute PJI patients to levofloxacin,clindamycin and tetracycline was higher than that of chronic PJI patients,and the difference was statistically significant(levofloxacin:χ²=10.500,P=0.002; clindamycin: χ²=7.103,P=0.007; tetracycline: χ²=6.909,P =0.012).The resistance rate of ampicillin/sulbactam in acute PJI (60.0%) was significantly higher than that in chronic PJI (16.7%),and the difference was statistically significant(χ²= 5.853,P=0.040). Conclusion: Gram-positive bacteria are the main pathogens of PJI,and the resistance rate of pathogens of acute PJI is higher than that of late onset and chronic PJI.

Glaucoma Expert-Level Detection of Angle Closure in Goniophotographs With Convolutional Neural Networks: The Chinese American Eye Study

PURPOSE

To compare the performance of a novel convolutional neural network (CNN) classifier and human graders in detecting angle closure in EyeCam (Clarity Medical Systems, Pleasanton, California, USA) goniophotographs.

DESIGN

Retrospective cross-sectional study.

METHODS

Subjects from the Chinese American Eye Study underwent EyeCam goniophotography in 4 angle quadrants. A CNN classifier based on the ResNet-50 architecture was trained to detect angle closure, defined as inability to visualize the pigmented trabecular meshwork, using reference labels by a single experienced glaucoma specialist. The performance of the CNN classifier was assessed using an independent test dataset and reference labels by the single glaucoma specialist or a panel of 3 glaucoma specialists. This performance was compared to that of 9 human graders with a range of clinical experience. Outcome measures included area under the receiver operating characteristic curve (AUC) metrics and Cohen kappa coefficients in the binary classification of open or closed angle.

RESULTS

The CNN classifier was developed using 29,706 open and 2,929 closed angle images. The independent test dataset was composed of 600 open and 400 closed angle images. The CNN classifier achieved excellent performance based on single-grader (AUC = 0.969) and consensus (AUC = 0.952) labels. The agreement between the CNN classifier and consensus labels (κ = 0.746) surpassed that of all non-reference human graders (κ = 0.578-0.702). Human grader agreement with consensus labels improved with clinical experience (P = 0.03).

CONCLUSION

A CNN classifier can effectively detect angle closure in goniophotographs with performance comparable to that of an experienced glaucoma specialist. This provides an automated method to support remote detection of patients at risk for primary angle closure glaucoma.

Anatomic Changes and Predictors of Angle Widening after Laser Peripheral Iridotomy: The Zhongshan Angle Closure Prevention Trial

PURPOSE

To assess anatomic changes after laser peripheral iridotomy (LPI) and predictors of angle widening based on anterior segment (AS) OCT and angle opening based on gonioscopy.

DESIGN

Prospective observational study.

PARTICIPANTS

Primary angle-closure suspects (PACSs) 50 to 70 years of age.

METHODS

Participants of the Zhongshan Angle Closure Prevention (ZAP) Trial underwent gonioscopy and AS-OCT imaging at baseline and 2 weeks after LPI. Primary angle-closure suspect was defined as the inability to visualize pigmented trabecular meshwork in 2 or more quadrants on static gonioscopy. Laser peripheral iridotomy was performed on 1 eye per patient in superior (between 11 and 1 o'clock) or temporal or nasal locations (at or below 10:30 or 1:30 o'clock). Biometric parameters in horizontal and vertical AS-OCT scans were measured and averaged. Linear and logistic regression modeling were performed to determine predictors of angle widening, defined as change in mean angle opening distance measured at 750 μm from the scleral spur (AOD₇₅₀); poor angle widening, defined as the lowest quintile of change in mean AOD₇₅₀; and poor angle opening, defined as residual PACS after LPI based on gonioscopy.

MAIN OUTCOME MEASURES

Anatomic changes and predictors of angle widening and opening after LPI.

RESULTS

Four hundred fifty-four patients were included in the analysis. Two hundred nineteen underwent superior LPI and 235 underwent temporal or nasal LPI. Significant changes were found among most biometric parameters (P < 0.006) after LPI, including greater AOD₇₅₀ (P < 0.001). One hundred twenty eyes (26.4%) showed residual PACS after LPI. In multivariate regression analysis, superior LPI location (P = 0.004), smaller AOD₇₅₀ (P < 0.001), and greater iris curvature (P < 0.001), were predictive of greater angle widening. Temporal or nasal LPI locations (odds ratio [OR], 2.60, P < 0.001) was predictive of poor angle widening. Smaller mean gonioscopy grade (OR, 0.34, 1-grade increment) was predictive of poor angle opening.

CONCLUSIONS

Superior LPI location results in significantly greater angle widening compared with temporal or nasal locations in a Chinese population with PACS. This supports consideration of superior LPI locations to optimize anatomic changes after LPI.

Ocular Biometric Determinants of Anterior Chamber Angle Width in Chinese Americans: The Chinese American Eye Study

PURPOSE

We sought to investigate anatomic mechanisms of angle narrowing by assessing ocular biometric determinants of anterior chamber angle width.

DESIGN

Population-based cross-sectional study.

METHODS

Subjects ≥50 years of age from the Chinese American Eye Study underwent a comprehensive ocular examination, including anterior segment optical coherence tomography imaging and ultrasound A-scan. Independent variables, including anterior chamber depth (ACD), lens vault (LV), iris curvature (IC), anterior chamber width, lens thickness, vitreous cavity depth, and axial length, and dependent variables, including angle opening distance, were measured in 1 randomly selected eye per subject. Univariable and multivariable regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squares (SPCC²) were used to assess relative and unique contributions by independent variables to angle width.

RESULTS

Two thousand two hundred twenty-five subjects (1433 women and 834 men) were included in the analysis. All biometric parameters except lens thickness differed between men and women (age-adjusted P < .001). In model 1A (R² = 0.66), which included ACD, lens thickness, and vitreous cavity depth, ACD (SRC = 0.64, SPCC² = 0.19) and IC (SRC = -0.26, SPCC² = 0.041) were the strongest determinants of angle opening distance. In model 1B (R² = 0.58), which included LV and axial length, LV (SRC = -0.46, SPCC² = 0.1) and IC (SRC = -0.3, SPCC² = 0.047) were the strongest determinants of angle opening distance. Determinants of angle width were similar in separate multivariable models for men and women.

CONCLUSIONS

ACD, LV, and IC are the strongest determinants of angle width in Chinese Americans. Sex-related differences in angle width are explained by differences among biometric measurements. These results provide insights into anatomic mechanisms of angle narrowing and have important implications for quantitative assessments of angle closure eyes.

A Randomized Controlled Trial Comparing Subconjunctival Injection to Direct Scleral Application of Mitomycin C in Trabeculectomy

PURPOSE

To compare the efficacy of intraoperative scleral application with subconjunctival injection of mitomycin C (MMC) in trabeculectomy.

DESIGN

Prospective, randomized, interventional study.

METHODS

This study took place in a single clinical practice in an academic setting. Patients had medically uncontrolled glaucoma as indicated by high intraocular pressure (IOP), worsening visual field, or optic nerve head changes in whom primary trabeculectomy was indicated. Patients were older than 18 years with medically uncontrolled glaucoma and no history of incisional glaucoma surgery. Patients were randomized to MMC delivered by preoperative subconjunctival injection or by intraoperative direct scleral application using surgical sponges during trabeculectomy. Comprehensive eye examinations were conducted at 1 day, 1 week, 6 weeks, 3 months, and 6 months postoperatively. Subconjunctival 5-fluorouracil injections were given postoperatively, as needed. The primary outcome was the proportion of patients who demonstrated IOP of <21 mm Hg and ≥30% reduction in IOP from baseline. Secondary outcome measures included the number of IOP-lowering medications, bleb morphology using the Indiana Bleb Appearance Grading Scale, and complication rates.

RESULTS

Participants (n = 100) were randomized into groups matched for baseline demographics, glaucoma status, and baseline IOP. At 6 months, there were no significant differences between the injection (n = 38) and sponge (n = 40) groups in surgical success (P = .357), mean IOP (P = .707), number of glaucoma medications (P = 1.000), bleb height (P = .625), bleb extension (P = .216), bleb vascularity (P = .672), or complications rates.

CONCLUSION

Both techniques of MMC delivery (subconjunctival injection and direct scleral application) resulted in comparable surgical outcomes and bleb morphologies.

Differences in Ocular Biometric Measurements among Subtypes of Primary Angle Closure Disease: The Chinese American Eye Study

PURPOSE

To assess differences in ocular biometric measurements between primary angle closure suspect (PACS) eyes and primary angle closure (PAC) and primary angle closure glaucoma (PACG) eyes.

DESIGN

Cross-sectional study.

PARTICIPANTS

Patients with primary angle closure disease (PACD) were identified from the Chinese American Eye Study, a population-based study in Los Angeles, California.

METHODS

Patients previously underwent complete ocular examinations including gonioscopy and anterior segment (AS)-OCT imaging with the Tomey CASIA SS-1000 (Tomey Corporation). Four AS-OCT images were analyzed per eye. Averaged and sectoral measurements of biometric parameters, including angle recess area (ARA), trabecular iris space area (TISA), iris area, iris curvature, lens vault, anterior chamber depth, and anterior chamber area, were compared between early PACD (PACS) and late PACD (PAC and PACG) groups. Machine learning classifiers that attempt to differentiate between early and late PACD eyes were developed by applying different regression algorithms to a training dataset of sectoral parameter measurements. Classifier performance was assessed using an independent test dataset.

MAIN OUTCOME MEASURES

Averaged and sectoral measurements of biometric parameters.

RESULTS

Two hundred ninety-eight eyes (231 PACS, 67 PAC or PACG) of 298 patients were analyzed. No difference was found in averaged biometric measurements between the 2 groups before (P > 0.09) or after (P > 0.14) adjusting for age and gender. Differences (P < 0.04) between the 2 groups were found for 11 sectoral parameter measurements, including ARA and TISA. The performance of machine learning classifiers developed using sectoral parameter measurements was poor on the independent test dataset for all regression algorithms (area under the receiver operating characteristic curve, 0.529-0.628).

CONCLUSIONS

Differences in biometric measurements between subtypes of PACD eyes were small in a population-based cohort of Chinese Americans. The poor performance of classifiers based on these measurements highlights potential challenges of developing quantitative methods to detect late PACD.

Intrasession repeatability and intersession reproducibility of peripapillary OCTA vessel parameters in non-glaucomatous and glaucomatous eyes

OBJECTIVE

To compare intrasession repeatability versus intersession reproducibility of the peripapillary vessel parameters using optical microangiography-based optical coherence tomography angiography (OCTA) in non-glaucomatous and glaucomatous eyes.

METHODS

In an observational, longitudinal study, peripapillary OCTA scans were collected to evaluate intrasession repeatability and intersession reproducibility using within-eye coefficient of variation (CV_W) and intraclass correlation coefficient (ICC). Images were quantified using a custom research-oriented quantification software calculating vessel area density (VAD) and flux and a commercially developed, clinic-oriented quantification software (Cirrus 11.0, Carl Zeiss Meditec) calculating perfusion density (PD) and flux index (FI). Effect of signal strength on the reliability of OCTA parameters was also evaluated.

RESULTS

Among 120 non-glaucomatous eyes, intrasession CV_W were 4.2% for VAD, 5.3% for flux, 1.5% for PD and 2.0% for FI. The intersession CV_W were 6.5% for VAD, 8.0% for flux, 2.0% for PD and 3.2% for FI. The intrasession ICC ranged from 0.928 to 0.945, and intersession ICC ranged from 0.811 to 0.866. From 118 glaucomatous eyes, intrasession CV_W was 9.0% for VAD, 10.3% for flux, 1.7% for PD and 2.3% for FI. The intersession CV_W was 12.1% for VAD, 14.2% for flux, 2.3% for PD and 3.5% for FI. The intrasession ICC ranged from 0.904 to 0.972, and intersession ICC ranged from 0.855 to 0.955. Signal strength was significantly positively associated with OCTA vessel parameters (p<0.0001) for both groups.

CONCLUSION

Peripapillary OCTA vessel parameters had greater intrasession repeatability compared to intersession reproducibility in both non-glaucomatous and glaucomatous eyes. The built-in commercially developed quantification software demonstrated greater agreement than the custom research-oriented quantification software.

Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices

Purpose

To assess the repeatability and agreement of ocular biometric parameters measured using the Tomey CASIA SS-1000 and Heidelberg ANTERION anterior segment optical coherence tomography (AS-OCT) devices.

Methods

Both eyes of subjects 18 years of age or older were scanned three times with the CASIA and ANTERION under standardized dark lighting. One AS-OCT image along the horizontal (temporal-nasal) meridian was analyzed per eye and per scan. Pupillary diameter (PD) was within 15% for all pairwise comparisons. Anterior chamber depth, lens vault, anterior chamber width, angle opening distance, trabecular iris space area, and scleral spur angle (SSA500) were measured using manufacturer-provided image analysis software. Intraclass correlation (ICC), Wilcoxon signed-rank, and Bland-Altman analyses were performed to assess intradevice repeatability and interdevice agreement of measurements.

Results

Thirty-two eyes of 21 subjects were analyzed. There was excellent agreement (ICC >0.98) and no significant difference (P > 0.05) in PD across all comparisons. Intradevice measurement repeatability was excellent for both the CASIA (ICC range 0.93–0.99) and ANTERION (ICC range 0.97–0.99). Interdevice measurement agreement was also excellent (ICC range 0.85–0.96). Measurements within and between devices were similar (P > 0.06) for all parameters except SSA500 (P = 0.03). Linear regression and Bland-Altman plots showed the relationship was consistent across the entire range of measurements.

Conclusions

Intradevice measurement repeatability is excellent for the CASIA and ANTERION. Interdevice measurement agreement between the two devices exceeds metrics reported by previous comparison studies.

Translational Relevance

Modern swept-source AS-OCT devices produce highly repeatable measurements of ocular biometric parameters that are nearly interchangeable across devices.

Rates of Eye Care and Diabetic Eye Disease among Insured Patients with Newly Diagnosed Type 2 Diabetes

PURPOSE

To determine rates of eye examinations and diabetic eye disease in the first 5 years after diagnosis of type 2 diabetes (DM2) among continuously insured adults.

DESIGN

Retrospective, longitudinal cohort study.

PARTICIPANTS

Insured patients aged 40 years or older with newly diagnosed DM2 (n = 42 684), and control patients without diabetes matched on age, sex, and race were identified from a nationwide commercial claims database containing data from 2007 to 2015.

METHODS

All patients were tracked for 6 years: 1 year before and 5 years after the index diabetes diagnosis. Receipt of eye care for individual patients was identified using International Classification of Diseases 9th edition (ICD-9) procedure codes or Current Procedural Terminology (CPT) codes indicating an eye examination, as well as encounters indicating the patient was seen by an ophthalmologist. A diagnosis of diabetic eye disease was determined by using ICD-9 codes.

MAIN OUTCOME MEASURES

Outcome measures included annual receipt of eye care and development of diabetic eye disease, namely, diabetic retinopathy (DR). Associations between these outcomes and demographic factors were tested with multivariable logistic regression.

RESULTS

Diabetic patients received more eye examinations than controls in each year, but no more than 40.4% of diabetic patients received an examination in any given year. Patients with Medicare Advantage received fewer eye examinations at 5 years (odds ratio [OR], 0.79; P < 0.01) than those with private insurance but were less likely to develop DR (OR, 0.71; P < 0.01). Hispanic patients had higher rates of DR (OR, 1.60; P < 0.01) and received fewer eye examinations (OR, 0.75; P < 0.01) at 5 years compared with White patients. Men received fewer eye examinations (OR, 0.84; P < 0.01) and were more likely to develop DR at 5 years (OR, 1.17; P < 0.01) than women. Patients with higher education were more likely to receive an eye examination and less likely to develop DR.

CONCLUSIONS

The majority of diabetic patients do not receive adequate eye care within the 5 years after initial diabetes diagnosis despite having insurance. Efforts should be made to improve adherence to screening guidelines, especially for vulnerable populations.

Effect of Angle Narrowing on Sectoral Variation of Anterior Chamber Angle Width: The Chinese American Eye Study

PURPOSE

To characterize the relationship between mean and sectoral variation of anterior chamber angle (ACA) width using anterior segment optical coherence tomography (AS-OCT).

METHODS

Subjects aged 50 years or older were identified from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. Each subject underwent a complete ocular examination including gonioscopy and AS-OCT imaging. Primary angle closure disease (PACD) was defined as inability to visualize pigmented trabecular meshwork in 3 or more quadrants. Four AS-OCT images from one eye per subject were analyzed and parameters describing ACA width were measured at 500 and 750 μm from the scleral spur: angle opening distance (AOD), trabecular iris space area (TISA), and scleral spur angle (SSA). The relationship between mean and sectoral variation of ACA width was assessed using locally-weighted scatterplot smoothing (LOWESS) regression and change-point analyses and Spearman correlation coefficients.

RESULTS

674 eyes (337 with PACD, 337 without PACD) from 674 subjects were analyzed. Overall, sectoral variation of ACA width decreased as mean ACA width decreased. This relationship was divided into two phases based on the change-point analysis. Sectoral variation of ACA width was strongly and significantly correlated (P < 0.001) with mean ACA width with below parameter-specific change points for most parameters: AOD500 (r = 0.599), AOD750 (r = 0.246), TISA500 (r = 0.734), TISA750 (r = 0.664), SSA500 (r = 0.661), SSA750 (r = 0.394). Correlations were weaker but still significant (P < 0.004) above these change points for most parameters: AOD500 (r = 0.321), AOD750 (r = 0.550), TISA500 (r = 0.122), TISA750 (r = 0.275), SSA500 (r = -0.036), SSA750 (r = 0.313). Correlations to the left and right of the change points strengthened when sectoral variation of ACA width was adjusted for mean ACA width.

CONCLUSIONS

Correlations between mean and sectoral variation of ACA width strengthen as the severity of angle narrowing worsens. This relationship likely reflects anatomical changes related to chronic angle closure and may be relevant for refining current definitions and management of PACD.

Deep Neural Network for Scleral Spur Detection in Anterior Segment OCT Images: The Chinese American Eye Study

Purpose

To develop a deep neural network that detects the scleral spur in anterior segment optical coherence tomography (AS-OCT) images.

Methods

Participants in the Chinese American Eye Study, a population-based study in Los Angeles, California, underwent complete ocular examinations, including AS-OCT imaging with the Tomey CASIA SS-1000. One human expert grader provided reference labels of scleral spur locations in all images. A convolutional neural network (CNN)-based on the ResNet-18 architecture was developed to detect the scleral spur in each image. Performance of the CNN model was assessed by calculating prediction errors, defined as the difference between the Cartesian coordinates of reference and CNN-predicted scleral spur locations. Prediction errors were compared with intragrader variability in detecting scleral spur locations by the reference grader.

Results

The CNN was developed using a training dataset of 17,704 images and tested using an independent dataset of 921 images. The mean absolute prediction errors of the CNN model were 49.27 ± 42.07 µm for X-coordinates and 47.73 ± 39.70 µm for Y-coordinates. The mean absolute intragrader variability was 52.31 ± 47.75 µm for X-coordinates and 45.88 ± 45.06 µm for Y-coordinates. Distributions of prediction errors for the CNN and intragrader variability for the reference grader were similar for X-coordinates (P = 0.609) and Y-coordinates (P = 0.378). The mean absolute prediction error of the CNN was 73.08 ± 52.06 µm and the mean absolute intragrader variability was 73.92 ± 60.72 µm.

Conclusions

A deep neural network can detect the scleral spur on AS-OCT images with performance similar to that of a human expert grader.

Translational Relevance

Deep learning methods that automate scleral spur detection can facilitate qualitative and quantitative assessments of AS-OCT images.

Vessel density and retinal nerve fibre layer thickness following acute primary angle closure

BACKGROUND

To evaluate changes in circumpapillary vessel density (cpVD) and retinal nerve fibre layer (cpRNFL) thickness after a successfully treated episode of acute primary angle closure (APAC) and to identify factors associated with glaucoma progression in these eyes.

METHODS

Twenty-six patients successfully treated for a unilateral episode of APAC were included in this prospective study. Optical coherence tomography (OCT) cpRNFL thickness and OCT angiography (OCTA) cpVD were compared between 2 and 8 months after treatment. Multiple logistic regression analysis was conducted to identify factors that influenced cpRNFL outcome.

RESULTS

cpRNFL thicknesses was thinner in the affected eye (94.0 µm (95% CI: 87.3 to 100.8)) than in the unaffected fellow eye (103.1 µm (99.3 to 106.9)) at 2 months (p=0.039). The cpRNFL thickness of the affected eye decreased 8 months after remission (89.5 µm (84 to 95)), but was unchanged in the unaffected eye. Although cpVD was significantly lower (p=0.001) in APAC eyes 2 months after treatment (56.7% (53.8 to 59.7)) compared with fellow eyes (62.9% (61.4 to 64.4)), there was no significant change in cpVD of the affected eye between 2 and 8 months. In the multivariable analysis, the only factor that was associated with cpRNFL progression was lower cpVD at 2 months after APAC remission (OR=1.79, p=0.036).

CONCLUSION

Early reductions of the vessel density and long-term decrease in cpRNFL thickness were observed during the first 8 months after an APAC attack. A lower vessel density at 2 months was the best predictor of conversion to an abnormal cpRNFL thickness. Glaucomatous progression should be suspected in eyes with lower vessel density even after remission of an episode of APAC.

Systemic Determinants of Peripapillary Vessel Density in Healthy African Americans: The African American Eye Disease Study

PURPOSE

To determine the relationship between systemic factors and radial peripapillary capillary (RPC) vessel density (VD) in healthy African American (AA) participants of the African American Eye Disease Study.

DESIGN

A population-based, cross-sectional study.

METHODS

A total of 4135 eyes from 2127 AA participants aged 40 years and older in Inglewood, California, were imaged for 6×6-mm optic disc scans on a spectral-domain optical coherence tomography angiography (OCTA) device. Of these, 1029 eyes from 1029 participants who met the inclusion and exclusion criteria were analyzed, including only 1 eye per participant. Custom software was used to quantify RPC VD. Multivariate linear regression was used to identify systemic factors associated with RPC VD with a significance level set at 0.05. The contribution of each variable to the final model was estimated with the magnitude of standardized regression coefficients (SRCs). The fit of the final model was measured by R².

RESULTS

The average RPC VD was 0.346±0.045. Controlling for signal strength, the systemic variables in the final multivariate model associated with reduced RPC VD were older age (β = -0.0123 per decade; SRC = -0.2733; P < .0001), male sex (β = -0.0067; SRC = -0.0716; P = .0060), and longer diabetes duration (β = -0.0022 per 5 years; SRC = -0.0527; P = .0427). The model R² was 0.3689.

CONCLUSIONS

Age, sex, and systemic influences, such as diabetes duration, need to be considered when assessing changes in RPC VD in glaucoma and other ocular diseases. Longitudinal studies are needed to investigate whether reduced RPC VD and the factors that affect it are associated with an increased risk of developing glaucomatous nerve damage.

Anterior Segment Optical Coherence Tomography: Applications for Clinical Care and Scientific Research

Anterior segment optical coherence tomography (AS-OCT) is a non-contact imaging technique that produces high-resolution images and quantitative measurements of the anterior segment and its anatomical structures. There has been rapid development of OCT technology over the past 2 decades, with the transition from time-domain to Fourier-domain OCT devices. By integrating these advancements in OCT technology, AS-OCT devices have evolved into versatile clinical and research tools for studies of the anterior segment and ocular surface. The primary purpose of this article was to review OCT technology and AS-OCT devices as well as applications of AS-OCT for clinical practice and scientific research. We first describe the different types of OCT technology, how they have been adapted for AS-OCT imaging, and differences between various AS-OCT devices. We then review the applications of AS-OCT for characterizing the anatomical structures of the anterior segment and aqueous outflow pathways, including the anterior chamber angle, trabecular meshwork, and Schlemm canal. We also describe glaucoma-related applications of AS-OCT imaging, which include evaluating patients for static and dynamic biometric risk factors of primary angle closure disease and assessing the efficacy of glaucoma interventions, such as laser peripheral iridotomy and glaucoma surgery. Finally, we review other clinical applications of AS-OCT imaging for detection and management of diseases of the ocular surface, cornea, and lens.

Differences in Anterior Chamber Angle Assessments Between Gonioscopy, EyeCam, and Anterior Segment OCT: The Chinese American Eye Study

Purpose

To quantify interquadrant differences in anterior chamber angle (ACA) configuration assessed on gonioscopy, EyeCam, and anterior segment optical coherence tomography (AS-OCT) in a cohort of Chinese Americans.

Methods

Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES), a population-based epidemiologic study in Los Angeles, CA. Each subject underwent a complete ocular exam, including gonioscopy, EyeCam, and AS-OCT, under dark ambient lighting. Gonioscopy and AS-OCT imaging and EyeCam image grading were performed by trained ophthalmologists.

Results

Seven hundred nine eyes from 709 subjects were analyzed. Less anatomic variation among the quadrants was detected on gonioscopy and EyeCam compared with AS-OCT (P < 0.05). The mean gonioscopy grade, EyeCam grade, and AS-OCT measurement for each quadrant varied by up to 10.3%, 6.4%, and 46.2% of the superior quadrant value, respectively. There were significant interquadrant differences (P < 0.05) among mean AOD750 measurements when grouping by quadrant and gonioscopy or EyeCam grade. Mean AOD750 measurements were smallest for the superior quadrant by between 14.3% and 38.1% and 17.4% and 37.9% on gonioscopy and EyeCam, respectively, compared with other quadrants.

Conclusions

Gonioscopy and EyeCam significantly underrepresent anatomic variations of the ACA compared with AS-OCT. Gonioscopy or EyeCam grades from different quadrants do not appear to be comparable or interchangeable, which supports reconsideration of current definitions and methods used to diagnose and manage primary angle closure disease.

Translational Relevance

AS-OCT imaging raises concerns about current clinical definitions and methods that rely gonioscopy or EyeCam to assess the ACA.

Quantitative Evaluation of Gonioscopic and EyeCam Assessments of Angle Dimensions Using Anterior Segment Optical Coherence Tomography

Purpose

To evaluate the relationship between angle dimensions assessed by gonioscopy or EyeCam and anterior segment optical coherence tomography (AS-OCT).

Methods

Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES). Each subject underwent a complete ocular exam, including gonioscopy, AS-OCT, and EyeCam. Angle closure was defined as three or more quadrants in which pigmented trabecular meshwork could not be visualized. Angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA) were measured in each AS-OCT image.

Results

709 eyes (272 angle closure, 437 open angle) from 709 subjects were analyzed. Mean gonioscopy and EyeCam grades tended to increase as AS-OCT measurements increased. There were strong correlations overall between AS-OCT measurements and gonioscopy (r > 0.73) and EyeCam (r > 0.68) grades. However, correlations with AS-OCT measurements were weak for gonioscopy (r < 0.38) and EyeCam (r < to 0.27) among eyes with angle closure. Mean AS-OCT measurements differed for eyes with Shaffer grade 0 in all four quadrants among eyes with varying degrees of angle closure on gonioscopy (P < 0.01) but did not differ among eyes with varying degrees of angle closure on EyeCam (P > 0.27).

Conclusions

Angle assessments by gonioscopy and EyeCam are weakly related to angle dimensions in eyes with angle closure.

Translational Relevance

AS-OCT imaging raises concerns about current clinical methods that rely on direct visualization of ACA structures to assess the degree of angle closure.

Azithromycin influences airway remodeling in asthma via the PI3K/Akt/MTOR/HIF-1α/VEGF pathway

Asthma is a respiratory disease that affects people of all walks of life, and is a hotspot of continuous research, with significant manpower and resources invested in its study. Airway remodeling is an important associated pathological change, and a mark of the irreversible damage produced by asthma. It involves compositional and functional changes in the cells of the airway walls, leading to reversible structural changes, and complicating treatment. Airway remodeling is mediated by different inflammatory pathways which have been targeted for treatment, with good results. However, given its complexity, systematic study of the pathogenesis of airway remodeling is still needed, and additional targeted therapies are necessary. Macrolide drugs, such as erythromycin, azithromycin, and clarithromycin, have antibacterial effects and also influence the cytokine secretion of macrophages and T-lymphocytes. They have direct effects on a variety of cytokines, inhibiting inflammation and reducing airway reactivity. In this study, we investigated the protective effect of azithromycin on airway remodeling through the phosphoinositol-3 kinase/Akt/mechanistic target of rapamycin kinase/hypoxia-inducible factor 1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathway. We observed that a long course of azithromycin could significantly reduce airway reactivity and ovalbulmin-induced pathological alterations in asthmatic mice. Gene expression analysis confirmed that HIF-1α and VEGF were significantly down-regulated following a long course of azithromycin administration.

Benefit of Measuring Anterior Segment Structures Using an Increased Number of Optical Coherence Tomography Images: The Chinese American Eye Study

Purpose

The purpose of this study was to evaluate the benefit of analyzing an increased number of anterior segment optical coherence tomography (AS-OCT) images on measurement values of various anterior segment parameters.

Methods

Subjects for this cross-sectional study were recruited from the Chinese American Eye Study (CHES), a population-based study in Los Angeles, CA. Thirty-two AS-OCT images were acquired from one eye each of 83 consecutive subjects. Sixteen parameters were analyzed in each image, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), scleral spur angle (SSAngle), lens vault (LV), pupillary diameter (PD), anterior chamber depth (ACD), anterior chamber width (ACW), iris area (IA), and anterior chamber area (ACA). Data from 1, 2, 4, 8, 16, or 32 OCT images were averaged across subjects to calculate the range and mean of measurement values for each parameter.

Results

Anatomical variations were poorly captured with fewer OCT images for AOD, ARA, TISA, SSAngle, IA, and LV. For these parameters, the range and mean of measurement values obtained from one OCT image deviated from 32-image values by up to 43.9% and 13.3% of the 32-image mean, respectively. These deviations decreased when additional OCT images were analyzed. Deviations from 32-image range and mean values were less pronounced regardless of image number for PD, ACD, ACW, and ACA, measuring up to 3.5% and 5.0%, respectively.

Conclusions

A multi-image approach should be the standard in OCT-based studies of AOD, ARA, TISA, TIA, SSAngle, IA, and LV.