Five year risk of progression of primary angle closure suspects to primary angle closure: a population based study

Progression of primary angle closure suspects: a systematic review and meta-analysis

This systematic review and meta-analysis examined the proportion of primary angle closure suspects (PACS) progressing to primary angle closure (PAC), acute angle closure (AAC), and primary angle closure glaucoma (PACG) and evaluated the impact of prophylactic laser peripheral iridotomy (LPI) on disease progression. A systematic search was performed on MEDLINE and EMBASE for studies published until November 2023 that reported on the proportion of PACS progressing to PAC. Using random-effects modelling, risk ratios and 95% confidence intervals estimated the proportion of progressing PACS between patients who received LPI versus those who did not. Two randomized-controlled-trials and three observational studies included a total of 1997 PACS patients. The weighted average age was 57.2 years with 74.7% females, and an average follow-up period of 6.2 years. Overall, 284 (14.2%) PACS patients progressed to either PAC (n = 258, 12.9%), AAC (n = 9, 0.5%), or PACG (n = 17, 0.9%). Patients receiving LPI displayed a 2.49-fold decrease in the risk of progression to PAC (RR: 2.49; 95% CI = 1.50-4.07; p < 0.001; NNT = 15), suggesting that there is a higher risk of disease progression without LPI. However, for the progressions to AAC and PACG, statistical significance was not reached. The present study provides valuable insights to the proportion of PACS who showed disease progression and underscores the potential benefit of prophylactic LPI in reducing the risk of angle closure disease progression. However, this study also addresses the issues surrounding the lack of demonstrated clinical efficacy for this intervention, thus advocating for a balanced approach in clinical decision-making.

Comparison of Swept-Source Anterior Segment Ocular Coherence Tomography and Gonioscopy in Detecting Anterior Chamber Angle Closure

Purpose

To compare the diagnostic accuracy of swept-source anterior segment optical coherence tomography (AS-OCT) with gonioscopy in detecting angle closure among narrow-angle suspected eyes.

Patients and Methods

A total of 125 eyes determined narrow anterior chamber angles suspected by Van Herick's technique grade 0, 1, or 2 were recruited. AS-OCT was undergone before any contact procedure. Intraocular pressure (IOP) measurements using applanation tonometry and gonioscopy were performed, respectively. AS-OCT images were blindly interpreted by 3 glaucoma specialists, involving both qualitative assessments at 0, 90, 180, and 270 degrees and quantitative analysis using iris-trabecular contact (ITC) index. The sensitivity and specificity of AS-OCT, compared with gonioscopy-the gold standard for identifying anterior chamber angle closure-were calculated.

Results

The mean age was 61±12.9 years, and females constituted 67.6%. Eyes classified by Van Herick's technique as grade 0, 1 and 2 were 16%, 58.40%, and 25.60%, respectively. Closed-angle identified by gonioscopy and AS-OCT were 100 eyes (80%) and 102 eyes (81.60%), respectively. The sensitivity and specificity of AS-OCT in detecting angle-closure were 92.16% (95% CI, 87.44-96.87) and 73.91% (66.22-81.61), respectively. For angle-closure identified by ITC index ≥ 55%, sensitivity was 86.36% (77.53-95.20) and specificity was 92.86 (86.23-99.49). The inter-observer agreement of gonioscopy was moderate (Kappa = 0.55), while the intra-observer and inter-observer agreement of AS-OCT was substantial (Kappa = 0.71-0.80 and Kappa = 0.69, respectively).

Conclusion

AS-OCT enables a contactless qualitative and quantitative assessment of angle-closure in narrow-angle suspected eyes, demonstrating high sensitivity, acceptable specificity, and good inter-observer and intra-observer reliability.

Assessing the clinical efficacy of phacoemulsification cataract extraction in treating acute primary angle closure and fellow primary angle closure suspect eyes using AS-OCT

Purpose

This study aimed to compare anterior segment parameters pre-and postoperatively in acute primary angle closure (APAC) and fellow primary angle closure suspect (PACS) eyes using anterior segment optical coherence tomography (AS-OCT) and evaluate the clinical effectiveness of cataract extraction in the treatment of APAC and fellow PACS eyes.

Methods

Quantitative measurements of various parameters, including anterior chamber depth (ACD), anterior chamber volume (ACV), lens vault (LV), iridocorneal angle contact index (ITCI), iris thickness (IT), iris volume (IV), and iris curvature (IC), were obtained using Tomey CASIA2 AS-OCT on 60 eyes from 30 patients (APAC eyes and their fellow PACS eyes) before and after surgery. Simultaneous analysis of the differences between the APAC eyes and fellow PACS eyes in these parameters, visual acuity (VA), and intraocular pressure (IOP) were performed.

Results

After surgery, both the APAC eyes and fellow PACS eyes (a total of 60 eyes) showed a significant increase in ACD and ACV, compared to preoperative measurements. Furthermore, LV and ITCI significantly decreased postoperatively. In the PACS group, IC significantly decreased postoperatively, while there was no statistically significant difference in the APAC group. In the APAC group, there was a significant decrease in IOP and improvement in VA at 1 day, 1 week, and the final follow-up compared to preoperative levels. The IOP values in the PACS group were within the normal range across various time points. VA in the PACS group showed significant improvement at 1 week postoperatively and at the final follow-up compared to preoperative levels. Significant differences of VA were observed in the initial, preoperative, first postoperative day, first postoperative week, and final follow-up, with better outcomes observed in the PACS group compared to the APAC group.

Conclusion

Lens extraction surgery can significantly improve anterior segment crowding in APAC and PACS eyes. For APAC eyes, combined cataract extraction with intraocular lens implantation and gonioscopy-assisted goniosynechialysis under direct visualization is feasible and safe. Further, in the fellow PACS eye of APAC patients with either significant or mild cataracts, phacoemulsification can maintain or improve preoperative visual acuity to varying degrees and stabilize IOP.

Artificial Intelligence in Anterior Chamber Evaluation: A Systematic Review and Meta-Analysis

PRCIS

In this meta-analysis of 6 studies and 5269 patients, deep learning algorithms applied to AS-OCT demonstrated excellent diagnostic performance for closed angle compared with gonioscopy, with a pooled sensitivity and specificity of 94% and 93.6%, respectively.

PURPOSE

This study aimed to review the literature and compare the accuracy of deep learning algorithms (DLA) applied to anterior segment optical coherence tomography images (AS-OCT) against gonioscopy in detecting angle closure in patients with glaucoma.

METHODS

We performed a systematic review and meta-analysis evaluating DLA in AS-OCT images for the diagnosis of angle closure compared with gonioscopic evaluation. PubMed, Scopus, Embase, Lilacs, Scielo, and Cochrane Central Register of Controlled Trials were searched. The bivariate model was used to calculate pooled sensitivity and specificity.

RESULTS

The initial search identified 214 studies, of which 6 were included for final analysis. The total study population included 5269 patients. The combined sensitivity of the DLA compared with gonioscopy was 94.0% (95% CI: 83.8%-97.9%), whereas the pooled specificity was 93.6% (95% CI: 85.7%-97.3%). Sensitivity analyses removing each individual study showed a pooled sensitivity in the range of 90.1%-95.1%. Similarly, specificity results ranged from 90.3% to 94.5% with the removal of each individual study and recalculation of pooled specificity.

CONCLUSION

DLA applied to AS-OCT has excellent sensitivity and specificity in the identification of angle closure. This technology may be a valuable resource in the screening of populations without access to experienced ophthalmologists who perform gonioscopy.

The Beijing angle closure progression study: design and methodology

Purpose

The purpose of this study is to summarize the design and methodology of a large-scale trial in northern China, the Beijing Angle Closure Progression Study (BAPS). This trial is designed to explore the 5-year incidence of primary angle-closure suspect (PACS) progressing to primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) and to determine the possible risk factors of disease progression.

Methods/design

The BAPS is a clinic-based, multicenter, noninterventional trial conducted on a sample of urban Chinese adults. Consecutive eligible patients who meet PACS diagnostic criteria will be recruited from eight participating centers, with the trial commencing on August 4, 2022. The target sample size is set at 825 subjects, with follow up planned for a minimum period of 5 years. Baseline examination will include presenting visual acuity, best corrected visual acuity, intraocular pressure (IOP), undilated slit-lamp biomicroscopy, stereoscopic evaluation of the optic disc, visual field test, optical coherence tomography evaluation of retinal nerve fiber layer, ultrasound biomicroscopy and IOLMaster. Questionnaires will also be used to collect detailed personal history. Patients are scheduled to visit the glaucoma clinic every 12 months and may visit the emergency room in case of acute attack of angle closure. Study endpoints include acute PAC episodes, elevated IOP, peripheral anterior synechiae, glaucomatous visual field defect, or glaucomatous abnormality of optic nerve.

Discussion

The BAPS will provide data on the 5-year incidence of PACS progressing to PAC or PACG and determine the risk factors for disease progression. This study will also help redefine high-risk patients with PACS.

Retinal vein occlusion in patients with primary angle closure: a prospective case-control study

OBJECTIVE

To compare the prevalence of angle closure in eyes with retinal vein occlusion (RVO) with control eyes and assess the possible association between angle-closure and RVO.

PATIENTS AND METHODS

This prospective, blinded case-control study included patients with a history of RVO (cases) and control individuals matched for age and refractive error. Clinical characteristics and angle-based structures derived from anterior-segment optical coherence tomography (AS-OCT) were analyzed.

RESULTS

Eighty-eight patients (44 per group) were included. The average age of the RVO and control groups was 59.8 ± 11.6 years and 60.8 ± 9.0 years, respectively (p = 0.667). There were no significant differences in terms of clinical characteristics between the 2 groups, including intraocular pressure (p = 0.837) and Shaffer gonioscopy grading (p = 0.620). None of the AS-OCT-derived angle characteristics were significantly different between the 2 groups. The number of angle-closure diagnoses between the RVO group (1 primary angle closure and 7 primary angle-closure suspects) and the control group (6 primary angle-closure suspects) did not differ significantly (p = 0.560). Anterior-chamber depth (ACD) was shallower in RVO eyes (2.72 ± 0.31 mm) than in the contralateral non-RVO eyes (2.76 ± 0.31 mm; p = 0.014).

CONCLUSIONS

This prospective, blinded, matched case-control study did not evidence any significant differences in clinical and AS-OCT-derived structural measures between RVO and control eyes. However, RVO eyes, compared with their contralateral non-RVO eyes, had a slightly shallower ACD. These findings collectively suggest that an association between primary angle-closure mechanisms and RVO is unlikely. However, the shallower ACD in RVO eyes could potentially put them at higher risk for intermittent or permanent pupillary block.

Long-term effects of mild cataract extraction versus laser peripheral iridotomy on anterior chamber morphology in primary angle-closure suspect eyes

AIM

To compare lens extraction (LE) and laser peripheral iridotomy (LPI) on anterior segment morphology in primary angle-closure suspect (PACS) eyes.

METHODS

This prospective clinical trial included 144 patients with PACS who underwent either LPI or LE. Ultrasound biomicroscopy (UBM) and gonioscopy were performed before and 1 month and 2 years after operation. Main outcomes included UBM parameters and the percentage of residual angle closure.

RESULTS

At both 1 month and 2 years of follow-up, LE showed a better effect of relieving anterior chamber crowding and widening the drainage angle, as obtaining a larger anterior chamber depth (ACD), angle opening distance, trabecular iris angle (TIA), trabecular iris space area, trabecular ciliary process distance (TCPD) and a smaller iris curvature (I-Curv) and lens vault (LV) (p<0.001). In the LPI group, angle width increased (angle opening distance at 500 µm from the scleral spur, TIA and trabecular iris space area at 500 µm from the scleral spur) and I-Curv decreased (p<0.001) at 1 month postoperatively, with no significant changes in ACD, LV or TCPD. However, at 2 years after LPI, the angle narrowed with the increase in LV over time, and the proportion of residual angle closure also increased from 21.7% to 30.4% (p<0.001). In contrast, after LE, the widened angle width, flattened iris, deepened ACD, decreased LV and increased TCPD all showed good sustainability in the comparison between 1-month and 2-year follow-up. No residual angle closure was observed either at 1 month or 2 years after LE.

CONCLUSIONS

LE was prior to LPI in widening the drainage angle. After LPI, there was a narrowing of the angle and an increase in the proportion of residual angle closure over time. LE could achieve a wider angle with no residual angle closure, and the anterior segment parameters were sustainable.

TRIAL REGISTRATION NUMBER

ChiCTR1800016511.

Characteristics of beta parapapillary atrophy in primary angle-closure suspect

OBJECTIVE

To investigate the characteristics of beta parapapillary atrophy (β-PPA) in patients with primary angle-closure suspect (PACS).

METHODS AND ANALYSIS

In total, 215 and 259 eyes with PACS and non-PACS (NPACS), respectively, were enrolled in this observational, cross-sectional study. Stereoscopic fundus and optical coherence tomography images were used to characterise β-PPA; the former was also used to measure the major β-PPA parameters. Univariate and multiple logistic regression analyses were used to identify the factors correlated with the presence of β-PPA and with β-PPA parameters.

RESULTS

The β-PPA occurrence rates were 48.80% and 44.40% in the PACS and NPACS groups, respectively, with no significant difference between groups. Compared with that in the NPACS group, the β-PPA area was significantly larger (p=0.005) in the PACS group, but the angular extent and maximum radial length did not differ between groups (p=0.110 and 0.657, respectively) after adjusting for age and axial length. The presence of β-PPA was associated with older age (OR 1.057, 95% CI 1.028 to 1.088, p<0.001) and larger disc area (OR 1.716, 95% CI 1.170 to 2.517, p=0.006). A larger β-PPA area was associated with older age (p=0.014), greater vertical cup-to-disc ratio (p=0.028), larger disc area (p<0.001) and PACS diagnosis (p=0.035).

CONCLUSION

48.80% of participants with PACS had β-PPA, which is slightly larger than NPACS. The area of β-PPA was larger in PACS, while the angular extent and maximum radial length did not differ between groups.

Cost-effectiveness analysis of prophylactic laser peripheral iridotomy for primary angle-closure suspect in Japan

BACKGROUND/OBJECTIVES

This study aimed to compare the cost-effectiveness of prophylactic laser peripheral iridotomy (LPI) with that of observation for primary angle-closure suspect (PACS) in Japan.

SUBJECTS/METHODS

A Markov model was developed to compare the costs and utilities of prophylactic LPI with those of observation of 40-year-old patients with PACS. In the model with a yearly cycle over a 20-year time horizon, the disease was postulated to irreversibly progress from PACS to primary angle closure, followed by primary angle-closure glaucoma, unilateral blindness, and bilateral blindness. The parameters were estimated mainly based on a recent randomised controlled trial and analyses of Japanese claims data. The incremental cost-effectiveness ratio was estimated from the healthcare payer's perspective and evaluated at the willingness-to-pay 5 million Japanese Yen per quality-adjusted life-year. The observation period and the age at entry into the cohort was changed to account for a variety of clinical courses in sensitivity analyses. We conducted one-way deterministic sensitivity analysis and probabilistic sensitivity analysis with Monte Carlo simulations with 10 000 iterations.

RESULTS

The incremental cost-effectiveness ratio of LPI was 2,287,662 Japanese Yen (14,298 pounds sterling) per quality-adjusted life-year, which was below the willingness-to-pay threshold. The ratios were approximately 4 and 8 million in the 15-year and 10-year time horizons, respectively. Increasing the age at entry had little influence on the incremental cost-effectiveness ratio. The deterministic and probabilistic sensitivity analyses indicated that the results were robust.

CONCLUSIONS

Our results indicate that prophylactic LPI for middle-aged patients with PACS is cost-effective in Japan.

Three-dimensional choroidal vascularity index and choroidal thickness in fellow eyes of acute and chronic primary angle-closure using swept-source optical coherence tomography

AIM

To compare the three-dimensional choroidal vascularity index (CVI) and choroidal thickness between fellow eyes of acute primary angle-closure (F-APAC) and chronic primary angle-closure glaucoma (F-CPACG) and the eyes of normal controls.

METHODS

This study included 37 patients with unilateral APAC, 37 with asymmetric CPACG without prior treatment, and 36 healthy participants. Using swept-source optical coherence tomography (SS-OCT), the macular and peripapillary choroidal thickness and three-dimensional CVI were measured and compared globally and sectorally. Pearson's correlation analysis and multivariate regression models were used to evaluate choroidal thickness or CVI with related factors.

RESULTS

The mean subfoveal CVIs were 0.35±0.10, 0.33±0.09, and 0.29±0.04, and the mean subfoveal choroidal thickness were 315.62±52.92, 306.22±59.29, and 262.69±45.55 µm in the F-APAC, F-CPACG, and normal groups, respectively. All macular sectors showed significantly higher CVIs and choroidal thickness in the F-APAC and F-CPACG eyes than in the normal eyes (P<0.05), while there were no significant differences between the F-APAC and F-CPACG eyes. In the peripapillary region, the mean overall CVIs were 0.21±0.08, 0.20±0.08, and 0.19±0.05, and the mean overall choroidal thickness were 180.45±54.18, 174.82±50.67, and 176.18±37.94 µm in the F-APAC, F-CPACG, and normal groups, respectively. There were no significant differences between any of the two groups in all peripapillary sectors. Younger age, shorter axial length, and the F-APAC or F-CPACG diagnosis were significantly associated with higher subfoveal CVI and thicker subfoveal choroidal thickness (P<0.05).

CONCLUSION

The fellow eyes of unilateral APAC or asymmetric CPACG have higher macular CVI and choroidal thickness than those of the normal controls. Neither CVI nor choroidal thickness can distinguish between eyes predisposed to APAC or CPACG. A thicker choroid with a higher vascular volume may play a role in the pathogenesis of primary angle-closure glaucoma.

Deep Learning Classification of Angle Closure based on Anterior Segment OCT

PURPOSE

To assess the performance and generalizability of a convolutional neural network (CNN) model for objective and high-throughput identification of primary angle-closure disease (PACD) as well as PACD stage differentiation on anterior segment swept-source OCT (AS-OCT).

DESIGN

Cross-sectional.

PARTICIPANTS

Patients from 3 different eye centers across China and Singapore were recruited for this study. Eight hundred forty-one eyes from the 2 Chinese centers were divided into 170 control eyes, 488 PACS, and 183 PAC + PACG eyes. An additional 300 eyes were recruited from Singapore National Eye Center as a testing data set, divided into 100 control eyes, 100 PACS, and 100 PAC + PACG eyes.

METHODS

Each participant underwent standardized ophthalmic examination and was classified by the presiding physician as either control, primary angle-closure suspect (PACS), primary angle closure (PAC), or primary angle-closure glaucoma (PACG). Deep Learning model was used to train 3 different CNN classifiers: classifier 1 aimed to separate control versus PACS versus PAC + PACG; classifier 2 aimed to separate control versus PACD; and classifier 3 aimed to separate PACS versus PAC + PACG. All classifiers were evaluated on independent validation sets from the same region, China and further tested using data from a different country, Singapore.

MAIN OUTCOME MEASURES

Area under receiver operator characteristic curve (AUC), precision, and recall.

RESULTS

Classifier 1 achieved an AUC of 0.96 on validation set from the same region, but dropped to an AUC of 0.84 on test set from a different country. Classifier 2 achieved the most generalizable performance with an AUC of 0.96 on validation set and AUC of 0.95 on test set. Classifier 3 showed the poorest performance, with an AUC of 0.83 and 0.64 on test and validation data sets, respectively.

CONCLUSIONS

Convolutional neural network classifiers can effectively distinguish PACD from controls on AS-OCT with good generalizability across different patient cohorts. However, their performance is moderate when trying to distinguish PACS versus PAC + PACG.

FINANCIAL DISCLOSURES

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE

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

DESIGN

Narrative review.

SUBJECTS

Patients classified as PACS.

METHODS

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

MAIN OUTCOME MEASURES

Incidence of progression to more severe forms of angle closure.

RESULTS

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

CONCLUSIONS

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

FINANCIAL DISCLOSURE(S)

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

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

PRCIS

Primary angle closure and primary angle closure glaucoma may exhibit normal intraocular pressure. Twenty-four-hour intraocular pressure fluctuation is highest in primary angle closure glaucoma. The degree of peripheral anterior synechiae was associated with a 24-hour intraocular pressure pattern in primary angle-closure disease without laser iridotomy.

PURPOSE

The purpose of this study was to study 24-hour intraocular pressure (IOP) patterns in eyes with chronic primary angle-closure disease and evaluate associations between peripheral anterior synechiae (PAS) and 24-hour IOP pattern.

PATIENTS AND METHODS

In this prospective cohort study, 59 eyes of 35 Asian patients with chronic primary angle-closure disease underwent complete ocular examinations at Ramathibodi Hospital, Mahidol University. Twenty-four-hour IOP records were obtained using Goldmann applanation tonometry at 2-hour intervals. Peak, mean, and trough 24-hour IOP values and 24-hour IOP fluctuation (difference between peak and trough values) were compared among groups. None of the participants received any treatment before complete data collection.

RESULTS

Even univariable analysis demonstrated a significant difference in peak, mean, and trough IOP and 24-hour IOP fluctuation between the 3 groups; the magnitude of trough IOP was not higher than 21 mmHg in all groups. In multivariable analysis, PAC and PACG eyes showed significantly higher peak IOP ( P =0.020 and 0.006, respectively) and 24-hour IOP fluctuation ( P =0.048 and 0.001, respectively) compared with PACS eyes. In comparison between combined PACS and PAC eyes versus PACG eyes, PACG eyes revealed significantly higher 24-hour IOP fluctuation. The degree of PAS was associated with peak and mean IOP values and with 24-hour IOP fluctuation in PAC and PACG eyes.

CONCLUSIONS

Twenty-four-hour IOP fluctuation was highest in PACG eyes. Although PAC and PACG eyes showed higher peak IOP and 24-hour IOP fluctuation values, compared with PACS eyes, trough IOP in PAC and PACG eyes were mostly below 21 mmHg. In addition, the degree of PAS was associated with a 24-hour IOP pattern in either PAC or PACG eyes.

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

Background

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

Aim

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

Methods

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

Results and data interpretation in the framework of 3P medicine

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

Supplementary Information

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

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

PURPOSE

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

DESIGN

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

PARTICIPANTS

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUIONS

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

FINANCIAL DISCLOSURE(S)

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

Cost-effectiveness of Prophylactic Laser Peripheral Iridotomy in Primary Angle-Closure Suspects

PURPOSE

To investigate the cost-effectiveness (CE) of prophylactic laser peripheral iridotomy (LPI) in primary angle-closure (PAC) suspects (PACSs).

DESIGN

Cost-effectiveness analysis utilizing Markov models.

SUBJECTS

Patients with narrow angles (PACSs).

METHODS

Progression from PACSs through 4 states (PAC, PAC glaucoma, blindness, and death) was simulated using Markov cycles. The cohort entered at 50 years and received either LPI or no treatment. Transition probabilities were calculated from published models, and risk reduction of LPI was calculated from the Zhongshan Angle Closure Prevention trial. We estimated costs of Medicare rates, and previously published utility values were used to calculate quality-adjusted life year (QALY). Incremental CE ratios (ICER) were evaluated at $50 000. Probabilistic sensitivity analyses (PSAs) addressed uncertainty.

MAIN OUTCOME MEASURES

Total cost, QALY, and ICER.

RESULTS

Over 2 years, the ICER for the LPI cohort was > $50 000. At 6 years, the LPI cohort was less expensive with more accrued QALY. In PSA, the LPI arm was cost-effective in 24.65% of iterations over 2 years and 92.69% over 6 years. The most sensitive parameters were probability of progressing to PAC and cost and number of annual office visits.

CONCLUSIONS

By 6 years, prophylactic LPI was cost-effective. The rate of progressing to PAC and differing practice patterns most impacted CE. With uncertainty of management of narrow angles, cost may be a decision management tool for providers.

FINANCIAL DISCLOSURE(S)

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

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

PURPOSE

To perform an in vivo evaluation of the changes in Schlemm's canal (SC) among patients with primary angle-closure disease (PACD) using swept-source optical coherence tomography (SS-OCT).

METHODS

Patients diagnosed with PACD who had not undergone surgery were recruited. The SS-OCT quadrants scanned herein included the nasal and temporal sections at 3 and 9 o'clock, respectively. The diameter and cross-sectional area of the SC were measured. A linear mixed-effects model was performed to analyze the effects of parameters on the SC changes. The hypothesis of interest was related to the angle status (iridotrabecular contact, ITC/open angle, OPN), which was further explored with pairwise comparisons of the estimated marginal means (EMMs) of the SC diameter and SC area. In the ITC regions, the relationship between the trabecular-iris contact length (TICL) percentage and SC parameters was also studied by a mixed model.

RESULTS

A total of 49 eyes of 35 patients were included for measurements and analysis. The percentage of observable SCs in the ITC regions was only 58.5% (24/41), whereas it was 86.0% (49/57) in the OPN regions (χ² = 9.44, p = 0.002). ITC was significantly associated with a decreasing SC size. The EMMs for the diameter and cross-sectional area of SC at the ITC and OPN regions were 203.34 μm versus 261.41 μm (p = 0.006) and 3174.43 μm² versus 5347.63 μm² (p = 0.022), respectively. Sex, age, spherical equivalent refraction, intraocular pressure, axial length, extent of angle closure, history of acute attack and treatment with LPI were not significantly associated with SC parameters. In the ITC regions, a larger TICL percentage was significantly associated with a decrease in SC diameter and area (p = 0.003 and 0.019, respectively).

CONCLUSIONS

The morphologies of SC could be affected by the angle status (ITC/OPN) in patients with PACD, and ITC was significantly associated with a decreasing SC size. These changes in SC as described by OCT scans might help to elucidate the progression mechanisms of PACD.

Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography

BACKGROUND

To evaluate anterior segment structural alterations after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT).

METHODS

This prospective study included 47 eyes in 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular-iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area, and ITC Index before ICL implantation surgery and at 1 month follow-up. The correlations among the ITC index, vault, and angle parameters were analysed. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault to identify eyes with suspected angle-closure.

RESULTS

At one month following ICL implantation, the ITC area was 0.396 ± 0.37 mm², and the ITC index is 8.143 ± 5.439%. All angle parameters, except ACW, showed a statistically significant reduction on SS-OCT (P < 0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500, and TIA750 values at one month postoperatively decreased by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8%, and 50.7%, respectively. The vault was positively correlated with the ITC index and percent change in anterior chamber angle parameters. A vault of > 0.659 mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%.

CONCLUSIONS

Anterior chamber angle parameters decreased one month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659 mm, it is necessary to be alert to possible closed angle suspicion.

Can ultrasonic biometric indices with optimal cut-offs be a potential screening tool for primary angle closure disease? A case-control study

BACKGROUND/OBJECTIVES

Despite a significant disease burden and potential to cause blindness, primary angle closure disease (PACD) does not have a population-based screening programme. Biometric indices using ultrasound A-scan is a potential tool for glaucoma case-detection. Given that genetic and environmental factors influence these parameters and paucity of data on their discrimination thresholds in Indian populace, we conducted a matched case-control study to determine the biometric indices and their discrimination thresholds associated with PACD.

METHODS

We studied 172 eyes of 86 participants (43 cases; 43 controls). We compared the following biometric parameters of cases (PACD, occludable angle ≥180° ± raised intraocular pressure) with age and gender-matched controls (1:1): Anterior chamber depth (ACD), lens thickness (LT), axial length (AXL), lens position (LP), relative lens position (RLP), lens axial factor (LAF), simple crowding value (Cs), ACD/AXL). We performed conditional logistic regression (to identify factors associated with PACD) and Receiver operating characteristic (ROC) analysis (to determine discrimination thresholds).

RESULTS

Reduced ACD (Adj OR 0.01; 95% CI: 0.0003-0.15, p < 0.001) and increased LT (Adj OR 10.3; 95% CI:2.42-43.93, p < 0.001) were associated with PACD. On ROC analysis, ACD, Cs, and ACD/AXL had optimum sensitivity/specificity at ≤3.015, ≥0.056 and ≤0.1303, respectively. ACD (88.4%) and Cs (94.2%) had highest sensitivity and specificity, respectively.

CONCLUSION

Ultrasonic biometric parameters differed significantly between PACD and controls. ACD and Cs (at discrimination thresholds of ≤3.015 mm and ≥ 0.056, respectively) using ultrasound A-scan could be a potential tool for PACD case-detection that requires evaluation of its diagnostic yield and cost-effectiveness.

Ten-year outcomes of cataract surgery for glaucoma management in patients with primary angle-closure disease

PURPOSE

To investigate the long-term outcomes of cataract surgery for glaucoma management in patients with primary angle-closure disease (PACD).

STUDY DESIGN

Retrospective case series.

METHODS

We reviewed the medical records of 87 eyes of 87 patients with PACD who underwent uncomplicated cataract surgery alone at the Kobe City Medical Center General Hospital. Only patients with a minimum follow-up of 10 years were included. The patients were divided into PACD spectrum categories: primary angle-closure glaucoma (PACG), primary-angle closure (PAC), and primary angle-closure suspect (PACS). The treatment outcomes were compared among the 3 groups. Intraocular pressure (IOP), number of glaucoma eye drops, requirement of additional glaucoma treatment, visual field progression, and progression to glaucoma during the follow-up period were evaluated.

RESULTS

Among the 87 patients, 39 had PACG; 26, PAC; and 22, PACS. Ten years after surgery, the IOP had significantly decreased from baseline in all 3 groups. The rate of requirement of additional glaucoma treatment during the follow-up period was significantly higher in the PACG group than in the other groups. Almost half of the patients with PACG required additional glaucoma treatment; of those patients, six (15.4%) underwent glaucoma surgery. Three patients (11.5%) with PAC required additional glaucoma medication. Visual field progression was observed in 28.1% of the patients with PACG. In 1 patient with PAC, the condition progressed to PACG, but there was no such progression in any of the patients with PACS.

CONCLUSIONS

We confirmed that cataract surgery had a long-term (> 10 years) effect on IOP reduction in eyes with PACD. Early intervention with cataract surgery may be preferable for glaucoma management in patients with PACD.

The Japan Glaucoma Society guidelines for glaucoma 5th edition

We are pleased to bring you the 5th edition of the Glaucoma Clinical Practice Guidelines. Clinical practice guidelines are based on evidence (scientific grounds). It is a document that presents the treatment that is the most appropriate for the patient. "Glaucoma Clinical Guidelines" was first published in 2003. This was the first guideline for glaucoma treatment in Japan. The principle of glaucoma treatment is to lower intraocular pressure. Means for lowering intraocular pressure includes drugs, lasers, and surgery; Glaucoma is a disease that should be considered as a complex syndrome rather than a single condition. Therefore, the actual medical treatment is not as simple as one word. This time we set the Clinical Questionnaire with a focus on glaucoma treatment. We hope that you will take advantage of the 5th edition.

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

PURPOSE

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

DESIGN

Retrospective case-control study.

PARTICIPANTS

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Inverse Relationship between Serum 25-Hydroxyvitamin D and Elevated Intraocular Pressure

Elevated intraocular pressure (EIOP) is the only major modifiable risk factor of glaucoma. While low serum vitamin D levels are considered a potential risk factor for glaucoma, there is conflicting evidence on the relationship between vitamin D and EIOP despite the possible linkage between vitamin D and intraocular pressure through oxidative stress and systemic inflammation. Therefore, the aim of this study is to verify the relationship between 25-hydroxyvitamin D [25(OH)D] and EIOP using data from 15,338 individuals who visited the health promotion center of an education hospital. The cubic spline curve revealed an inverse dose-dependent association between serum 25(OH)D level and EIOP. Using multiple logistic regression analysis, the fully adjusted odds ratio (OR) with 95% confidence interval (CI) for the EIOP of the serum 25(OH)D per increment was 0.97 (0.96-0.990). The fully adjusted ORs (95% CIs) for the EIOP of the 25(OH)D insufficiency and 25(OH)D sufficiency groups, compared to 25(OH)D deficiency group, were 0.72 (0.56-0.92) and 0.51 (0.34-0.78), respectively. The relationship remained significant in male and young age subgroups. In conclusion, the clinical assessment of intraocular pressure may prove helpful when treating patients with 25(OH)D deficiency, which may be a preventive strategy against the development of glaucoma.

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

PURPOSE

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

DESIGN

Multicenter, prospective study.

PARTICIPANTS

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

METHODS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

Anterior chamber parameters in cataract surgery candidates from middle China

To determine the distribution of the anterior chamber parameters and associated factors in cataractous adults from middle China. In this cross-sectional study, axial length, anterior chamber depth (ACD) and lens thickness (LT) were measured with IOLMaster 700. The Pentacam HR was designed to measure the anterior chamber volume (ACV) and anterior chamber angle (ACA). Patients' data were collected and analyzed between 2020 and 2022. A total of 157 eyes of 157 Chinese adults (mean age: 64.43 ± 12.16 years) with a cataract were enrolled in this study. The mean values measured were as follows: axial length, 24.10 ± 2.44mm; ACD, 2.99 ± 0.52 mm; LT, 4.51 ± 0.48 mm; ACV, 113.98 ± 45.12 mm3; ACA, 32.33 ± 7.66 degrees. The ACD and ACV were statistically significantly greater in men than in women and had a decrease trend as age and LT increased. In the simulated linear equation of age with ACD and LT the absolute slope coefficients of equations were the same; however, the directions were opposite. The mean ACV was <100 mm3 when the patients were over 60 years. In the multivariate regression analysis of ACD, ACV and ACA there was a reasonable prediction with adjusted R2 = 0.878, 0.847 and 0.564, respectively. This study may provide normative data for cataract patients. The profile of anterior chamber can help improve the knowledge of the risk of angle closure in cataract candidates.

Increase in anterior chamber angle depth after topical pilocarpine measured by spectral domain optical coherence tomography: A possible additional indicator for laser peripheral iridotomy in primary angle-closure suspects in an opportunistic set-up

Purpose

Indication of laser peripheral iridotomy (LPI) is often conjectural due to dependency on gonioscopy and strict dichotomous classification of occludability. Indentation gonioscopy is the gold standard but is under-utilized for various reasons. The prevalence of primary angle closure disease (PACD) in eastern India is 1.5-1.9%, with a 22% five-year progression rate. Many angle closure patients may go blind without timely diagnosis and iridotomy. General ophthalmologists need alternate, validated methods for diagnoses. Pilocarpine eye drop causes miosis, and flattens the iris, producing angle changes detectable by spectral domain optical coherence tomography (SD-OCT). We hypothesized that the amount of angle change may be a suitable indicator for iridotomy.

Methods

Our prospective cross-sectional single-masked observational study evaluated pilocarpine-induced changes in angle parameters detected by SD-OCT. Out of 372 patients enrolled, 273 patients (539 eyes) remained, with a mean age of 48.6 years (SD = 10.36). All eyes were graded by the Van Herick (VH) method, gonioscopy, and anterior segment (AS) SD-OCT and reassessed after pilocarpine drops.

Results

The sensitivity and specificity of tomography measurements against gonioscopy grades were 61% and 85%, respectively. The receiver operating characteristic (ROC) curve was 0.85. Pilocarpine-induced angle widening was significant in gonioscopically narrower angles. Low Van Herick grades (217 eyes), narrow gonioscopy grades (238 eyes), and a narrow OCT angle value (165 eyes) were candidates for iridotomy.

Conclusion

Our study results showed that pilocarpine-induced angle widening detected by SD-OCT could be a strong objective indicator for LPI.

Corvis Biomechanical Factor Facilitates the Detection of Primary Angle Closure Glaucoma

Purpose

To characterize the corneal biomechanical properties of primary angle closure glaucoma (PACG) and to investigate the diagnostic performance of combining corneal biomechanical parameters and anterior segment parameters in detecting PACG.

Methods

This retrospective cross-sectional study evaluated 79 and 81 eyes of normal controls and patients with PACG, respectively. Corvis Biomechanical Factor (CBiF) and anterior chamber volume (ACV) were measured using the Corvis ST and Pentacam, respectively. We performed multivariable logistic regression, adjusted for age, sex, central corneal thickness, intraocular pressure, and ACV to evaluate the effect of CBiF on PACG. The area under the receiver operating curve (AUC) was calculated to compare the diagnostic performance of ACV, CBiF, and ACV-CBiF combination for detecting PACG.

Results

The median CBiF of the control and PACG groups was 6.61 (interquartile range [IQR], 6.39–6.88) and 6.20 (IQR, 5.93–6.48), respectively (P < 0.001). A lower CBiF, suggestive of decreased corneal biomechanical stability, increased the odds of PACG (odds ratio, 0.029; 95% confidence interval [CI], 0.003–0.266; P = 0.002) in the multivariable logistic regression model. The ACV–CBiF combination yielded the highest AUC (0.934; 95% CI, 0.882–0.968) compared with ACV alone (0.878; 95% CI, 0.823–0.928). The ACV-CBiF combination had significantly higher discriminatory ability than that of ACV alone (DeLong test, P = 0.004).

Conclusions

Lower CBiF and ACV may act as independent predictors for PACG. Combining ACV and CBiF may enhance detection of PACG.

Translational Relevance

The combination of corneal biomechanical parameters and anterior segment parameters enhances the detection of PACG.

Clinical implication of recent randomized control trial in primary angle-closure disease management

Blindness due to primary angle-closure glaucoma (PACG) can be reduced significantly if the ongoing angle-closure process is arrested at an early stage. Various treatments such as laser peripheral iridotomy (LPI), iridoplasty, and clear lens extraction (CLE) have been advocated as first-line therapy for primary angle-closure (PAC), PACG, and high-risk cases of primary angle-closure suspect (PACS). EAGLE study, propagated the effectiveness of CLE over LPI for the management of primary angle closure and have sparked controversy regarding the role of LPI as a first line procedure. Randomized controlled trials (RCT), systematic reviews, and meta-analyses of RCTs done on the same question provide us with a solid base for creating guidelines/modules for our day-to-day clinical practice. A systematic review was conducted, searching several databases, including PubMed, Cochrane Library, EMBASE, and ClinicalTrials.gov, for the last 16 years (January 2005–December 2021) for RCTs with data published related to primary angle-closure disease (PACD). The search strategy included the following terms: “Primary Angle Closure disease,” “Primary Angle Closure Glaucoma,” “Primary Angle Closure,” “Primary Angle Closure Suspect,” “clear lens extraction,” “laser iridotomy,” “laser peripheral iridotomy,” “argon laser peripheral iridoplasty,” “selective laser trabeculoplasty,” “trabeculectomy,” “randomized control trial,” and “meta-analysis of randomized control trial.” In this review, we will discuss recently published RCTs (within the last 16 years) for the management of PACD and their clinical implications in day-to-day practice.

In vivo biomechanical assessment of iridial deformations and muscle contractions in human eyes

The iris is a muscular organ whose deformations can cause primary angle-closure glaucoma (PACG), a leading cause of blindness. PACG risk assessment does not consider iridial biomechanical factors, despite their expected influence on iris deformations. Here, we exploited an existing biometric dataset consisting of near-infrared movies acquired during the pupillary light reflex (PLR) as a unique resource to study iris biomechanics. The PLR caused significant (greater than 100%) and essentially spatially uniform radial strains in the iris in vivo, consistent with previous findings. Inverse finite-element modelling showed that sphincter muscle tractions were ca fivefold greater than iridial stroma stiffness (range 4- to 13-fold, depending on sphincter muscle size). This muscle traction is greater than has been previously estimated, which may be due to methodological differences and/or to different patient populations in our study (European descent) versus previous studies (Asian); the latter possibility is of particular interest due to differential incidence rates of PACG in these populations. Our methodology is fast and inexpensive and may be a useful tool in understanding biomechanical factors contributing to PACG.

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.

Hybrid Variation-Aware Network for Angle-Closure Assessment in AS-OCT

Automatic angle-closure assessment in Anterior Segment OCT (AS-OCT) images is an important task for the screening and diagnosis of glaucoma, and the most recent computer-aided models focus on a binary classification of anterior chamber angles (ACA) in AS-OCT, i.e., open-angle and angle-closure. In order to assist clinicians who seek better to understand the development of the spectrum of glaucoma types, a more discriminating three-class classification scheme was suggested, i.e., the classification of ACA was expended to include open-, appositional- and synechial angles. However, appositional and synechial angles display similar appearances in an AS-OCT image, which makes classification models struggle to differentiate angle-closure subtypes based on static AS-OCT images. In order to tackle this issue, we propose a 2D-3D Hybrid Variation-aware Network (HV-Net) for open-appositional-synechial ACA classification from AS-OCT imagery. Specifically, taking into account clinical priors, we first reconstruct the 3D iris surface from an AS-OCT sequence, and obtain the geometrical characteristics necessary to provide global shape information. 2D AS-OCT slices and 3D iris representations are then fed into our HV-Net to extract cross-sectional appearance features and iris morphological features, respectively. To achieve similar results to those of dynamic gonioscopy examination, which is the current gold standard for diagnostic angle assessment, the paired AS-OCT images acquired in dark and light illumination conditions are used to obtain an accurate characterization of configurational changes in ACAs and iris shapes, using a Variation-aware Block. In addition, an annealing loss function was introduced to optimize our model, so as to encourage the sub-networks to map the inputs into the more conducive spaces to extract dark-to-light variation representations, while retaining the discriminative power of the learned features. The proposed model is evaluated across 1584 paired AS-OCT samples, and it has demonstrated its superiority in classifying open-, appositional- and synechial angles.

Development of angle closure and associated risk factors: The Handan eye study

PURPOSE

To investigate the development of angle closure from baseline open angle and associated risk factors in a rural Chinese population through a longitudinal study over a 5-year period.

METHODS

Subjects aged ≥30 years and older with bilateral open angles at baseline of the Handan Eye Study who participated in the follow-up and had undergone both baseline and follow-up gonioscopic examinations were included. Subjects with any form of angle closure, glaucoma, incisional ocular surgery or other conditions that could influence the results were excluded. The development of angle closure was defined as the presence of primary angle closure suspect (PACS) or primary angle closure (PAC)/primary angle closure glaucoma (PACG) during the follow-up in normal subjects with baseline bilateral open angles. Logistic regression was performed to identify the baseline risk factors for the development of angle closure.

RESULTS

A total of 457 subjects with bilateral open angles at baseline aged 53.0 (45.5, 58.0) years were enrolled. 94.7% of the included cases developed PACS, 5.3% developed PAC and no one developed PACG after 5 years. In logistic regression, significant risk factors for the development of angle closure were shallower central anterior chamber depth (ACD) (p = 0.002) and narrower mean angle width (p < 0.001).

CONCLUSIONS

This study reports the development from baseline open angle to angle closure after a 5-year follow-up. We confirm that the mean angle width and central ACD were independent predictive risk factors for the development of any form of angle closure.

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

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

[Primary anterior chamber angle closure: progression from suspect to glaucoma. Part 1. Frequency and rate of transition from suspected primary angle closure to true angle closure and primary angle closure glaucoma]

To review the literature devoted to the problem of primary anterior chamber angle closure (PAC) and the development of this pathology from glaucoma suspect to primary angle closure glaucoma. The paper includes a trend analysis of the studies concerning primary angle closure suspects (PACS). The concept of this review is conditioned by the conflicting strategies for treating patients with initial PAC without glaucomatous optic neuropathy. Solving the problem of angle closure plays a key role in preventing the development of PAC glaucoma, which is the world's leading cause of irreversible blindness. This part of the review provides information on the frequency and rate of disease progression in PACS. The analyzed literature data is contradictory and indicates the need for further search that would consider a standardized approach to defining the concept of PAC disease, demographic factors and unified examination methods for generalizing and systematizing data in order to draw out unified treatment recommendations.

Evaluation of the Diagnostic Performance of Swept-Source Anterior Segment Optical Coherence Tomography in Primary Angle Closure Disease

PURPOSE

To evaluate the diagnostic performance of swept-source anterior segment optical coherence tomography (SS-OCT) in differentiating eyes with primary angle closure disease (PACD) from eyes of control subjects, as well as eyes with PAC and PAC glaucoma (PACG) from eyes with PAC suspect (PACS) disease.

DESIGN

Multicenter cross-sectional study.

METHODS

Chinese patients were classified into control, PACS, and PAC/PACG groups. The area under the receiving operating characteristic curve (AUC) from logistic regression models was used to evaluate discriminating ability. Sensitivity and specificity were calculated, and performance of the models was validated using an independent dataset.

RESULTS

A total of 2928 SS-OCT images from 366 eyes of 260 patients were recruited to develop diagnostic models. The validation dataset included 1176 SS-OCT images from 147 eyes of 143 patients. For distinguishing PACD from control eyes, average anterior chamber depth had the highest AUC (0.94). With a cutoff of 2.2 mm for average anterior chamber depth, the sensitivity and specificity were 90.2% and 85.2% in the training set. For distinguishing PAC/PACG from PACS, a multivariate model had an AUC of 0.83, with sensitivity and specificity of 82.0% and 62.8% in the training set. The validation set confirmed the findings.

CONCLUSIONS

SS-OCT of the anterior segment showed excellent diagnostic performance distinguishing PACD from normal eyes and moderate diagnostic ability distinguishing eyes with PAC/PACG from eyes with PACS. ACD alone may provide a simple and effective way to diagnose PACD from control subjects. As ACD can be obtained using other more available modalities, this has implications for the early diagnosis of PACD.

Prevalence and risk factors for primary angle-closure disease spectrum: The Colombian glaucoma study

PURPOSE

To estimate the prevalence and risk factors associated with the primary angle-closure disease spectrum in participants of the Colombian Glaucoma Study.

METHODS

A cross-sectional study in subjects older than 50 years with a diagnosis of diabetes mellitus or/and systemic hypertension was conducted in Colombia to estimate glaucoma prevalence. This study included 1749 patients and classified them using gonioscopy into either open-angle or primary angle-closure disease spectrum groups. The patients in the primary angle-closure disease spectrum group were then subdivided into the following categories: primary angle-closure suspect, primary angle-closure, and primary angle-closure glaucoma. A logistic regression model was carried out to identify factors related to the primary angle-closure disease spectrum, including age, sex, height, and refraction.

RESULTS

The prevalence of primary angle-closure disease spectrum was 19.3% (338) (95% CI: 17.5-21.2). The prevalence of primary angle-closure suspect, primary angle-closure, and primary angle-closure glaucoma was 8.0% (140) (95% CI: 6.8-9.4), 10.1% (176) (95% CI: 8.7-11.6), and 1.2% (22) (95% CI: 0.8-1.9), respectively. In the multivariate analysis, advanced age (+80 years), female sex, and high hyperopia (p = 0.000, 0.021, and 0.001, respectively) were identified as independent factors related to the primary angle-closure disease spectrum.

CONCLUSION

A high prevalence of primary angle-closure disease spectrum was found in Colombian patients with a diagnosis of diabetes mellitus or/and systemic hypertension, especially primary angle-closure and primary angle-closure glaucoma. Age, female sex, and high hyperopia were identified as risk factors for the primary angle-closure disease spectrum.

Association of peripheral anterior synechia, intraocular pressure, and glaucomatous optic neuropathy in primary angle-closure diseases

AIM

To investigate the association of peripheral anterior synechiae (PAS) with intraocular pressure (IOP) and glaucomatous optic neuropathy (GON) in primary angle closure (PAC) and primary angle-closure glaucoma (PACG).

METHODS

Totally 355 eyes (238 PAC and 117 PACG) of 181 patients were included in this retrospective analysis of baseline data from a randomized clinical trial. All patients had undergone a comprehensive ophthalmic examination. The extent of PAS in clock hours as determined on gonioscopy was documented. The independent effect of the extent of PAS on IOP and the prevalence of GON were determined using multivariable generalized estimating equation (GEE) models.

RESULTS

The frequency of GON increased with the extent of PAS and a higher IOP. PAS were more extensive (8 vs 1 clock hour, P<0.001) and IOP higher (28.01 vs 18.00 mm Hg, P<0.001) in PACG compared to PAC. The prevalence of GON among the PAS quartiles were 10.2% (PAS<0.5 clock hours), 16.9% (PAS≥0.5 and PAS<3 clock hours), 29.6% (PAS≥3 and PAS<7 clock hours), and 74.4% (PAS≥7 clock hours), respectively. After adjusting for IOP, age, gender, spherical equivalent, average Shaffer score and number of medications, the odds ratio (OR) for GON was 4.4 (95%CI: 1.5-13.0; P=0.007) with PAS≥3 clock hours and 13.8 (95%CI: 4.3-43.6; P<0.001) with PAS≥7 clock hours as compared to eyes with PAS<0.5 clock hours. The frequency of GON increased linearly with the extent of PAS. Extent of PAS was also associated with higher IOP. Eyes with both PAS≥6 clock hours and IOP≥21 mm Hg had the highest risk of GON compared to eyes with both PAS<6 clock hours and IOP<21 mm Hg (OR=18.0, 95%CI: 7.5-43.4; P<0.001).

CONCLUSION

The extent of PAS in PAC and PACG is an important predictor of higher IOP and is linearly associated with GON independent of IOP, suggesting other factors related to PAS formation may be involved in the development of GON in PACG.

Fifteen-Year Incidence Rate of Primary Angle Closure Disease in the Andhra Pradesh Eye Disease Study

PURPOSE

To report on the 15-year incidence of primary angle closure disease (PACD) among participants aged ≥40 years in rural southern India DESIGN: Population-based longitudinal incidence rate study METHODS: Setting: 3 rural study centres.

STUDY POPULATION

Phakic participants aged ≥40 years who participated in both examination time points.

OBSERVATION PROCEDURES

All participants at the baseline and at the mean 15-year follow-up visit underwent a detailed interview, anthropometry, blood pressure measurement, and comprehensive eye examination. Automated perimetry was attempted based on predefined criteria. Main outcome measures included development of any form of PACD, as defined by the International Society for Geographical and Epidemiological Ophthalmology (ISGEO), during the follow-up period in phakic participants, who did not have the disease at baseline.

RESULTS

We analyzed data obtained from 1,197 (81.4% out of available 1,470) participants to calculate the incidence of the disease. The mean age (standard deviation) of the study participants at the baseline was 50.2 (8.1) years, with 670 male (45.5%) and 800 female (54.4%) participants. The incidence rate per 100 person-years (95% confidence interval) for primary angle closure suspect, primary angle closure, and primary angle closure glaucoma was 8.8 (8.4, 9.2), 6.2 (5.9, 6.6), and 1.6 (1.4, 1.8), respectively. Thus, the incidence of all forms of PACD was 16.4 (15.9, 17) per 100 person-years. On logistic regression analysis, female gender was a significant risk factor whereas presence of myopia was protective.

CONCLUSIONS

This study reports long-term incidence of PACD from rural India. It has implications for eye health care policies, strategies, and planning.

The Singapore Asymptomatic Narrow Angles Laser Iridotomy Study: Five-Year Results of a Randomized Controlled Trial

PURPOSE

To examine the efficacy of laser peripheral iridotomy (LPI) in patients who received a diagnosis of primary angle-closure suspect (PACS).

DESIGN

Prospective, randomized controlled trial.

PARTICIPANTS

This multicenter, randomized controlled trial (ClinicalTrials.gov identifier, NCT00347178) enrolled 480 patients older than 50 years from glaucoma clinics in Singapore with bilateral asymptomatic PACS (defined as having ≥2 quadrants of appositional angle closure on gonioscopy).

METHODS

Each participant underwent prophylactic LPI in 1 randomly selected eye, whereas the fellow eye served as a control. Patients were followed up yearly for 5 years.

MAIN OUTCOME MEASURES

The primary outcome measure was development of primary angle closure (PAC; defined as presence of peripheral anterior synechiae, intraocular pressure [IOP] of >21 mmHg, or both or acute angle closure [AAC]) or primary angle-closure glaucoma (PACG) over 5 years.

RESULTS

Of the 480 randomized participants, most were Chinese (92.7%) and were women (75.8%) with mean age of 62.8 ± 6.9 years. Eyes treated with LPI reached the end point less frequently after 5 years (n = 24 [5.0%]; incidence rate [IR], 11.65 per 1000 eye-years) compared with control eyes (n = 45 [9.4%]; IR, 21.84 per 1000 eye-years; P = 0.001). The adjusted hazard ratio (HR) for progression to PAC was 0.55 (95% confidence interval [CI], 0.37-0.83; P = 0.004) in LPI-treated eyes compared with control eyes. Older participants (per year; HR, 1.06; 95% CI, 1.03-1.10; P < 0.001) and eyes with higher baseline IOP (per millimeter of mercury; HR, 1.35; 95% CI, 1.22-1.50; P < 0.0001) were more likely to reach an end point. The number needed to treat to prevent an end point was 22 (95% CI, 12.8-57.5).

CONCLUSIONS

In patients with bilateral asymptomatic PACS, eyes that underwent prophylactic LPI reached significantly fewer end points compared with control eyes over 5 years. However, the overall incidence of PAC or PACG was low.

Progression rate to primary angle closure following laser peripheral iridotomy in primary angle-closure suspects: a randomised study

AIM

To report the progression rate (PR) to primary angle closure (PAC) following laser peripheral iridotomy (LPI) in PAC suspects (PACS).

METHODS

Prospective, randomized controlled interventional clinical trial conducted at the Handan Eye Hospital, China. Totally 134 bilateral PACS, defined as non-visibility of the posterior trabecular meshwork for ≥180 degrees on gonioscopy were randomly assigned to undergo LPI in one eye. Gonioscopy and Goldmann applanation tonometry were performed prior to, on day 7 and 12mo post LPI.

RESULTS

Eighty of 134 patients (59.7%) could be followed up at one year. The mean intraocular pressure (IOP) in treated eyes was 15.9±2.6 mm Hg at baseline, 15.4±3.0 mm Hg on day 7; 16.5±2.9 mm Hg at one month, and 15.5±2.9 mm Hg at 12mo; the IOP in untreated eyes was similar (P=0.834). One or more quadrants of the angle opened in 93.7% of the LPI treated eyes, but 67.0% (53/79) remained closed in two or more quadrants. The PR to PAC in untreated eyes was 3.75% and one developed acute angle-closure glaucoma (AACG); the PR to PAC in treated eyes was 2.5% and none had developed peripheral anterior synechia (PAS) or AACG.

CONCLUSION

LPI can open some of the occludable angle in the majority of eyes with PACS, but 67% continue to have non-visibility of the trabecular meshwork for over 180 degrees.

Clinical observation of macular choroidal thickness in primary chronic angle-closure glaucoma

PURPOSE

To comparatively analyze differences in macular choroidal thickness and volume in primary chronic angle-closure glaucoma (PACG) eyes.

METHODS

Thirty-one PACG patients were sequentially selected for this case-control study. Thirty-one eyes with PACG were included in group A, 31 fellow eyes were included in group B, and group C included 67 normal eyes. Enhanced-depth imaging optical coherence tomography (EDI-OCT) was used to measure choroidal thickness and volume.

RESULTS

The choroidal thicknesses and volumes of the central subfield macula (CSM), nasal inner macula (NIM), temporal inner macula (TIM), inferior inner macula (IIM), temporal outer macula (TOM), inferior outer macula (IOM), and mean macula (MM) in group A were all higher than those in group C (P < 0.05). The choroidal thicknesses and volumes of the NIM, superior inner macula (SIM), IIM, nasal outer macula (NOM), and MM in group B were all higher than those in group C (P < 0.05). No statistically significant differences were found between groups A and B (P > 0.05). The choroidal thicknesses of different macular regions in group A were not correlated with the mean defect (MD).

CONCLUSION

Increased macular choroidal thickness may be a common anatomical characteristic of PACD eyes. Macular choroidal thickness is not a good marker for assessing PACG severity.

Repeatability and Reproducibility of Anterior Chamber Angle Measurement with Swept-Source Optical Coherence Tomography in Patients with Primary Angle Closure Suspect

Purpose: To evaluate the inter- and intra-observer reliability of anterior chamber (AC) angle measurements obtained by swept-source optical coherence tomography (SS-OCT).Methods: Forty-eight consecutive patients diagnosed with primary angle closure suspect (PACS) were included. Three masked observers at different training levels (one glaucoma specialist, one ophthalmology resident, and one pre-medical college student) measured 192 SS-OCT images of the PACS patients. One observer (the glaucoma specialist) repeated measurements 1 week later. SS-OCT parameters included: Anterior segment volume, including corneal, AC, and iris volume; anterior segment dimensions, including AC depth and width (ACD, ACW), and lens vault (LV); and angle parameters, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), and the trabecular iris angle (TIA). Intraclass correlation coefficients (ICCs) were used to measure reliability.Results: For inter-observer reproducibility, ICCs of corneal, AC, and iris volumes were 0.952 to 0.998. ICCs of ACD at all axes were above 0.989. ICCs of ACW and LV were smallest in the 90°-270° axis (0.751 and 0.768) but not significantly different from other axes. ARA, TISA, and TIA at all angles had significantly smallest ICCs 250 µm from the scleral spur compared with 500 µm and 750 µm. The ICCs comparing observers with different training levels had similar ranges and followed similar trends. For intra-observer repeatability, the smallest ICC was 0.843. Decreasing AC depth correlated with increased inter-observer reproducibility.Conclusions: We found excellent intra-observer repeatability for all SS-OCT parameters. Angle measurements have more variation among the observers when taken 250 µm from the scleral spur. Shallow AC might lead to more variability for angle parameters. Non-expert observers may be recruited for high-quality image grading with standard training.

Health care cost and benefits of artificial intelligence-assisted population-based glaucoma screening for the elderly in remote areas of China: a cost-offset analysis

Background

Population-based screening was essential for glaucoma management. Although various studies have investigated the cost-effectiveness of glaucoma screening, policymakers facing with uncontrollably growing total health expenses were deeply concerned about the potential financial consequences of glaucoma screening. This present study was aimed to explore the impact of glaucoma screening with artificial intelligence (AI) automated diagnosis from a budgetary standpoint in Changjiang county, China.

Methods

A Markov model based on health care system’s perspective was adapted from previously published studies to predict disease progression and healthcare costs. A cohort of 19,395 individuals aged 65 and above were simulated over a 15-year timeframe. Fur illustrative purpose, we only considered primary angle-closure glaucoma (PACG) in this study. Prevalence, disease progression risks between stages, compliance rates were obtained from publish studies. We did a meta-analysis to estimate diagnostic performance of AI automated diagnosis system from fundus image. Screening costs were provided by the Changjiang screening programme, whereas treatment costs were derived from electronic medical records from two county hospitals. Main outcomes included the number of PACG patients and health care costs. Cost-offset analysis was employed to compare projected health outcomes and medical care costs under the screening with what they would have been without screening. One-way sensitivity analysis was conducted to quantify uncertainties around model results.

Results

Among people aged 65 and above in Changjiang county, it was predicted that there were 1940 PACG patients under the AI-assisted screening scenario, compared with 2104 patients without screening in 15 years’ time. Specifically, the screening would reduce patients with primary angle closure suspect by 7.7%, primary angle closure by 8.8%, PACG by 16.7%, and visual blindness by 33.3%. Due to early diagnosis and treatment under the screening, healthcare costs surged dramatically to $107,761.4 dollar in the first year and then were constantly declining over time, while without screening costs grew from $14,759.8 in the second year until peaking at $17,900.9 in the 9th year. However, cost-offset analysis revealed that additional healthcare costs resulted from the screening could not be offset by decreased disease progression. The 5-, 10-, and 15-year accumulated incremental costs of screening versus no screening were estimated to be $396,362.8, $424,907.9, and $434,903.2, respectively. As a result, the incremental cost per PACG of any stages prevented was $1464.3.

Conclusions

This study represented the first attempt to address decision-maker’s budgetary concerns when adopting glaucoma screening by developing a Markov prediction model to project health outcomes and costs. Population screening combined with AI automated diagnosis for PACG in China were able to reduce disease progression risks. However, the excess costs of screening could never be offset by reduction in disease progression. Further studies examining the cost-effectiveness or cost-utility of AI-assisted glaucoma screening were needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11097-w.

Progression of Primary Angle Closure Suspect to Primary Angle Closure and Associated Risk Factors: The Handan Eye Study

Purpose

To investigate the progression of angle closure from primary angle closure suspect (PACS) and associated risk factors over five years in rural Chinese adults.

Methods

In this population-based cohort study, subjects aged ≥30 years old with unilateral or bilateral PACS at baseline of the Handan Eye Study who participated in the follow-up and had undergone baseline and follow-up gonioscopic examinations were included. The progression of angle closure was defined as the presence of primary angle closure (PAC)/primary angle-closure glaucoma (PACG) during the follow-up in subjects with PACS at baseline. Ocular data from the right eye were used for cases with bilateral PACS and unilateral PACS in the right eye at baseline. For those with unilateral PACS in the left eye at baseline, ocular data from the left eye were used. Demographic information, ocular conditions, personal history, and systemic comorbidities were compared between the progression and nonprogression groups. Univariate and multivariate logistic regression was performed to identify the baseline risk factors for progression of angle closure.

Results

In total, 526 subjects (111 male, 415 female) with baseline PACS were finally enrolled. The overall progression of PACS to angle closure was 32 cases (31 PAC, 1 PACG). Logistic regression analysis identified narrower mean angle width (P < 0.001) to be associated with the progression.

Conclusions

We report the progression from baseline PACS to PAC/PACG after five years. And baseline mean angle width was determined to be independent predictive risk factor for the progression of angle closure.