The biometric study in different stages of primary angle-closure glaucoma

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

BACKGROUND

To compare intraocular pressure (IOP) and anterior segment parameters between eyes with unilateral primary angle closure glaucoma (PACG) and their fellow eyes with primary angle closure (PAC) or primary angle closure suspect (PACS).

METHODS

Subjects underwent anterior segment imaging using 360-degree swept-source optical coherence tomography (SS-OCT, CASIA Tomey, Nagoya, Japan) and ocular investigations including gonioscopy and IOP measurement. Each SS-OCT scan (divided into 8 frames, 22.5 degrees apart) was analysed and an average was obtained for the following anterior segment parameters: iridotrabecular contact (ITC), angle opening distance (AOD750), iris thickness and curvature, anterior chamber width, depth and area (ACW, ACD and ACA) and lens vault (LV).

RESULTS

Among 132 unilateral PACG subjects (mean age: 62.91 ± 7.2 years; 59.1% male), eyes with PACG had significantly higher presenting IOP (24.81 ± 0.94 vs. 18.43 ± 0.57 mmHg, p < 0.001), smaller gonioscopic Shaffer grade (2.07 ± 0.07 vs. 2.31 ± 0.07, p < 0.001) and a greater extent of peripheral anterior synechiae (PAS, 1.21 ± 0.21 vs. 0.54 ± 0.16 clock hours, p = 0.001). PACG eyes also exhibited increased ITC, ITC area, greater LV and smaller AOD750, ACD and ACA (all p < 0.05). Using the forward stepwise regression model, an increase in 1 mmHg in presenting IOP before laser peripheral iridotomy (LPI) increases the odds of having PACG by 9% (95% confidence interval 5%-14%).

CONCLUSIONS

PACG eyes have higher presenting IOP, smaller anterior segment parameters, greater extent of PAS, and larger LV compared to their fellow eyes with angle closure. Narrower anterior chamber dimensions and higher presenting IOP before LPI may increase risk of chronic elevated IOP and glaucomatous optic neuropathy after LPI.

Social determinants of health and health disparities in glaucoma: A review

Social determinants of health and barriers to care can significantly impact patients' access to glaucoma care and treatment, resulting in disparities within disease presentation, progression, management, and treatment outcomes. The widespread adoption of electronic health record systems has allowed researchers and clinicians to further explore these relationships, identifying factors such as race, ethnicity, and socioeconomic status to be risk factors for more severe disease and lower treatment adherence. These disparities highlight potential targets for interventions to combat these disparities and improve overall patient outcomes. This article provides a summary of the available data on health disparities within glaucoma disease presentation, progression, management, treatment, and outcomes and discusses interventions to improve care delivery and outcomes among patients with glaucoma.

The Outbreak of Acute Primary Angle-Closure Cases During the COVID-19 Omicron Variant Pandemic at a Tertiary Eye Center in Shanghai

Purpose

This study aimed to investigate the outbreak of acute primary angle-closure (APAC) during the COVID-19 Omicron variant pandemic in Shanghai.

Methods

This single-center retrospective observational study included all newly diagnosed patients with APAC in Eye, Ear, Nose, and Throat Hospital of Fudan University from December 15, 2022, to January 14, 2023 (pandemic group) during the COVID-19 pandemic of Omicron Variant, and from November 15, 2021, to February 14, 2022 (control group) when the infection rate of COVID-19 is very low in Shanghai. Demographic features, intraocular pressure, axial length, anterior chamber depth, lens thickness and pupil diameter were compared between the two groups.

Results

A total of 223 patients (261 eyes) were included in the pandemic group and 75 patients (82 eyes) in the control group. The number of APAC patients and eyes in the pandemic group is 8.92-fold and 9.55-fold of the monthly average number in the control group. The onset dates of acute angle-closure were mainly between December 17 and December 31, 2022. In the pandemic group, 72.65% of patients with APAC had a recent COVID-19 infection. Among the COVID-19-positive patients, 72% suffered APAC attacks within 24h of the occurrence of COVID-19 symptoms and 92% within 3 days. The pandemic group showed a longer time from symptoms to treatment and larger pupil diameter than the control group (7.92 ± 6.14 vs 3.63 ± 2.93 days, p = 0.006; 4.53 ± 1.17 vs 3.78 ± 1.24 mm, p = 0.003, respectively).

Conclusion

An outbreak of APAC attack was observed in our eye center during the COVID-19 Omicron variant pandemic in Shanghai. There may be a correlation between the onset of APAC and new COVID-19 Omicron variant infection, but the exact reason needs to be investigated further.

Association of body mass index and PXDNL gene variants with acute primary angle closure in southern Chinese population

This study aimed to evaluate the association of body mass index (BMI) and the weight-related gene, peroxidasin-like (PXDNL), with acute primary angle closure (APAC) and primary angle-closure glaucoma (PACG) in southern Chinese population. Total 4700 study subjects (1024 APAC, 781 PACG, and 2895 control subjects) with complete ophthalmic examinations were enrolled into this study. The association of BMI with APAC, PACG and ocular biometric parameters was evaluated. Three PXDNL missense variants were genotyped by TaqMan assay, and their association with APAC and PACG was also investigated. Multivariable logistic regression analysis showed that BMI and body weight were significantly associated with both APAC and PACG (P < 0.01). Multiple linear regression analysis demonstrated that each 1 kg/m2 increased in BMI was associated with 0.038 mm increase in axial length, 0.018 mm increase in central anterior chamber depth, 0.002 mm increase in lens position, 0.012 mm increase in corneal diameter and 0.014 mm decrease in lens thickness among the APAC subjects (P < 0.001), but not with PACG. Genetic association analysis identified that PXDNL rs11985241-rs16916207 CT haplotype conferred a higher risk to APAC (OR = 1.25, P = 0.004) than the TG haplotype, but not with PACG. The APAC subjects carrying the rs11985241 C or rs16916207 T alleles showed significantly lower weight than those carrying the corresponding protective alleles. In summary, this study revealed that lower BMI could be associated with higher risk of APAC. PXDNL could be a new associated gene for APAC.

Risk Factors for Primary Angle-closure Glaucoma: A Systematic Review and Meta-analysis of 45 Studies

SIGNIFICANCE

This study summarized primary angle-closure glaucoma (PACG)-related factors across different dimensions.

OBJECTIVES

This review aimed at systematically summarizing the associated factors of PACG in published literatures.

METHODS

A systematic review and meta-analysis were conducted by searching the electronic databases including PubMed, EMBASE, and Web of Science from their inception to November 2021. The pooled risk estimates of continuous and categorical variables were calculated using weighted mean difference (WMD) and odds ratio (OR; 95% confidence intervals [CIs]), respectively.

RESULTS

We included 45 studies in this review. In the meta-analysis, intraocular pressure (WMD, 3.13; 95% CI, 2.37 to 3.89), anterior chamber depth (WMD, -0.52; 95% CI, -0.70 to -0.34), axial length (WMD, -0.77; 95% CI, -1.26 to -0.28), retinal nerve fiber layer (WMD, -21.23; 95% CI, -30.21 to -12.25), and spherical equivalent (WMD, 1.02; 95% CI, 0.66 to 1.38) were the most common ophthalmic anatomic factors, and lower body weight (WMD, -3.65; 95% CI, -6.48 to -0.82) was the most significant general morphological indicators. The presence of cataract (OR, 3.77; 95% CI, 3.46 to 4.11) and hyperlipidemia (OR, 1.10; 95% CI, 1.02 to 1.20) were significantly associated with PACG. Increased level of triglyceride (WMD, 0.17; 95% CI, 0.06 to 0.27) was associated with PACG. In addition, an association between short-term antidepressant exposure (OR, 1.36; 95% CI, 1.08 to 1.70) and acute angle-closure glaucoma was observed.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

This review identified a few consistent factors related to PACG, providing important information for primary care physicians, general ophthalmologists, and public health professionals to counsel their patients on PACG risks.

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.

New loci for refractive errors and ocular biometric parameters in young Chinese Han adults

Myopia has become a major public health issue with an increasing prevalence. There are still individuals who experience similar environmental risk factors and, yet, remain non-myopic. Thus, there might be genetic factors protecting people from myopia. Considering the opposite ocular characteristics of primary angle closure glaucoma (PACG) to myopia and possible common pathway between them, we propose that certain risk genes for PACG might act as a protective factor for myopia. In this study, 2,678 young adults were genotyped for 37 targeted single nucleotide polymorphisms. Compared with emmetropia, rs1401999 (allele C: OR=0.795, P=0.03; genotype in dominant model: OR=0.759, P=0.02) and rs1258267 (allele A: OR=0.824, P=0.03; genotype in dominant model: OR=0.603, P=0.01) were associated with low to moderate myopia and high myopia, respectively. Genotype under recessive model of rs11024102 was correlated with myopia (OR=1.456, P=0.01), low to moderate myopia (OR=1.443, P=0.02) and high myopia (OR=1.453, P=0.02). However, these associations did not survive Bonferroni correction. Moreover, rs1401999, rs1258267, and rs11024102 showed associations with certain ocular biometric parameters in different groups. Our study suggests that ABCC5, CHAT and PLEKHA7 might be associated with refractive errors by contributing to the regulation of ocular biometry, in terms of uncorrected results and their biological functions.

Association between retinitis pigmentosa and an increased risk of primary angle closure glaucoma: A population-based cohort study

Background

Retinitis pigmentosa (RP) is the most frequent retinal hereditary dystrophy and result in blindness if progresses. Several case reports have revealed the possible association between RP and primary angle-closure glaucoma (PACG). We conducted a population-based study to explore whether RP significantly increased the risk of PACG development.

Methods

Using the Taiwan National Health Insurance Research Database, we enrolled patients with RP into the RP group from 2001 to 2013 and included a comparison group of 1:4 age- and sex-matched individuals without RP. We performed a Cox regression analysis to estimate the crude and adjusted hazard ratios (HRs) of RP for PACG after adjustment for hypertension, diabetes, hyperlipidaemia, chronic kidney disease, and lens subluxation.

Results

We enrolled 6223 subjects with RP and 24892 subjects for comparison. The mean age of the cohort was 49.0 ± 18.1 years. The RP group had significantly higher percentages of diabetes mellitus, hypertension, and hyperlipidaemia. The cumulative incidence of PACG in patients with RP was 1.61%, which was significantly higher than that in the comparison group (0.81%, p < 0.0001). According to the univariate Cox regression analysis, the hazard of PACG development was significantly greater in the RP group, with an unadjusted HR of 2.09 (95% confidence interval [CI], 1.64–2.65). The increased risk persisted after adjusting for confounders (adjusted HR = 2.18; 95% CI, 1.76–2.72).

Conclusion

This nationwide population-based cohort study showed that people with RP are at a significantly greater risk of developing PACG than individuals without RP.

The Influence of 0.5% Tropicamide on Anterior Segment Parameters With CASIA2 in Emmetropic, Myopic, and Hyperopic Eyes

Aim: To evaluate the effects of 0.5% tropicamide on anterior segment parameters with the CASIA2 imaging device in emmetropic, myopic, and hyperopic eyes.

Methods: In this prospective study, a total of 125 subjects (34 emmetropic subjects, 57 myopic subjects, and 34 hyperopic subjects) at the Shanghai Eye and ENT Hospital of Fudan University were recruited from June 2021 to September 2021. The 0.5% tropicamide solution was used once every 5 min a total of 5 times for cycloplegia. The anterior segment parameters were recorded by CASIA2 before and after cycloplegia. Changes in anterior segment parameters were compared among the three refractive groups.

Results: Crystalline lens rise (CLR) and crystalline lens thickness (CLT) significantly decreased in all three refractive groups after cycloplegia (all p < 0.01). The anterior radius of lens (ARL) and anterior chamber depth (ACD) significantly increased in all three refractive groups after cycloplegia (all p < 0.01). Posterior radius of lens (PRL) significantly increased in hyperopic eyes after cycloplegia (p < 0.01) while it remained unchanged in emmetropic eyes and myopic eyes. Central corneal thickness (CCT), anterior chamber width (ACW), lens decentration (LD), and lens tilt (LT) remained unchanged after cycloplegia in all three refractive groups (all p > 0.05). Changes in CLR, CLT, ARL, PRL, and ACD in hyperopic eyes were greater than those in emmetropic eyes and myopic eyes (all p < 0.05).

Conclusion: Apart from various changes in anterior segment parameters after application by 0.5% tropicamide in all three refractive groups, significant changes in CLR, CLT, ARL, PRL, and ACD in hyperopic eyes should be noted for proper clinical interpretation.

Genetic Markers PLEKHA7, ABCC5, and KALRN Are Not Associated With the Progression of Primary Angle Closure Glaucoma (PACG) in Malays

Introduction PLEKHA7, ABCC5, and KALRN have been identified as susceptible genetic markers related to glaucoma. We aimed to investigate the association between the identified susceptible genetic markers PLEKHA7 rs11024102, ABCC5 rs17217796, and KALRN rs1392912 in the progression of primary angle-closure glaucoma (PACG) in Malay patients. Methods For this study, 163 Malay patients with PACG were recruited from April 2015 to April 2017 at Hospital Universiti Sains Malaysia and Hospital Raja Perempuan Zainab II, Kota Bharu. Venesection was performed. DNA was extracted using a commercial DNA extraction kit. The primer was optimized for rs11024102, rs17217796, and rs1392912 of the PLEKHA7, ABCC5, and KALRN genes, respectively. Polymerase chain reaction (PCR) was performed, and PCR products were purified. A DNA sequencer was used to identify polymorphisms. Progression was based on the agreement between the Advanced Glaucoma Intervention Study scoring system and the Hodapp-Parrish and Anderson staging system. The scoring was conducted on two reliable consecutive Humphrey visual fields (HVFs) during the recruitment period and two baseline HVFs obtained when the diagnosis was made. Based on the scoring, patients were grouped into progressed and non-progressed. A chi-square test was used to analyze the association between the genetic markers and the progression of PACG. Results One hundred and sixty-three Malay patients with PACG (58 men and 105 women) were recruited. Twenty-nine patients (18%) had visual field progression of PACG after a mean (SD) follow-up of 6.0 (1.0) years. The minor allele frequencies for PLEKHA7 rs11024102 (G/A), ABCC5 rs17217796 (C/G), and KALRN rs1392912 (A/G) were 0.44, 0.08, and 0.48, respectively. We found that rs11024102 (p=0.828), rs17217796 (p=0.865), and rs1392912 (p=0.684) were not associated with PACG progression in the Malay patients. Conclusion Although PLEKHA7 and ABCC5 were found to be genetic markers associated with the risk of PACG, they played no roles in PACG progression in the Malay population. Moreover, KALRN was not significantly associated with PACG progression. Other susceptible genetic markers may be responsible for PACG progression.

Etiologies and clinical characteristics of young patients with angle-closure glaucoma: a 15-year single-center retrospective study

Purpose

To investigate the etiologies and the clinical characteristics of angle-closure glaucoma (ACG) patients younger than 40 years old in Chinese.

Methods

Inpatients with diagnosis of ACG and diagnosed age younger than or equal to 40 years old, who were admitted in Eye, Ear, Nose, and Throat Hospital Fudan University from 2002 to 2017, were included in this retrospective non-comparative case series. The underlying causes and clinical features for all the patients were analyzed by comprehensive review of medical charts.

Results

A total of 298 patients (463 eyes) met the criteria, including 153 females (51.3%) and 145 males (48.7%); the mean age was 25.6 ± 13.0 years. Primary angle-closure glaucoma (PACG), uveitis, and anterior segment dysgenesis (ASD) were the top three etiologies in our patients, which accounted for 32.6%, 20.3%, and 15.1% of the total patients respectively. PACG mainly occurs after 30 years of age and ASD is the top reason of ACG in patients younger than 20 years old. Other known etiologies include iridocorneal endothelial syndrome, neovascular glaucoma, nanophthalmos, retinitis pigmentosa, spherophakia, bestrophinopathy, persistent fetal vasculature, iridociliary cysts, congenital retinoschisis, Marfan’s syndrome, retinopathy of prematurity, familial exudative vitreoretinopathy, congenital retinal folds, Coat’s disease, and neurofibromatosis.

Conclusions

We described the uncommon presentation of ACG in Chinese young patients. Although unusual, most of the etiologies could be identified. Therefore, more careful and comprehensive examinations are needed for early detection and timely treatment for young ACG patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05172-6.

Distribution and analysis of intraocular pressure and its possible association with glaucoma in children

PURPOSE

To analyze intraocular pressure (IOP) and glaucoma-associated factors in children.

METHODS

A total of 4438 children aged 7-16 years (2321 boys and 2117 girls) were included in this study. Various ophthalmologic [IOP, central corneal thickness (CCT), etc.] and demographic (body mass index, etc.) parameters were evaluated.

RESULTS

IOP increased between the ages of 7 and 9 years, peaking at 9 years. IOP increased after reaching a trough at 11 years and subsequently stabilized after 14 years. Girls exhibited thinner CCT (534.28 ± 30.84 µm vs. 537.04 ± 31.33 µm, P = 0.003), thicker lens thickness (3.56 ± 0.21 mm vs. 3.54 ± 0.20 mm, P = 0.001), shorter axial length (22.91 ± 0.93 mm vs. 23.32 ± 0.89 mm, P < 0.001), shallower anterior chamber depth (2.92 ± 0.27 mm vs. 3.00 ± 0.26 mm, P < 0.001), higher refraction (- 0.57 ± 1.48 D vs. 0.16 ± 1.35 D, P < 0.001), and higher mean corneal curvature (43.77 ± 1.39 vs. 43.03 ± 1.35, P < 0.001). Multivariable analysis assessed the following IOP-associated factors: thicker CCT [standardized correlation coefficient (SRC) = 0.201, P < 0.001), deeper anterior chamber depth (SRC = 0.059, P = 0.009), shorter axial length (SRC =  - 0.086, P = 0.036), lower mean corneal curvature (SRC =  - 0.123, P < 0.001), higher refraction (SRC =  - 0.090, P < 0.001).

CONCLUSION

IOP fluctuated in children, and a trend toward a higher mean IOP between the ages of 9 and 11 years, which stabilized after 14 years, was observed. IOP was associated with CCT, anterior chamber depth, axial length, lens thickness, mean corneal curvature, spherical equivalent, and systolic blood pressure.

Evaluation of Refractive Status and Ocular Biometric Parameters in Primary Angle Closure Disease

INTRODUCTION

The aim of the study was to evaluate the refractive status and ocular biometric parameters in subjects with angle closure in Malaysia.

METHODS

This cross-sectional study was conducted on 171 primary angle closure patients (268 eyes). Visual acuity, refraction, and ocular biometry (central anterior chamber depth [ACD], axial length [AL], and lens thickness) were recorded. Vitreous cavity length (VL) and relative lens position (RLP) were calculated.

RESULTS

A total of 92 Primary Angle Closure Suspect (PACS), 30 Primary Angle Closure (PAC), and 146 Primary Angle Closure Glaucoma (PACG) eyes were included. Chinese ethnicity formed the majority (n = 197, 73.5%), followed by Malay (n = 57, 21.3%) and Indian (n = 14, 5.2%). There was a significant female preponderance with a female to male ratio of 1.85. Mean age was 65.7 ± 7.7 years. Mean spherical equivalent was +0.33 ± 1.29 D. Approximately half (n = 137, 51%) of the eyes were hyperopic (spherical power ≥+0.5), with PACG having the highest percentage of hyperopia (n = 69, 50.4%). Myopia and emmetropia were present in 48 (17.9) and 83 (31%) eyes, respectively. Although AL and VL in myopia patients were significantly longer than emmetropic and hyperopic eyes (p < 0.001), the ACD was not significantly different (p = 0.427). While the RLP is smaller in myopic eyes, lens thickness was increased in hyperopic eyes. PACG was significantly higher in elderly patients compared to PACS and PAC (p = 0.005). A total of 37 (13.8%) eyes were blind (vision worse than 3/60) and 19 of them (51.3%) were female patients.

CONCLUSION

A decrease in RLP is predictive of angle closure disease in myopic eyes, whereas increased lens thickness contributes to angle closure disease in hyperopic eyes.

Cluster analysis reveals patterns of age-related change in anterior chamber depth for gender and ethnicity: clinical implications

Purpose

To identify patterns of age‐, gender‐ and refractive‐ related changes in Scheimpflug‐based anterior chamber depth across the central 8 mm of chamber width, to derive normative models, potentially useful for angle closure disease diagnosis.

Methods

This was a retrospective, cross‐sectional study. Scheimpflug photography was used to obtain anterior chamber depth measurements at 57 points across the central 8 mm of the chamber width from one eye of each healthy subject (male Caucasians (n = 189), female Caucasians (n = 186), male Asians (n = 165) and female Asians (n = 181)). Sliding window and nonlinear regression analysis was used to identify the age‐related changes in chamber depth. Hierarchical cluster analysis was used to identify test locations with statistically identical age‐related shifts, which were used to perform age‐correction for all subjects, resulting in normative distributions of chamber depth across the chamber width. The model was examined with and without the contribution of spherical equivalent refractive error.

Results

Distinct clusters, demonstrating statistically indistinguishable age‐related changes of chamber depth over time, were identified. These age‐related changes followed a nonlinear regression (fifth or sixth order polynomial). Females tended to have a greater rate of chamber depth shallowing. Incorporating refractive error into the model produced minimal changes to the fit relative to the ground truth. Comparisons with cut‐offs for angle closure from the literature showed that ageing alone was insufficient for identifying angle closure disease.

Conclusions

Age‐, ethnicity‐ and gender‐related differences need to be acknowledged in order to utilise anterior chamber depth data for angle closure disease diagnosis correctly. Ageing alone does not adequately account for the angle closure disease process.

Increased choroidal thickness in primary angle closure measured by swept-source optical coherence tomography in Caucasian population

PURPOSE

A role of the choroid has been suggested in the pathophysiology of angle closure. We assessed the choroidal thickness (CT) in Caucasian patients with primary angle closure (PAC) and in a subgroup of patients with plateau iris using swept-source optical coherence tomography (SS-OCT) compared to normal eyes.

METHODS

This prospective cohort study in a hospital-based population in a tertiary center compared consecutive patients with PAC to healthy controls. A subgroup analysis of patients with plateau iris was also performed. Choroidal thickness was measured by SS-OCT in the subfoveal area (SFCT) and at 1- and 3-mm eccentricity superiorly, inferiorly, nasally and temporally from the fovea.

RESULTS

Compared to the 25 eyes of 13 control patients [7 women, mean (SD) age, 56.6 (15.7) years], the 45 eyes of 25 patients with PAC [15 women, mean (SD) age, 55.7 (10.7) years] had a significantly increased SFCT. SFCT was 355.36 μm (SD 85.97) in PAC eyes versus 286.08 μm (SD 98.09) in control eyes (p = 0.009). The CT was also significantly increased compared to control eyes in other macular areas (p < 0.05), except at 3 mm temporal to the fovea. In the plateau iris subgroup, a not significant (except 3 mm nasal to the fovea) trend toward an increased CT was observed in all studied macular areas compared to control eyes.

CONCLUSION

In eyes of Caucasian patients with PAC, the CT is increased compared to controls. Increased CT could contribute to the pathophysiology of PAC with a possible choroidal expansion and dysfunction of choroidal ganglion cells.

Effect of Visibility of the Ciliary Body Processes on Ocular Biometric Parameters in Patients with Primary Angle Closure

PURPOSE

To evaluate the differences in ocular biometric parameters between eyes with primary angle closure (PAC) with and without visible ciliary body processes (CBP) (PAC+CBP and PAC-CBP) and normal open-angle controls.

STUDY DESIGN

Cross-sectional study.

METHODS

Eyes with PAC and normal open-angle controls underwent detailed ocular examinations and gonioscopy to determine the visibility of the CBP. The following ocular biometric parameters were determined using A-scan ultrasound biometry: axial length (AL), anterior chamber depth (ACD), lens thickness (LT), and vitreous length (VL). The lens-axial length factor (LAF) and relative lens position (RLP) were also calculated. Continuous variables were assessed by analysis of variance with Bonferroni correction. Multiple linear regression analysis was performed to adjust for confounding factors. Area under the receiver operating characteristic curves were calculated to determine the diagnostic capability of biometric parameters.

RESULTS

84 PAC+CBP eyes, 57 PAC-CBP eyes, and 32 normal open angle control eyes were evaluated. The means of the ocular biometric values were significantly different among the three groups. AL, ACD, LT, VL, LAF, and RLP were also significantly different among the three groups in the multivariate regression analysis. AL, ACD, and VL were lower in the PAC+CBP group and LT, RLP, and LAF were greater in the PAC+CBP group than in the PAC-CBP and control groups. LAF ≥ 2.4 is the cutting point with the highest sensitivity and specificity to differentiate PAC+CBP from PAC-CBP.

CONCLUSIONS

The ocular biometric parameters in the PAC+CBP group were more strongly associated with a crowded anterior segment than in the other groups. Visibility of CBP in PAC-affected eyes may serve as a surrogate for an anterior segment crowding mechanism and help to select the most appropriate treatment in individual cases.

Intraocular Pressure in General and Diabetic Populations From Southern China: the Dongguan Eye Study

Purpose

To investigate the distribution and risk factors for intraocular pressure (IOP) among general and diabetic populations in Southern China.

Methods

The study participants aged 40 years or older were enrolled from the Dongguan Eye Study, a population-based cross-sectional study from September 2011 to February 2012. Systemic and ophthalmic examinations were performed, and diabetes status was screened based on the American Diabetes Association diagnostic criteria (2010). IOP was measured by a noncontact tonometer per standardized protocol. Regression analyses were used to assess the association between potential risk factors and IOP.

Results

A total of 2112 subjects were included with a median age of 55 years. IOP for general population showed a near normal distribution with an average of 15.58 ± 3.27 mm Hg. Multiple regression analyses revealed that higher IOP was significantly correlated with younger age, higher body mass index (BMI), shorter height, higher blood pressure (BP), higher fasting blood glucose (FBG), higher low-density lipoprotein cholesterol (LDL-C), lower high-density lipoprotein cholesterol (HDL-C), and thicker central corneal thickness (CCT). There was no association between diabetes status and IOP after adjusting for possible confounders. IOP for diabetic participants showed a right-skewed distribution. Risk factors for IOP elevation in diabetes included female, younger age, higher BP, higher LDL-C, lower HDL-C, and thicker CCT.

Conclusions

The present study identifies risk factors for elevated IOP in general and diabetic populations. Younger age and lower HDL-C, as well as higher BP, LDL-C, and CCT were significant factors contributing to higher IOP, especially in the female diabetic population.

Relationship between ocular biometry and severity of primary angle-closure glaucoma: relevance for predictive, preventive, and personalized medicine

Background

Several ocular factors have been identified for primary angle-closure glaucoma (PACG), such as a small cornea, elevated intraocular pressure (IOP), shallow anterior chamber, and short axial length (AL). However, the relationship between the severity of PACG and various ocular parameters [IOP, anterior chamber depth, AL, central corneal thickness] is not fully understood.

Methods

A 7-year cross-sectional study. A total of 2254 eyes of 1312 PACG patients (females = 856 [1479 eyes] and males = 456 [775 eyes]) were included. A detailed eye examination was performed. The participants were categorized into gender subgroups followed by subdivision into three different severity groups according to their mean deviation (MD) of the visual fields results as follows: mild (MD ≤ 6 dB), moderate (MD 6-12 dB), and severe (MD > 12 dB) PACG. The associations of ocular biometry with severity of PACG were analyzed using paired Student's t test, multivariate linear regression, and logistic regression analysis.

Results

There was a significant positive correlation between the MD and AL in the female subgroup (B = 0.663, p = 0.001, 95%CI = 1.070 to 1.255) but not in the male subgroup. Increased AL levels (mild [OR = 1], moderate [OR = 1.047, p = 0.062, 95%CI = 0.947 to 2.462], and severe [OR = 1.274, p < 0.001, 95%CI = 1.114 to 1.457]) were only associated with the severity of PACG in females. Paired Student's t tests showed that the long AL female eyes have a higher MD value than in the short AL female eyes (mean difference = 3.09, t = 6.846, p < 0.001) in the same subjects, but not in the male subgroup (p = 0.648).

Conclusions

The AL was positively and significantly related to the severity of PACG in female but not male subjects. This finding refers to the PACG pathogenesis and suggests the use of AL assessment in glaucoma monitoring, diagnosis, and progression. This may contribute to further development of personalized strategies in preventive medicine.

Primary Angle-Closure Glaucoma With Normal Intraocular Pressure at the First Visit: Its Prevalence and Ocular Characteristics

PURPOSE

To investigate the prevalence of normal intraocular pressure (IOP) at first visit among patients with primary angle-closure glaucoma (PACG) and their ocular characteristics.

PATIENTS AND METHODS

We retrospectively reviewed patients with PACG in a referral center. According to untreated IOP, we divided PACG eyes into 2 groups: those with normal IOP and those with high IOP (>21 mm Hg) at the first visit.

RESULTS

One hundred sixty eyes of 160 Korean PACG patients were included. Sixty percent (97/160) of the patients had normal IOP at their first visit. The PACG patients with initially normal IOP had significantly longer axial length (mean±SD, 22.99±0.76 vs. 22.74±0.61) and deeper "true" anterior chamber depth (ACD) (2.09±0.27 vs. 1.82±0.33) than those with initially high IOP (both P<0.05). Multiple logistic regression revealed that deeper "true" ACD (per 0.1 mm; odds ratio, 1.38) and more hyperopic refractive errors (odds ratio, 1.48) were independent predictors of initially normal IOP in PACG eyes (P<0.05). The prevalence of disc hemorrhage was higher in PACG patients with initially normal IOP than in those with initially high IOP (29.9% vs. 14.3%, P=0.029).

CONCLUSIONS

Sixty percent of patients with PACG had normal IOP at their first visit. This suggests that without gonioscopy clinicians may misdiagnose PACG as normal tension glaucoma. ACD measurement can aid the diagnosis of PACG because even PACG eyes with initially normal IOP have shallow ACD.

B-mode sonographic evaluation of optic nerve sheath diameter and lens thickness in Nigerian adults with glaucoma

Objective

This study was done to investigate the effect(s) of glaucoma on the ocular optic nerve sheath diameter and lens thickness using B-mode ultrasonography.

Materials and methods

One hundred and twenty study participants were recruited; 60 subjects with glaucoma and 60 age- and sex-matched controls without glaucoma. The optic nerve sheath diameter and lens thickness of both eyes were measured using a linear high frequency transducer with frequency of 6.5–12MHz.

Results

The mean optic nerve sheath diameter of the glaucomatous eyes (3.57 ± 0.19mm and 3.59 ± 0.33mm on the right and left, respectively) were significantly thinner than that of controls (4.23 ± 0.34 mm and 4.26 ± 0.30 mm on the right and left, respectively; p < 0.001). There is increased mean lens thickness in the glaucomatous eyes (4.15 ± 0.43mm and 4.18 ± 0.46mm on the right and left, respectively) than in the controls (4.01 ± 0.56mm and 3.99 ± 0.45mm on the right and left, respectively) with a statistically significant difference seen in the left eye (p = 0.024).

Conclusion

B-mode ultrasound is a reliable tool of assessing the nerve sheath diameter and lens thickness in glaucoma. Optic nerve sheath diameter is reduced in glaucoma

Increased aquaporin-1 levels in lens epithelial cells with primary angle-closure glaucoma

AIM

To determine the levels of aquaporin-1 (AQP-1) in the lens epithelial cells (LECs) of primary glaucoma and to clarify its correlation with lens thickness.

METHODS

This study comprised 64 eyes of 64 patients with primary glaucoma, who were divided into 3 groups: 25 eyes of 25 patients with acute primary angle-closure glaucoma (APACG), 19 eyes of 19 patients with chronic primary angle-closure glaucoma (CPACG) and 20 eyes of 20 patients with primary open angle glaucoma (POAG). This study also included 12 eyes of 12 patients with senile cataract as controls. The levels of AQP-1 in LECs were examined by real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. The lens thickness was measured by A-scan ultrasonography.

RESULTS

The AQP-1 mRNA levels of LECs were 0.84±0.27, 0.69±0.34, 0.44±0.19 and 0.51±0.21 in APACG, CPACG, POAG and senile cataract group, respectively. The levels of AQP-1m RNA were significantly higher in PACG groups compared with those in senile cataract and POAG group (all P<0.05). The immunohistochemistry showed the AQP-1 expression were strong-positive in PACG groups, but weak-positive in senile cataract and POAG group. A positive correlation was found between AQP-1 mRNA levels and the lens thickness (r=0.645, P<0.001).

CONCLUSION

These findings show that the higher expression of AQP-1 in LECs may contribute to increased lens thickness, which might be associated with the occurrence and development of PACG.

Impact of Socioeconomic Status on the Diagnosis of Primary Open-Angle Glaucoma and Primary Angle Closure Glaucoma: A Nationwide Population-Based Study in Taiwan

Purpose

To understand the impact of socioeconomic status (SES) on the diagnosis of primary open-angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in Taiwan.

Methods

Subjects with glaucoma were identified from the National Health Insurance Research Database of year 2006, which included one million randomly selected insurants. Individuals who had ≥4 ambulatory visits within one year which had the diagnosis code of POAG (ICD-9-CM 365.11 or 365.12) or PACG (365.23) and concurrent prescription of anti-glaucoma medication or surgery were selected. Individual SES was represented by monthly income calculated from the insurance premium. Neighborhood SES was defined based on neighborhood household income averages. Urbanization level of habitation was categorized into 3 levels. The odds ratio of having POAG or PACG in subjects with different SES was evaluated by using multiple logistic regression analysis.

Results

In total, 752 and 561 subjects with POAG and PACG, respectively, who were treated on a regular basis, were identified. The diagnosis of glaucoma was affected by age, gender, frequency of healthcare utilization, individual SES, and urbanization level of habitation. With the adjustment of age, gender, healthcare utilization, neighborhood SES and level of urbanization, subjects with lower income were more likely to be diagnosed as PACG, but less likely as POAG.

Conclusions

Subjects with more frequent healthcare utilization were more likely to be diagnosed with glaucoma. Subjects with low SES were more susceptible to PACG, but subjects with high SES were more likely to be diagnosed as POAG. This information is useful for the design and target participant setting in glaucoma education and screening campaign to maximize the efficacy of limited resources in preventing glaucoma blindness.

Biometric parameters in different stages of primary angle closure using low-coherence interferometry

PURPOSE

To compare ocular biometric parameters using low-coherence interferometry among siblings affected with different degrees of primary angle closure (PAC).

METHODS

In this cross-sectional comparative study, a total of 170 eyes of 86 siblings from 47 families underwent low-coherence interferometry (LenStar 900; Haag-Streit, Koeniz, Switzerland) to determine central corneal thickness, anterior chamber depth (ACD), aqueous depth (AD), lens thickness (LT), vitreous depth, and axial length (AL). Regression coefficients were applied to show the trend of the measured variables in different stages of angle closure. To evaluate the discriminative power of the parameters, receiver operating characteristic curves were used. Best cutoff points were selected based on the Youden index. Sensitivity, specificity, positive and negative predicative values, positive and negative likelihood ratios, and diagnostic accuracy were determined for each variable.

RESULTS

All biometric parameters changed significantly from normal eyes to PAC suspects, PAC, and PAC glaucoma; there was a significant stepwise decrease in central corneal thickness, ACD, AD, vitreous depth, and AL, and an increase in LT and LT/AL. Anterior chamber depth and AD had the best diagnostic power for detecting angle closure; best levels of sensitivity and specificity were obtained with cutoff values of 3.11 mm for ACD and 2.57 mm for AD.

CONCLUSIONS

Biometric parameters measured by low-coherence interferometry demonstrated a significant and stepwise change among eyes affected with various degrees of angle closure. Although the current classification scheme for angle closure is based on anatomical features, it has excellent correlation with biometric parameters.

Evaluation of iridociliary and lenticular elasticity using shear-wave elastography in rabbit eyes

INTRODUCTION

A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine.

METHODS

Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer.

RESULTS

Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity.

CONCLUSIONS

Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.

Anterior segment OCT imaging in mucopolysaccharidoses type I, II, and VI

PURPOSE

To describe the anterior segment optical coherence tomography (AS-OCT) characteristics of patients with ocular manifestations of mucopolysaccharidoses type I (Hurler), II (Hunter), and VI (Maroteaux-Lamy).

METHODS

Prospective, observational study of nine consecutive patients with variants of mucopolysaccharidosis (MPS) attending the Paediatric Ophthalmology service at Manchester Royal Eye Hospital, UK. All patients underwent Visante AS-OCT imaging as part of their ophthalmic assessment.

RESULTS

Ocular involvement tended to be symmetrical. Angle-to-angle distance was significantly lower in MPS VI than in MPS I (P=0.04). Anterior chamber depth, angle opening distance, trabecular-iris space area, and scleral spur angle tended to be lower in MPS VI than in MPS I, but did not reach statistical significance. Corneal thickness in the central 0-2 mm zone was greater in MPS VI than in MPS I, approaching but not attaining statistical significance (P=0.07). The 2-5 and 5-7 mm zones were significantly thicker in MPS VI than MPS I (P=0.04, P=0.04). There was no difference in corneal thickness between MPS I and MPS VI in the peripheral 7-10 mm zone (P=0.57). Measurements of the patient with MPS II resembled the mean values of the MPS I group.

CONCLUSION

AS-OCT is valuable in quantifying anterior segment pathology in MPS. It suggests more crowded anterior segments and greater corneal thickness in patients with MPS VI than MPS I. AS-OCT is useful in evaluating the risk and mechanism of glaucoma in MPS patients, and may improve our assessment of the efficacy of systemic treatment.