Anterior chamber and angle characteristics in Chinese children (6-11 years old) with different refractive status using swept-source optical coherence tomography.

BACKGROUND: The anatomic structure of the anterior chamber (AC) helps to explain differences in refractive status in school-aged children and is closely associated with primary angle closure (PAC). The aim of this study was to quantify and analyze the anterior chamber and angle (ACA) characteristics in Chinese children with different refractive status by swept-source optical coherence tomography (SS-OCT). METHODS: In a cross-sectional observational study, 383 children from two primary schools in Shandong Province, China, underwent a complete ophthalmic examination. First, the anterior chamber depth (ACD), anterior chamber width (ACW), angle-opening distance (AOD), and trabecular-iris space area (TISA) were evaluated automatically using a CASIA2 imaging device. AOD and TISA were measured at 500, 750 µm nasal (N1 and N2, respectively), and temporal (T1 and T2, respectively) to the scleral spur (SS). Cycloplegic refraction and axial length (AL) were then measured. According to spherical equivalent refraction (SER), the children were assigned to hyperopic (SER > 0.50D), emmetropic (-0.50D < SER ≤ 0.50D), and myopic groups (SER ≤ -0.50D). RESULTS: Out of the 383 children, 349 healthy children (160 girls) with a mean age of 8.23 ± 1.06 years (range: 6-11 years) were included. The mean SER and AL were - 0.10 ± 1.57D and 23.44 ± 0.95 mm, respectively. The mean ACD and ACW were 3.17 ± 0.24 mm and 11.69 ± 0.43 mm. The mean AOD were 0.72 ± 0.25, 0.63 ± 0.22 mm at N1, T1, and 0.98 ± 0.30, 0.84 ± 0.27 mm at N2, T2. The mean TISA were 0.24 ± 0.09, 0.22 ± 0.09mm2 at N1, T1, and 0.46 ± 0.16, 0.40 ± 0.14mm2 at N2, T2. The myopic group had the deepest AC and the widest angle. Compared with boys, girls had shorter AL, shallower ACD, narrower ACW, and ACA (all p < 0.05). By Pearson's correlation analysis, SER was negatively associated with ACD, AOD, and TISA. AL was positively associated with ACD, ACW, AOD, and TISA. In the multiple regression analysis, AOD and TISA were associated with deeper ACD, narrower ACW, and longer AL. CONCLUSION: In primary school students, the myopic eyes have deeper AC and wider angle. ACD, ACW, AOD, and TISA all increase with axial elongation. ACA is highly correlated with deeper ACD.

In-depth analysis of eight susceptibility loci of primary angle closure glaucoma in Han Chinese.

Primary angle closure glaucoma (PACG) is a multifactorial disease with genetic predisposition. Primary angle closure (PAC) is the early stage of PACG and they share the same anatomical characteristics. We aimed to examine whether the PACG associated-genetic loci identified previously by genome-wide association study (GWAS) were also related to primary angle closure disease (PACD) in Han Chinese. This cross-sectional case-control study consisted of 232 PAC, 264 PACG and 306 controls. Eight single-nucleotide polymorphisms (SNPs) of PACG susceptibility loci within PLEKHA7, COL11A1, PCMTD1-ST18, EPDR1, CHAT, GLIS3, FERMT2, DPM2-FAM102A were genotyped using participants' blood samples. We excluded 3 SNPs for PAC analysis because the data has been reported using the same sample set. Anatomical parameters such as axial length (AL), anterior chamber depth (ACD) and lens thickness (LT) were included as phenotypes for the association analysis. Allelic and genotypic model tests were performed. Three among the eight SNPs were found to be significantly associated with PACG, e.g. PLEKHA7 rs11024102 in additive, dominant and recessive model; and both CHAT rs1258267 and DPM2-FAM102A rs3739821 in dominant model. CHAT rs1258267 showed marginal association with PAC in dominant model. Anatomical parameters were not found to link to the eight SNPs after Bonferroni multiple test correction. Our data suggest that PLEKHA7 and DPM2-FAM102A might exert effect in the late stage of the PACD, while CHAT may play a broad role in both early and late stages of the PACD.

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

PURPOSE: We sought to investigate anatomic mechanisms of angle narrowing by assessing ocular biometric determinants of anterior chamber angle width. DESIGN: Population-based cross-sectional study. METHODS: Subjects ≥50 years of age from the Chinese American Eye Study underwent a comprehensive ocular examination, including anterior segment optical coherence tomography imaging and ultrasound A-scan. Independent variables, including anterior chamber depth (ACD), lens vault (LV), iris curvature (IC), anterior chamber width, lens thickness, vitreous cavity depth, and axial length, and dependent variables, including angle opening distance, were measured in 1 randomly selected eye per subject. Univariable and multivariable regression models with standardized regression coefficients (SRCs) and semipartial correlation coefficients squares (SPCC2) were used to assess relative and unique contributions by independent variables to angle width. RESULTS: Two thousand two hundred twenty-five subjects (1433 women and 834 men) were included in the analysis. All biometric parameters except lens thickness differed between men and women (age-adjusted P < .001). In model 1A (R2 = 0.66), which included ACD, lens thickness, and vitreous cavity depth, ACD (SRC = 0.64, SPCC2 = 0.19) and IC (SRC = -0.26, SPCC2 = 0.041) were the strongest determinants of angle opening distance. In model 1B (R2 = 0.58), which included LV and axial length, LV (SRC = -0.46, SPCC2 = 0.1) and IC (SRC = -0.3, SPCC2 = 0.047) were the strongest determinants of angle opening distance. Determinants of angle width were similar in separate multivariable models for men and women. CONCLUSIONS: ACD, LV, and IC are the strongest determinants of angle width in Chinese Americans. Sex-related differences in angle width are explained by differences among biometric measurements. These results provide insights into anatomic mechanisms of angle narrowing and have important implications for quantitative assessments of angle closure eyes.

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.

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

PURPOSE: To characterize the relationship between mean and sectoral variation of anterior chamber angle (ACA) width using anterior segment optical coherence tomography (AS-OCT). METHODS: Subjects aged 50 years or older were identified from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. Each subject underwent a complete ocular examination including gonioscopy and AS-OCT imaging. Primary angle closure disease (PACD) was defined as inability to visualize pigmented trabecular meshwork in 3 or more quadrants. Four AS-OCT images from one eye per subject were analyzed and parameters describing ACA width were measured at 500 and 750 µm from the scleral spur: angle opening distance (AOD), trabecular iris space area (TISA), and scleral spur angle (SSA). The relationship between mean and sectoral variation of ACA width was assessed using locally-weighted scatterplot smoothing (LOWESS) regression and change-point analyses and Spearman correlation coefficients. RESULTS: 674 eyes (337 with PACD, 337 without PACD) from 674 subjects were analyzed. Overall, sectoral variation of ACA width decreased as mean ACA width decreased. This relationship was divided into two phases based on the change-point analysis. Sectoral variation of ACA width was strongly and significantly correlated (P < 0.001) with mean ACA width with below parameter-specific change points for most parameters: AOD500 (r = 0.599), AOD750 (r = 0.246), TISA500 (r = 0.734), TISA750 (r = 0.664), SSA500 (r = 0.661), SSA750 (r = 0.394). Correlations were weaker but still significant (P < 0.004) above these change points for most parameters: AOD500 (r = 0.321), AOD750 (r = 0.550), TISA500 (r = 0.122), TISA750 (r = 0.275), SSA500 (r = -0.036), SSA750 (r = 0.313). Correlations to the left and right of the change points strengthened when sectoral variation of ACA width was adjusted for mean ACA width. CONCLUSIONS: Correlations between mean and sectoral variation of ACA width strengthen as the severity of angle narrowing worsens. This relationship likely reflects anatomical changes related to chronic angle closure and may be relevant for refining current definitions and management of PACD.

Molecular Genetics of Glaucoma: Subtype and Ethnicity Considerations.

Glaucoma, the world's leading cause of irreversible blindness, is a complex disease, with differential presentation as well as ethnic and geographic disparities. The multifactorial nature of glaucoma complicates the study of genetics and genetic involvement in the disease process. This review synthesizes the current literature on glaucoma and genetics, as stratified by glaucoma subtype and ethnicity. Primary open-angle glaucoma (POAG) is the most common cause of glaucoma worldwide, with the only treatable risk factor (RF) being the reduction of intraocular pressure (IOP). Genes associated with elevated IOP or POAG risk include: ABCA1, AFAP1, ARHGEF12, ATXN2, CAV1, CDKN2B-AS1, FOXC1, GAS7, GMDS, SIX1/SIX6, TMCO1, and TXNRD2. However, there are variations in RF and genetic factors based on ethnic and geographic differences; it is clear that unified molecular pathways accounting for POAG pathogenesis remain uncertain, although inflammation and senescence likely play an important role. There are similar ethnic and geographic complexities in primary angle closure glaucoma (PACG), but several genes have been associated with this disorder, including MMP9, HGF, HSP70, MFRP, and eNOS. In exfoliation glaucoma (XFG), genes implicated include LOXL1, CACNA1A, POMP, TMEM136, AGPAT1, RBMS3, and SEMA6A. Despite tremendous progress, major gaps remain in resolving the genetic architecture for the various glaucoma subtypes across ancestries. Large scale carefully designed studies are required to advance understanding of genetic loci as RF in glaucoma pathophysiology and to improve diagnosis and treatment options.

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.

Vision-related Quality of Life in Glaucoma Patients and its Correlations With Psychological Disturbances and Visual Function Indices.

PURPOSE: The purpose of this study was to assess the vision-related quality of life (VR-QoL) in glaucoma patients and its correlations with psychological disturbances and visual function components. MATERIALS AND METHODS: The 25-item National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) and Hospital Anxiety and Depression Scale (HADS) questionnaires were administered to 428 Chinese glaucoma patients to evaluate their VR-QoL and anxiety and depression disorders, respectively. Sociodemographical and clinical factors were collected at the same time. Univariate analyses were used to investigate the associations between the variables and the VR-QoL. Multivariate linear regression analyses were used to identify the independent psychological and visual functional predictors of the VR-QoL. Standardized partial regression analyses were used to reveal the variables that mostly relevant to the VR-QoL. RESULTS: The composite score (mean±SD) was 71.88±14.44 for NEI VFQ-25 and 13.17±6.56 for HADS. Visual function indices, including best-corrected visual acuity and mean deviation of both eyes in addition to psychological symptoms including anxiety and depression were both correlated with VR-QoL significantly, even after adjusting for sociodemographical and clinical factors. Standardized partial regression analyses further suggested that psychological disorders, especially anxiety rather than visual function components, were mostly relevant to VR-QoL. CONCLUSIONS: Deterioration of vision impairment and visual field defects in addition to increased recognition of psychological disturbances reduce the VR-QoL of glaucoma patients significantly. Alleviating psychological symptoms, especially anxiety, perhaps have a greater influence on the improvement of VR-QoL.

Argon laser peripheral iridoplasty for chronic primary angle-closure and angle-closure glaucoma in caucasians.

PURPOSE: To investigate whether the peripheral thinning and shrinking of the iris as induced with Argon laser peripheral iridoplasty (ALPI) has an effect on intraocular pressure (IOP), angle structure and 3-D anterior segment (AS) morphology in Caucasians with chronic primary angle-closure (PAC) and primary angle-closure glaucoma (PACG). METHODS: Twenty-four eyes of 24 patients (age 67.7 ± 8.9 years; seven males; 17 females) diagnosed with PAC (n = 10) or PACG (n = 14) were assigned for ALPI prior to laser peripheral iridotomy (LPI) and consecutively enrolled in this prospective interventional study. Intraocular pressure (IOP) was measured with Goldmann applanation tonometry, angle structure with gonioscopy using the Shaffer grading system and AS morphology with the Pentacam rotating Scheimpflug camera prior to and 3 months after ALPI. Intraocular pressure (IOP)-lowering medication was not changed during follow-up. RESULTS: Intraocular pressure (IOP) changed statistically significantly from 18.8 ± 3.6 to 14.7 ± 3.1 mmHg (p < 0.001). Gonioscopy showed a statistically significant angle widening in all four quadrants: nasally from Shaffer 1.04 ± 0.98 to 2.54 ± 1.1 (p < 0.001), superiorly from 0.39 ± 0.66 to 1.58 ± 1.21 (p < 0.001), temporally from 0.87 ± 1.01 to 2.17 ± 1.24 (p = 0.001) and inferiorly from 1.22 ± 0.74 to 2.75 ± 0.9 (p < 0.001). Pentacam parameters like anterior chamber depth, volume and angle did not increase statistically significantly. CONCLUSION: Argon laser peripheral iridoplasty (ALPI) is a safe and effective procedure for reducing appositional angle-closure and thus IOP in nonacute PAC and PACG patients.

Comparison of Anterior Segment Optical Coherence Tomography Parameters Among Vietnamese, Chinese, and Whites.

PURPOSE: To evaluate the difference in anterior segment optical coherence tomography (AS-OCT) parameters among ethnic Vietnamese, Chinese, and whites. DESIGN: Cross-sectional study. METHODS: We prospectively recruited phakic nonglaucomatous participants (based on intraocular pressure < 21 mm Hg, normal optic nerve head and retinal nerve fiber, and cup-to-disc ratio < 0.6) of 3 ethnic groups-Vietnamese, Chinese, and white. AS-OCT parameters including angle (angle opening distance, trabecular-iris space area, and angle recess area), iris (iris thickness, iris area, and iris curvature [Icurv]), and anterior chamber parameters (anterior chamber depth, width [ACW], area, and lens vault [LV]) were obtained. A linear regression model with adjustment for age, sex, axial length, and pupillary diameter was used for analysis. Subgroup analysis was performed in closed- and open-angle subgroups, which were defined in eyes with gonioscopically visible posterior trabecular meshwork for less than 2 quadrants (closed) and equal to or more than 2 quadrants (open). RESULTS: Data were obtained from 126 Vietnamese, 124 Chinese, and 112 white participants. Mean (standard deviation) age of participants was 60.2 (11.8) years. Among overall subjects, Vietnamese had significantly smaller values in all angle and anterior chamber parameters than Chinese and white subjects (all P ≤ .001) except LV. Vietnamese had significantly higher Icurv than Chinese (B -0.065, P < .001) and white subjects (B -0.073, P < .001). In the open-angle subgroup, Vietnamese had significantly smaller angle and anterior chamber dimensions (P ≤ .001) and thicker iris (P < .001) than whites, whereas there was no significant difference in all parameters compared to Chinese except for smaller ACW in Vietnamese (P < .001). In the closed-angle subgroup, Vietnamese possessed smaller angle, smaller anterior chamber dimensions, and higher Icurv than Chinese and white subjects (P < .001). Vietnamese had significantly greater LV compared to Chinese (B -204.8, P = .001). CONCLUSION: Vietnamese subjects had more of the anatomic characteristics associated with risk for angle closure, including small anterior chamber dimension, high iris curvature, and high lens vault, compared to the other 2 ethnicities.

Investigation of Corneal Astigmatism in Chinese Patients With Primary Angle Closure Disease.

PURPOSE: The purpose of this study was to analyze the demographics and distribution of corneal astigmatism before lens extraction in patients with primary angle closure disease (PACD). METHODS: Preoperative partial coherence interferometry was performed in patients with PACD. The demographic and biometric data, including corneal astigmatism and keratometry (K), were recorded. RESULTS: The study comprised 808 cases (1001 eyes) with a mean age of 67.66±9.07 years, and the mean axial length was 22.55±0.89 mm. The mean corneal astigmatism was 1.08±0.78 diopter (D). Corneal astigmatism was between 0.25 D and 1.25 D in 66.50% of the eyes, 1.25 D or higher in 29.68% of the eyes and <0.25 D in 3.82% of the eyes. The corneal astigmatism of primary angle closure suspect (PACS), primary angle closure (PAC) and primary angle closure glaucoma (PACG) were 1.08±0.77 D, 0.98±0.62 D, and 0.89±0.69 D, respectively. In total, 50.60% of the eyes were classified as astigmatism against the rule (ATR), 28.69% of the eyes were with the rule, and 20.71% of the eyes were oblique. ATR astigmatism increased significantly with age (P<0.001). After matching, corneal astigmatism of PACD was 1.07±0.77 D, although it was statistically significantly higher than that of ARC (0.98±0.66 D, P=0.018), the 2 demonstrated no clinical difference. CONCLUSIONS: The results provide normative data of corneal astigmatism for PACD patients. Corneal astigmatism was mainly distributed between 0.25 D and 1.25 D. The findings largely concur with published results in age-related cataract subjects.

Comparison of Anterior Segment Parameters among Koreans, Chinese, and White Persons.

PURPOSE: To evaluate anterior segment (AS) parameters obtained by AS OCT within an urban Korean population and to compare them with measurements seen in Chinese and white participants. DESIGN: Prospective, cross-sectional, clinic-based study. PARTICIPANTS: Three gender- and age-matched cohorts of Korean, Chinese, and white participants recruited from general ophthalmology clinics in urban academic hospital settings. METHODS: Anterior segment OCT (Visante OCT; Carl Zeiss Meditec, Dublin, CA) was used to image the AS of all participants. Customized software was used to calculate AS parameters. MAIN OUTCOME MEASURES: Five angle parameters (AOD500, AOD750, TISA500, TISA750, ARA), 5 iris parameters (IT750, IT2000, ITCM, Iarea, Icurv), and 5 anterior chamber parameters (ACD, ACW, ACA, ACV, LV) were compared. Anterior vault (AV), relative AV, and relative LV were also calculated. These parameters were compared across all cohorts using a Kruskal-Wallis test. General linear models were built to assess pairwise comparison between Korean and Chinese and between Korean and white cohorts. Two-sided P values less than 0.05 were considered statistically significant. We also considered Bonferroni correction to control family-wise type 1 error (ɑFW = 0.05 / 18 = 0.003). RESULTS: The study included 132, 124, and 112 participants in the Korean, Chinese, and white cohorts, respectively. Korean participants showed AS parameters similar to those of Chinese participants, with the exception of having a smaller average ACW and a larger average IT2000. Compared with white persons, Koreans showed smaller angle parameters (trabecular-iris space area measured at 500 µm and 750 µm from the SS and angle recess area), anterior chamber parameters (ACD, ACW, ACA, ACV), and thicker irises (iris thickness measured at 750 µm and 2000 µm from the SS, maximum IT at the middle one third of the iris). The Korean cohort also was noted to show a smaller average LV compared with both Chinese and white cohorts. CONCLUSIONS: The Korean cohort demonstrated smaller average LV and relative LV.

Correlation between Intraocular Pressure and Angle Configuration Measured by OCT: The Chinese American Eye Study.

PURPOSE: To characterize the relationship between angle configuration measured by anterior segment optical coherence tomography (AS-OCT) and intraocular pressure (IOP). DESIGN: Cross-sectional study. PARTICIPANTS: Subjects aged 50 years or older were identified from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. METHODS: Each subject underwent a complete ocular exam including Goldmann applanation tonometry, gonioscopy, and AS-OCT imaging. Four AS-OCT images were analyzed per eye and parameters describing angle configuration were measured, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA). The relationship between AS-OCT measurements and IOP was assessed using locally-weighted scatterplot smoothing (LOWESS) regression and change-point analyses. MAIN OUTCOME MEASURES: Correlation between AS-OCT measurements and IOP. RESULTS: 702 eyes (382 closed angle and 320 open angle) from 555 subjects were analyzed. Mean IOP for angle closure eyes was 16.3 ± 3.9 mmHg and open angle eyes was 15.3 ± 2.7 mmHg. Mean IOP increased as AS-OCT measurements decreased for all parameters except TIA750. Once measurement values dropped below parameter-specific threshold values, AS-OCT measurements and IOP were significantly correlated (p < 0.05) for AOD500 (r = -0.416), AOD750 (r = -0.213), ARA500 (r = -0.669), ARA750 (r = -0.680), TISA500 (r = -0.655), TISA750 (r = -0.641), SSA500 (r = -0.538), and SSA750 (r = -0.208). There was no correlation between AS-OCT measurements and IOP in open angle eyes (p > 0.40). CONCLUSIONS: There is an anatomic threshold for angle configuration below which IOP is strongly related to the degree of angle closure. This finding suggests reconsideration of current definitions of angle closure and may be relevant for developing new OCT-based methods to identify patients at higher risk for elevated IOP and glaucoma.

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

Purpose: The purpose of this study was to evaluate the benefit of analyzing an increased number of anterior segment optical coherence tomography (AS-OCT) images on measurement values of various anterior segment parameters. Methods: Subjects for this cross-sectional study were recruited from the Chinese American Eye Study (CHES), a population-based study in Los Angeles, CA. Thirty-two AS-OCT images were acquired from one eye each of 83 consecutive subjects. Sixteen parameters were analyzed in each image, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), scleral spur angle (SSAngle), lens vault (LV), pupillary diameter (PD), anterior chamber depth (ACD), anterior chamber width (ACW), iris area (IA), and anterior chamber area (ACA). Data from 1, 2, 4, 8, 16, or 32 OCT images were averaged across subjects to calculate the range and mean of measurement values for each parameter. Results: Anatomical variations were poorly captured with fewer OCT images for AOD, ARA, TISA, SSAngle, IA, and LV. For these parameters, the range and mean of measurement values obtained from one OCT image deviated from 32-image values by up to 43.9% and 13.3% of the 32-image mean, respectively. These deviations decreased when additional OCT images were analyzed. Deviations from 32-image range and mean values were less pronounced regardless of image number for PD, ACD, ACW, and ACA, measuring up to 3.5% and 5.0%, respectively. Conclusions: A multi-image approach should be the standard in OCT-based studies of AOD, ARA, TISA, TIA, SSAngle, IA, and LV.

The Philadelphia Glaucoma Detection and Treatment Project: Detection Rates and Initial Management.

PURPOSE: To evaluate the detection rates of glaucoma-related diagnoses and the initial treatments received in the Philadelphia Glaucoma Detection and Treatment Project, a community-based initiative aimed at improving the detection, treatment, and follow-up care of individuals at risk for glaucoma. DESIGN: Retrospective analysis. PARTICIPANTS: A total of 1649 individuals at risk for glaucoma who were examined and treated in 43 community centers located in underserved communities of Philadelphia. METHODS: Individuals were enrolled if they were African American aged ≥50 years, were any other adult aged ≥60 years, or had a family history of glaucoma. After attending an informational glaucoma workshop, participants underwent a targeted glaucoma examination including an ocular, medical, and family history; visual acuity testing, intraocular pressure (IOP) measurement, and corneal pachymetry; slit-lamp and optic nerve examination; automated visual field testing; and fundus color photography. If indicated, treatments included selective laser trabeculoplasty (SLT), laser peripheral iridotomy (LPI), or IOP-lowering medications. Follow-up examinations were scheduled at the community sites after 4 to 6 weeks or 4 to 6 months, depending on the clinical scenario. MAIN OUTCOME MEASURES: Detection rates of glaucoma-related diagnoses and types of treatments administered. RESULTS: Of the 1649 individuals enrolled, 645 (39.1%) received a glaucoma-related diagnosis; 20.0% (n = 330) were identified as open-angle glaucoma (OAG) suspects, 9.2% (n = 151) were identified as having narrow angles (or as a primary angle closure/suspect), and 10.0% (n = 164) were diagnosed with glaucoma, including 9.0% (n = 148) with OAG and 1.0% (n = 16) with angle-closure glaucoma. Overall, 39.0% (n = 64 of 164) of those diagnosed with glaucoma were unaware of their diagnosis. A total of 196 patients (11.9%) received glaucoma-related treatment, including 84 (5.1%) who underwent LPI, 13 (0.8%) who underwent SLT, and 103 (6.2%) who were prescribed IOP-lowering medication. CONCLUSIONS: Targeting individuals at risk for glaucoma in underserved communities in Philadelphia yielded a high detection rate (39.1%) of glaucoma-related diagnoses. Providing examinations and offering treatment, including first-line laser procedures, at community-based sites providing services to older adults are effective to improve access to eye care by underserved populations.

Changes in Japanese eyes after laser peripheral iridotomy: an anterior segment optical coherence tomography study.

BACKGROUND: The aim was to investigate the changes in anterior segment parameters, as assessed by anterior segment optical coherence tomography in Japanese subjects after laser peripheral iridotomy (LPI). DESIGN: This was a prospective observational study. PARTICIPANTS: The participants include 72 subjects with angle closure including primary angle closure suspect (PACS), primary angle closure (PAC), and primary angle closure glaucoma (PACG). METHODS: Anterior segment optical coherence tomography parameters was measured by customized software. Complete data of 51 subjects were available for final analysis. MAIN OUTCOME MEASURES: These were the following parameters: angle opening distance, trabecular-iris space area, anterior chamber depth, width, area and volume (iris thickness, curvature, and area, and lens vault (LV). RESULTS: A total of 25 PACS, 17 PAC and 9 PACG were included. Mean age was 74.7 ± 6.7 years, and majority were women (80.4%). Following LPI, there was a significant increase in mean gonioscopic angle width (1.16 vs. 1.93, P < 0.001) and a corresponding increase in angle opening distance, trabecular-iris space area, and angle recess area (all P < 0.001). The anterior chamber area (P < 0.001), anterior chamber volume (P < 0.001) and anterior chamber depth (P = 0.003) increased significantly; and iris curvature (P < 0.001) was significantly reduced. There were no significant changes in anterior chamber width, LV, iris thickness and area. Age-adjusted and gender-adjusted analysis for predictors of percentage change in angle opening distance 750 showed significant association with greater baseline LV (ß = 0.32, P = 0.03). No significant differences were noted in the mean percentage change in parameters between the PACS and PAC-PACG. CONCLUSIONS: An increase in anterior chamber dimensions, angle widening and iris flattening; with a constant LV, iris thickness and iris area after LPI was demonstrated in Japanese eyes with angle closure.

Anterior Chamber Angle and Anterior Chamber Volume in a 40- to 64-Year-Old Population.

PURPOSE: To determine the distribution of the anterior chamber angle (ACA) and anterior chamber volume (ACV) in an Iranian population of 40- to 64-year-old people using the Pentacam. METHODS: In this cross-sectional study, multistage sampling was used to select 300 clusters, including 6,311 individuals from the city of Shahroud. All selected participants underwent examinations in one place. Optometric examinations, including measurement of visual acuity and refraction, and ophthalmologic examinations, including slit-lamp examination, were performed for all participants. Moreover, all patients underwent imaging with the Pentacam. RESULTS: The mean ACA and ACV was 34.3° (95% confidence interval [CI]: 34.1°-34.5°) and 139 µL (95% CI: 137.7-140.3), respectively. In a multiple linear regression model, the ACA was inversely correlated with age (coefficient=-0.08), lens thickness (coefficient=-1.38), corneal diameter (coefficient=-0.36), and corneal curvature (coefficient=-1.43), and directly correlated with the anterior chamber depth (ACD) (coefficient=6.59). In another model, ACV was inversely correlated with age (coefficient=-0.37), central corneal thickness (coefficient=-0.04), and spherical equivalent (coefficient=-1.15), and directly correlated with the ACD (coefficient=85.67), lens thickness (coefficient=14.15), corneal diameter (coefficient=4.80), corneal curvature (coefficient=18.43), ACA (coefficient=0.65), and intraocular pressure (coefficient=0.23). CONCLUSION: The findings of this study could be used as a reference for diagnosis and treatment in Iran and the Middle East region. Increase in age and decrease in the ACD were important factors associated with decreased ACA and ACV, although the correlation of other biometric components was also evaluated. Some of these components, such as the corneal curvature and lens thickness, had a significant relationship with these two variables.

Glaucoma in Asia: regional prevalence variations and future projections.

PURPOSE: To evaluate glaucoma prevalence and disease burden across Asian subregions from 2013 to 2040. METHODS: We conducted a systematic review and meta-analysis of 23 population-based studies of 1318 primary open angle glaucoma (POAG) cases in 66,800 individuals and 691 primary angle closure glaucoma (PACG) cases in 72,767 individuals in Asia. Regions in Asia were defined based on United Nations' (UN) classification of macro-geographic regions. PubMed, Medline and Web of Science databases were searched for population-based glaucoma prevalence studies using standardised criteria published to 31 December 2013. Pooled glaucoma prevalence for individuals aged 40-80 years was calculated using hierarchical Bayesian approaches. Prevalence differences by geographic subregion, subtype and habitation were examined with random effects meta-regression models. Estimates of individuals with glaucoma from 2013 to 2040 were based on the UN World Population Prospects. RESULTS: In 2013, pooled overall glaucoma prevalence was 3.54% (95% credible interval (CrI) 1.83 to 6.28). POAG (2.34%, 95% CrI 0.96 to 4.55) predominated over PACG (0.73%, 95% CrI 0.18 to 1.96). With age and gender adjustment, PACG prevalence was higher in East than South East Asia (OR 5.55, 95% CrI 1.52 to 14.73), and POAG prevalence was higher in urban than rural populations (OR 2.11, 95% CrI 1.57 to 2.38). From 2013 to 2040, South Central Asia will record the steepest increase in number of glaucoma individuals from 17.06 million to 32.90 million compared with other Asian subregions. In 2040, South-Central Asia is also projected to overtake East Asia for highest overall glaucoma and POAG burden, while PACG burden remains highest in East Asia. CONCLUSIONS: Across the Asian subregions, there was greater glaucoma burden in South-Central and East Asia. Sustainable public health strategies to combat glaucoma in Asia are needed.

Comparison of Ciliary Body Anatomy between American Caucasians and Ethnic Chinese Using Ultrasound Biomicroscopy.

PURPOSE: To compare the ciliary body morphology between the Caucasians and Chinese, and to determine the associated anterior segment parameters. METHODS: The study groups were comprised of four age- and gender-matched cohorts: American Caucasians, American Chinese, southern and northern mainland Chinese. Ultrasound biomicroscopy (UBM) was performed to assess the following measurements of the ciliary body: trabecular-ciliary process distance (TCPD), trabecular-ciliary process angle (TCA) and ciliary body thickness at 1 mm posterior to the scleral spur (CBT1). A-scan ultrasonography was used to measure lens thickness (LT) and relative lens position (RLP), defined as (ACD + LT/2)/AL. RESULTS: There were 109, 111, 115 and 117 subjects enrolled in the American Caucasian, American Chinese, and southern and northern mainland Chinese groups, respectively. Collectively, the Chinese had smaller TCPD (0.834 ± 0.234 versus 0.940 ± 0.236 mm, p < 0.001) and TCA (75.1 ± 17.9 versus 85.0 ± 21.5, p < 0.001) than Caucasians. No difference was found between the three Chinese subgroups, therefore they were combined as one for the following analyses. After multiple linear regression analysis, adjusting for age, gender, spherical equivalent (SE) and axial length (AL), TCPD and TCA were positively associated with CBT1 and RLP, but negatively correlated with LT in the whole sample. The ethnic Chinese had significantly smaller CBT1 (SRC = -0.177, p < 0.001) and RLP (SRC = -0.254, p < 0.001) than that of Caucasians. CONCLUSIONS: Compared with the Caucasians, the Chinese had a thinner ciliary body and a more anteriorly positioned lens, which may contribute to more anteriorly positioned ciliary processes in this population. These findings might help to explain the higher prevalence of angle closure in the Chinese.