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AIM—To evaluate the performance of limbal chamber depth estimation as a means of detecting occludable drainage angles and primary angle closure, with or without glaucoma, in an east Asian population, and determine whether an augmented grading scheme would enhance test performance.
METHOD—A two phase, cross sectional, community based study was condu...
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Methods:
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Purpose:
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Citations
... The investigator will also grade the angle opening according to a 7-point scale proposed by Foster et al, using reference images. 12 Patients will then receive the reference standard (gonioscopy), provided by an expert who will be masked to the evaluated tests (LACD and AS-OCT). The expert will be an ophthalmologist with glaucoma expertise and will judge if the angle is open or closed. ...
Introduction
Angle-closure is responsible for half of all glaucoma blindness globally. Patients with suspected glaucoma require assessment of the drainage angle by an experienced clinician. The goal of this study is to evaluate the diagnostic performance and cost-effectiveness of two non-contact tests, anterior segment OCT (Optical Coherence Tomography) (AS-OCT) and limbal anterior chamber depth for patients referred to hospital with suspected angle closure compared with gonioscopy by ophthalmologist.
Methods and analysis
Study design: prospective, multicentre, cross-sectional diagnostic accuracy study. Inclusion criteria: adults referred from community optometry to hospital with suspected angle closure. Primary outcome: Sensitivity and specificity. Secondary outcomes: Positive/negative likelihood ratios, concordance, cost-effectiveness, proportion of patients requiring subsequent clinical assessment by ophthalmologist. Sample size: 600 individuals who have been referred with suspected angle closure from primary care (community optometry). We will have a 95% probability of detecting the true sensitivity of either test to within ±3.5% based on a sensitivity of 90%. The study would also have a 95% probability of detecting the true specificity of either test to within ±5%, assuming a specificity of 75%.
Ethics and dissemination
Ethical Review Board approval was obtained. REC reference: 22/LO/0885. Our findings will be disseminated to those involved in eye care services. We will have a knowledge exchange event at the end of the study, published via the Health Technology Assessment web page and in specialist journals. The results will be presented at professional conferences and directly to patients via patient group meetings and the Glaucoma UK charity.
Trial registration number
ISRCTN15115867 .
... [15][16][17][18][19] Anterior segment biometry, shorter AL, shallow ACD, and small ACA have been identified to increase the risk of PACG. 7,17,18,20,21 Perhaps, anterior segment biometry plays a role as the risk factor for progression. ...
Objective:
To compare anterior segment biometry parameters in progress and non-progress primary angle closure glaucoma (PACG) among Malay and Chinese patients.
Materials and methods:
A cross-sectional study was conducted between November 2015 and December 2016 involving 75 patients with PACG (43 Malays and 32 Chinese) who were recruited from a single glaucoma center in Malaysia. Ocular examination included anterior segment biometry measurements on the selected eye. Axial length (AL) and anterior chamber depth (ACD) measurement was done using a noncontact partial coherence interferometer (IOL Master, Carl Zeiss, Germany). Anterior chamber angle (ACA) was measured by Anterior Segment-OCT (Spectralis Heidelberg, Germany). Humphrey visual field (HVF) 24-2 analysis of the same eye was conducted and compared with the HVF when diagnosis was made. Progression of PACG patients was assessed according to the Hodapp, Parrish and Anderson's (HPA) classification, they were then divided into progress and non-progress groups. Comparison of anterior segment biometry parameters between Malay and Chinese PACG patients with and without progression was analyzed using independent T test. Multivariate ANOVA analysis was used to compare the anterior segment parameters between progress and non-progress PACG patients, with adjustment for age, gender, lens status, family history and presence of diabetes mellitus.
Results:
Chinese PACG patients have significant shorter AL (22.18 mm ± 0.76) and narrower ACA (11.96° ± 6.00) compared to Malay PACG patients. Among the progress group, Chinese PACG patients have significant shorter AL, shallower ACD and narrower ACA compared to Malays. However, after controlling for confounding factors, there was significant difference in ACA between Malay and Chinese PACG. There was also no significant difference of ocular biometry measurement between Chinese and Malay patients in progress and non-progress group.
Conclusion:
There was racial influence in ocular biometry measurement in PACG patients. Chinese have significant narrower ACA compared to Malays. Serial AS-OCT monitoring is important in management of PACG.
How to cite this article:
Neoh FP, Azhany Y, Siti-Azrin AH, et al. Anterior Segment Biometry in Primary Angle Closure Glaucoma Patients with Visual Field Progression: Comparison between Malays and Chinese. J Curr Glaucoma Pract 2023;17(1):3-8.
... Using thorough interviewer-administered questions, the demographic information, history of ocular illnesses, and family history of glaucoma were gathered. Each participant underwent a standard ophthalmologic examination, which included measuring IOP with noncontact tonometry and performing distance visual acuity testing, best-corrected visual acuity testing, direct ophthalmoscopy, slit-lamp microscopy, and slit-lamp biomicroscopy with a 90D convex lens without pupil dilation (Foster et al. 2002, Foster et al. 2000. The details of eye examination and quality control were described elsewhere and also in the Supplemental Methods (Liu et al. 2022). ...
China faces increasing health risks from climate change. The structure and function of the eye and vision were affected by extreme heat and cold. The study aimed to evaluate the impacts of heatwaves and cold spells on glaucoma. A national cross-sectional study of the Rural Epidemiology for Glaucoma (REG-China) was conducted in ten provinces of China, and 36,081 adults aged 40 years or more were included. Glaucoma signs were assessed via a standard examination. A total of 15 heatwave definitions, based on intensity (95th to 99th percentiles of temperature distribution) and duration (≥2 days, 3 days, and 4 days), were used to quantify heatwave effects, and 6 cold spell definitions were defined based on threshold temperature percentile (5th and 10th) and duration (3 days, 5 days, and 9 days). Multivariable-adjusted logistic regression models paired with interaction analysis were performed to investigate the impacts of heatwaves and cold spells on glaucoma, and the dose-response relationships were assessed using a restricted cubic spline (RCS) model. Subgroup analysis was conducted stratified by gender, age, smoking status, occupation, and family history of glaucoma. The overall prevalence of glaucoma was 2.1% (95% CI 1.94–2.25%). Higher heatwaves were significantly correlated with higher OR of glaucoma, with the OR (95% CI) ranging from 1.014 (1.009, 1.018) to 1.090 (1.065, 1.115) by different definitions. Glaucoma was affected by heatwaves more strongly than by cold spells. The effects of both heatwaves and cold spells were higher in males than females and in smokers than nonsmokers. These results of the present study evoked the attention of prospective research to elucidate the relationship between extreme temperatures and eye diseases.
... Glaucoma suspects underwent further investigations, including fundus photography, Goldmann applanation tonometry, visual field and gonioscopy. 7 Distance VA was assessed monocularly using a 5 m standard logarithmic VA E chart (Tianjin ZhengDa Medical Care). Subjective refraction was performed on all participants with vision worse than 1.0 (less than 20/20) in either eye with an Autorefractor-Keratometer (KR8100, Topcon), and refinement of the sphere, cylinder and cylinder axis were performed until BCVA was obtained by the trained optometrists. ...
... Slit-lamp microscopy was conducted by trained ophthalmologists to identify LACD (graded as a percentage fraction of the thickness of the adjacent cornea in seven categories: 0%, 5%, 15%, 25%, 40%, 75% and ≥100%, referenced on standard photographs) and abnormal anterior segment according to Foster's study. 7 Fundus examination included the optic disk, retina, vessels and macula. In particular, the VCDR (referenced on standard photographs) was measured using direct ophthalmoscopy and slit-lamp biomicroscopy with a 90D convex lens for all participants without pupil dilation by a specific glaucoma expert in each province. ...
Objective
This study aimed to investigate the prevalence of glaucoma with associated factors in the rural populations of 10 provinces in China.
Design
A population-based cross-sectional study.
Methods
All participants aged 6 years or older from 10 provinces completed visual acuity testing, slit-lamp examination, ophthalmoscopy and non-contact tonometry. Glaucoma suspects underwent fundus photography, Goldmann applanation tonometry, visual field testing and gonioscopy. Glaucoma was determined according to the International Society of Geographical and Epidemiological Ophthalmology classification scheme. Associations of demographics and medical factors with glaucoma were assessed using multiple logistic regression models.
Results
From June 2017 to October 2018, 48 398 of 52 041 participants were included in the final analyses. The age-standardised prevalence of glaucoma was 1.7% (95% CI 1.55% to 1.78%) among the participants older than 6 years, which was 2.1% (95% CI 1.93% to 2.23%) in participants aged over 40 years. The constituent ratios of glaucoma were: 44.4% primary angle-closure glaucoma (PACG), 34.7% primary open-angle glaucoma, 2.6% congenital glaucoma and 18.3% other types of glaucoma. Increasing age, smoking, cerebral stroke, type 2 diabetes, higher education (college or more) and higher personal income were significant risk factors for PACG. The unilateral and bilateral blindness rates in the entire study population were 4.692% and 1.068%, respectively. A family history of glaucoma was a significant risk factor for the prevalence of glaucoma and blindness in at least one eye.
Conclusions
Rural populations have a high prevalence of glaucoma, which should be included in chronic disease management programmes in China for long-term care.
... However, indentation gonioscopy is a contact examination on the cornea, resulting in an uncomfortable feeling for most patients. Besides, it only provides qualitative outcomes which may be affected by the experience and proficiency level of the clinicians (Foster et al., 2000;Phu et al., 2019). ...
Indentation gonioscopy is commonly used in the clinic to evaluate peripheral anterior synechia (PAS) of angle closure glaucoma (ACG). The examination requires contacting with the cornea, resulting in an uncomfortable feeling for patients, and it only provides qualitative outcomes which may be affected by subjective judgment of the clinicians. Previous studies had reported to identify the presence of PAS by measuring the changes of morphological parameters of the anterior chamber angle (ACA) under the pupillary light reflex, by anterior segment optical coherence tomography (AS-OCT). However, this method was invalid for some subjects who had low sensitiveness to light. This article describes an air-puff dynamic anterior segment optical coherence tomography (DAS-OCT) system that can evaluate the presence of PAS in a non-contact approach. The peripheral cornea is deformed by an air puff jetted from the DAS-OCT, causing a transfer of force to the ACA, just as how indentation gonioscopy works. The dynamic changes of the ACA before and after the air puff are recorded by OCT. Ten eyes of normal subjects were enrolled in this study to validate the repeatability and availability of the measurements. Then, ten samples of the ACA from five subjects with ACG were recruited and were assigned into two groups, the non PAS group (NPAS) and PAS group, according to the results of gonioscopy. The ACA structural parameters including the angle opening distance at 750 μm to the scleral spur (AOD750) and the trabecular-iris space area at 750 μm anterior to the scleral spur (TISA750) were then calculated automatically by a custom-written algorithm. The intraclass correlation coefficient (ICC) of measured parameters was all above 0.85 for normal subjects, exhibiting good repeatability. For patients, both parameters showed significant differences between the two groups after the air puff, while no differences were observed before the air puff. AOD750dif and TISA750dif between two groups showed more significant differences, indicating that they could be used as indicators to identify the presence of PAS. In conclusion, the DAS-OCT system proposed in this study is demonstrated effective to identify the presence of PAS by measuring the changes of the ACA via a noncontact approach. It shows great potential for applications in guidance for diagnosis of angle closure glaucoma.
... В поиске предикторов ПЗУ важное значение имеет глубина передней камеры на периферии, или в зоне лимба (limbal chamber depth -LCD), определяемая методом биомикроскопии с расположением максимально узкого вертикального луча от осветителя под углом 60° к оси как процентное отношение расстояния от задней поверхности роговицы до передней поверхности радужки к толщине роговицы. P.J. Foster и соавторы констатировали высокие чувствительность (84%) и специфичность (86%) в обнаружении окклюзии УПК при степени закрытия менее 15% [41]. R. Sihota и соавторы усовершенствовали метод Van Herick для скрининга ПЗУ [42]. ...
ABSTRACT
Objective. 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 diagnos- tic parameters, in which a key role belongs to anterior segment optical coherence tomography (AS-OCT).
Keywords: primary angle closure, predictors of primary angle closure, disease progression in primary angle closure suspect, AS-OCT.
... In the year 2000, Foster et al. proposed a modified Van Herick grading system, trying to increase the diagnostic accuracy of the methodology. The original grade 1 was split into three sub-grades (i.e., 0%, 5% and 15%), and a new grade was introduced (i.e., 75%), to compensate for the gap between the traditional grades 3 and 4. In a population-based study from Mongolia, the authors found that the 15% cut-off (equal to the traditional grade 1) had a sensitivity and specificity of 84% and 86%, respectively, for the detection of occludable angles [66]. However, Baskaran et al., using the same 15% cut-off, found a sensitivity of 60.4%, in front of a 100% specificity. ...
... Good inter-observer reliability of the Van Herick technique has been previously reported [63,66]. However, although good reliability has been found for angles classified as grade 1 and 4, the same was not true for angles classified as grade 2 and 3, likely requiring further examinations to increase reliability [69]. ...
Assessment of the anterior chamber angle (ACA) is an essential part of the ophthalmological examination. It is intrinsically related to the diagnosis and treatment of glaucoma and has a role in its prevention. Although slit-lamp gonioscopy is considered the gold-standard technique for ACA evaluation, its poor reproducibility and the long learning curve are well-known shortcomings. Several new imaging techniques for angle evaluation have been developed in the recent years. However, whether these instruments may replace or not gonioscopy in everyday clinical practice remains unclear. This review summarizes the last findings in ACA evaluation, focusing on new instruments and their application to the clinical practice. Special attention will be given to the comparison between these new techniques and traditional slit-lamp gonioscopy. Whereas ultrasound biomicroscopy and anterior segment optical coherence tomography provide quantitative measurements of the anterior segment’s structures, new gonio-photographic systems allow for a qualitative assessment of angle findings, similarly to gonioscopy. Recently developed deep learning algorithms provide an automated classification of angle images, aiding physicians in taking faster and more efficient decisions. Despite new imaging techniques made analysis of the ACA more objective and practical, the ideal method for ACA evaluation has still to be determined.
... 16 However, large variations have been reported on the sensitivity and specificity of the vH technique. The sensitivity varied from 53% 15 to as high as 99% 17 while the specificity varied from 57% 18 to 96%. 19 These variations can be attributed primarily to the differences in methodology, prevalence of the target condition and the disease spectrum across the studies. ...
Purpose: To report on diagnostic accuracy of van Herick (vH) technique performed by a vision technician (VT) as well as on efficacy of a combination of vH technique and central anterior chamber depth (ACD) in detection of primary angle closure disease.
Methods: Data was obtained from two cohorts; rural clinic setting (n = 111), and rural population-based research setting (n = 888). Van Herick grading was performed by a VT in first cohort and a glaucoma specialist in second cohort. A reference standard four-mirror gonioscopy was performed by a glaucoma specialist in both cohorts. We did preferential sampling. Cut-off levels for vH technique and central ACD were grade 2 and 25th percentile value, respectively. Data from one eye per participant was analyzed.
Results: Three hundred and forty (34%) eyes were gonioscopically occludable. Area under receiver operating characteristic curve (95% confidence interval) for vH test was 0.83 (0.76, 0.9) and 0.81 (0.78, 0.84) in first and second cohorts, respectively. Simultaneous testing achieved sensitivity of 87.8% while sequential testing achieved specificity of 99.3%. Negative predictive value* of simultaneous testing was 98.3% compared to 96.6% of vH technique while positive predictive value* of sequential testing was 86% compared to 49.3% of vH technique. (*at 10% prevalence of gonioscopically occludable angle)
Conclusions: Diagnostic accuracy of vH grading was similar when performed by a VT and a glaucoma specialist. While test combination was effective to rule in, vH technique may suffice to rule out the disease. Implications of these findings for resource-constrained regions are discussed.
... A two phase, cross sectional, community based study was conducted by Foster, Devereux et alon rural and urban areas of Mongolia where 1717 diabetic subjects were examined. Occludable angles were identified in 140 subjects, 28 of these had PACG.15% were under grade 1 with a sensitivity and specificity of 84% and 86% respectively for the detection of occludable angles, thus proving the significance of occludable angle in diabetics [9]. ...
Introduction: Open angle Glaucoma is one of the causes of blindness in diabetic patients. Whether diabetes is a risk factor for angle closure glaucoma also is less thoroughly studied. Objectives: To assess the angle of anterior chamber in patients with type 2 diabetes mellitus. Materials and Method: 125 patients (250 eyes) who met the inclusion criteria were taken up for the study. Patients of both sexes and more than 40 years of age with Type 2 Diabetes Mellitus who do not come under the exclusion criteria were included. Results: In subjects with duration of diabetes <5 years, Grade 4 angle was found in 47.41% of eyes which was comparatively more than the other grades. When the duration of Diabetes was 5-10 years, 40% of the eyes had Grade 4 angle and 37.27% had Grade 3 angle. In subjects with >10 years duration of diabetes, 33.33% had Grade 3 angle. Grade 2 and Grade 4 angles were of equal distribution with 29.16% and Grade 1 was found to be less. The association of Grade 1 and Grade 3 angle with severe non-proliferative diabetic retinopathy was found to be statistically significant. Whereas, in patients with mild diabetic retinopathy and in moderate non-proliferative diabetic retinopathy Grade 4 angle is statistically significant. Conclusion: This study thus concludes the grade of angle of the anterior chamber decreases as the diabetic retinopathy advances.
... The participants underwent thorough ocular examination that included best-corrected visual acuity, anterior segment photography, Goldmann applanation tonometry, fundus examination, optic disc photography, visual field, objective refraction and subjective refraction. The depth of the peripheral anterior chamber was evaluated using the Van Herick technique [21]. Participants with a peripheral chamber depth less than one-third the corneal thickness were invited for gonioscope, A scan ultrasonography and ultrasound biomicroscopy (UBM, SW-3200S, SUOER, Tianjin, China) examinations. ...
Purpose
The formation of primary angle closure (PAC) and primary angle closure glaucoma (PACG) is regulated by a tissue remodeling pathway that plays a critical role in eye development. MicroRNAs (miRNAs) are powerful gene expression regulators and may exert their effects on tissue remodeling genes. This study investigated the associations between gene variants (single-nucleotide polymorphism, SNP) in miRNA binding sites in the 3’-UTR region of genes involved in eye development and PAC.
Methods
The sample consisted of 232 PAC subjects and 306 controls obtained from a population-based cohort in the Funing District of Jiangsu, China. The markers include 9 SNPs in the COL11A1, PCMTD1, ZNRF3, MTHFR, and ALPPL2 genes respectively. SNP genotyping was performed with a TaqMan-MGB probe using an RT-PCR system.
Results
Of the 9 SNPs studied, the frequency of the minor A allele of COL11A1 rs1031820 was higher in the PAC group than in the control group in allele analysis (p = 0.047). The genotype analysis indicated that MTHFR rs1537514 is marginally associated with PAC (p = 0.014). The CC genotype of rs1537514 was present solely in the PAC group. However, the differences lost significance after Bonferroni correction.
Conclusion
Our study reveals a possible association of COL11A1 and MTHFR with PAC in the Han Chinese population. These results will contribute to an improved understanding of the genetic basis of PACG.
