Changes in anterior segment parameters of normal subjects during accommodation using a Scheimpflug imaging system

Background: Accommodation changes ocular parameters, such as the anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle (ACA), and pupil diameter (PD), which can reflect a risk of angle-closure glaucoma. Previous studies of changes in ocular anterior segment parameters, have used high diopters or maximum amplitude. Here, we focused on normal accommodation at a reading distance of 30‒40 cm. The aim of this study was to assess changes in anterior segment parameters during a normal accommodative state, using a Scheimpflug imaging system. Methods: In this cross-sectional study, 40 emmetrope subjects (mean ± SD of age: 22 ± 4.0 years) who met the inclusion criteria and provided informed consent were enrolled. Clinical history, refraction, amplitude of accommodation, slit lamp examination, Goldman applanation tonometry, and Pentacam investigations were performed on all subjects. Accommodative and non-accommodative targets were induced via the Pentacam. Two seconds were allowed for accommodation or relaxation prior to measurements in each eye. Results: Eighty normal eyes were evaluated; a small but statistically significant change in ACV, ACA, and PD during accommodation (P < 0.01, < 0.01, and < 0.05, respectively) was observed. The ACD did not change substantially with accommodation (P = 0.29). The mean ± SD values of ACV, ACD, ACA, and PD before and after accommodation were 151.85 ± 24.04 mm3 and 145.38 ± 23.30 mm3, 2.87 ± 0.28 mm and 2.86 ± 0.27 mm, 35.06° ± 3.68° and 33.84° ± 3.72°, and 3.46 ± 0.57 mm and 3.41 ± 0.53 mm, respectively. Conclusions: Accommodation changes ocular parameters, such as ACV, ACA, and PD, in healthy young emmetropes. Interestingly, the ACD remains unaltered during accommodation. Nevertheless, although these changes were statistically significant, they were not clinically significant in our study.

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Comparative Study of the Effects of 1% Atropine on the Anterior Segment

Journal of Ophthalmology ◽

10.1155/2020/5125243 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Yue Zhou ◽

Xiao Bo Huang ◽

Qi Cai ◽

Jun Jie Li ◽

Yao Jia Xiong ◽

...

Keyword(s):

Anterior Chamber ◽

Univariate Analysis ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Muscle Thickness ◽

Ultrasound Biomicroscopy ◽

Cross Sectional ◽

Ciliary Process ◽

Before And After ◽

Anterior Segment Parameters

Purpose. To investigate the influences of atropine on changes in anterior segment geometry, as measured by ultrasound biomicroscopy in children. Methods. A prospective observational study was performed. Anterior segment parameters were obtained by UBM before and after the instillation of 1% atropine. Univariate linear regression was performed to identify the variables contributing to the changes in the trabecular meshwork-iris angle (TIA). Results. The study included 21 boys and 37 girls with a mean age of 10.79 ± 2.53 years. Anterior chamber parameters including the central anterior chamber depth, TIA, angle opening distance at 500 μm from the scleral spur, iris thickness 750 μm and 1500 μm from the scleral spur, trabecular-ciliary angle (TCA), trabecular-ciliary process distance, sclera-iris angle (SIA), and sclera-ciliary process angle significantly increased after cycloplegia ( P < 0.05 ). In contrast, the lens vault, iris cross-sectional area, and maximum ciliary muscle thickness significantly decreased after cycloplegia. Univariate analysis identified the change in TCA and the change in SIA and the TIA before mydriasis as determinants of the change in TIA. Conclusions. Atropine causes statistically significant changes in various anterior segment parameters in children. The change in anterior chamber angle is associated with the change in TCA and the change in SIA and the TIA before mydriasis.

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Understanding diagnostic disagreement in angle closure assessment between anterior segment optical coherence tomography and gonioscopy

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2019-314672 ◽

2019 ◽

Vol 104 (6) ◽

pp. 795-799 ◽

Cited By ~ 4

Author(s):

Natalia Porporato ◽

Mani Baskaran ◽

Tin A Tun ◽

Rehena Sultana ◽

Marcus Tan ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Cross Sectional Study ◽

False Positives ◽

Angle Closure ◽

Optical Coherence ◽

Cross Sectional ◽

Swept Source

Background/aimsAlthough being a more objective tool for assessment and follow-up of angle closure, reliability studies have reported a moderate diagnostic performance for anterior segment optical coherence tomography (OCT) technologies when comparing with gonioscopy as the reference standard. We aim to determine factors associated with diagnostic disagreement in angle closure when assessed by anterior segment swept source OCT (SS-OCT, CASIA SS-1000; Tomey, Nagoya, Japan) and gonioscopy.MethodsCross-sectional study. A total of 2027 phakic subjects aged ≥50 years, with no relevant previous ophthalmic history, were consecutively recruited from a community polyclinic in Singapore. Gonioscopy and SS-OCT (128 radial scans) for the entire circumference of the angle were performed for each subject. A two-quadrant closed gonioscopic definition was used. On SS-OCT images, angle closure was defined as iridotrabecular contact (ITC) to the extent of ≥35%, ≥50% and ≥75% of the circumferential angle. Diagnostic disagreements between both methods, that is, false positives or overcalls and false negatives or undercalls were defined, respectively, as gonioscopic open/closed angles inversely assessed as closed/open by SS-OCT.ResultsTwo hundred and seventy-two (14.7%) resulted in overcall results (false positives) when ≥50% of the angle circumference was closed using SS-OCT. These eyes had significantly wider (anterior chamber width, 11.7 vs 11.6 mm, p<0.001) and deeper (anterior chamber depth (ACD), 2.4 vs 2.2 mm, p<0.001) anterior chambers than eyes assessed by both methods as closed (true positives). Deeper ACD (OR 9.31) and lower lens vault (LV) (OR 0.04) were significantly associated with a false positive diagnosis in the multivariate analysis. Most of these cases had short (52.6%) or irregular (39%) ITC in SS-OCT images.ConclusionsWe found that anterior chamber dimensions, determined by ACD and LV, were factors significantly associated with diagnostic disagreement between anterior segment SS-OCT and gonioscopy in angle closure assessment.

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Evaluation of the Anterior Chamber Angle in Angle-Closure Suspect Patients by Anterior Segment Optical Coherence Tomography (AS-OCT) and Pentacam

10.21203/rs.3.rs-684174/v1 ◽

2021 ◽

Author(s):

Mohamed Salah El-Din Mahmoud ◽

Nosiba Essam ◽

Layla Mohamed Hammouda ◽

Ahmed Shawkat Mohamed

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Angle Closure ◽

P Value ◽

Optical Coherence ◽

Anterior Chamber Angle ◽

Cross Sectional ◽

Chamber Angle

Abstract Purpose: The study aims is to detect primary angle-closure glaucoma (PACG) suspects using both anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging. Methods: A prospective cross-sectional observational study on forty PACG suspect patients with a range of ages from 20 to 70 years. Angle imaging by AS-OCT (Optovue Inc., Fairmont, CA) with study parameters in the superior, inferior, nasal, and temporal quadrants were anterior chamber angle (ACA), angle opening distance at 750 µm (AOD750), and trabecular-iris space area at 750 μm (TISA). Also, angle imaging using Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) with study parameters were the anterior chamber angle (ACA), anterior chamber depth (ACD) and, anterior chamber volume (ACV). The angle evaluation was done before and after the mydriatic test.Results: As regarding AS-OCT, after the mydriatic test, we noticed a decrease in all parameters measured, some decreased significantly while others did not. A significant decrease was noticed in ACA (TIA750) in all quadrants (P value<0.001in nasal, 0.001in superior &temporal, 0.003 in inferior) and in TISA750 in the nasal quadrant only (P-value 0.004). AOD750 and TISA750 in the remaining quadrants also decreased but not significantly as ACA. As regarding Pentacam, all parameters decreased after the mydriatic test. ACA (P-value <0.001) and ACD (P-value 0.004) showed significant statistical decrease but ACV showed statistically non-significant decrease (P-value 0.558).Conclusions: AS-OCT and Pentacam are reliable investigations for the detection of PACG suspects which needs more close follow-up for a possible increase in IOP.

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Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients

Frontiers in Medicine ◽

10.3389/fmed.2021.732719 ◽

2021 ◽

Vol 8 ◽

Author(s):

Guihua Xu ◽

Guanrong Wu ◽

Zijing Du ◽

Shanqing Zhu ◽

Yunxiang Guo ◽

...

Keyword(s):

Anterior Chamber ◽

Age Groups ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Distribution Patterns ◽

Normal Range ◽

Cross Sectional ◽

Significant Difference ◽

Study Population ◽

Corneal Diameter

Purpose: To investigate the distribution of white-to-white (WTW) corneal diameter and anterior chamber depth (ACD) in Chinese myopia patients.Methods: This was a cross-sectional observational study conducted at five ophthalmic centers. Anterior segment biometry was performed in 7,893 eyes of the 7,893 myopic patients using Pentacam, and the WTW and ACD were recorded. The distribution patterns of WTW and ACD were evaluated and the correlation between WTW and ACD was analyzed statistically.Results: There were 4416 (55.95%) males and 3477 (44.05%) females. The age of the study population was 25.14 ± 5.41 years. Distribution of WTW was slightly positively skewed (Skewness = 0.0076, Kurtosis = 0.3944, KS P = 0.020) with a mean of 11.65 ± 0.38 mm and a 95% normal range of 10.91–12.39 mm. A significant difference in WTW was found among different myopia groups (P < 0.001). The ACD was normally distributed (Skewness = 0.899, Kurtosis = 0.027, KS P = 0.086). The mean ACD was 3.25 ± 0.26 mm and the 95% normal range of was 2.74–3.75 mm. A significant difference in ACD was also found among different myopia groups (P = 0.030). There was a significant correlation between WTW and ACD (r = 0.460, P < 0.001).Conclusions: In our study, 95% of the Chinese myopic patients had a WTW within 10.91–12.39 mm and an ACD within 2.74–3.75 mm. ACD and WTW were significantly different among different myopia, gender and age groups. WTW was positively correlated with ACD.

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Peripheral Anterior Chamber Depth and Screening Techniques for Primary Angle Closure Disease in Community Elderly Chinese

10.21203/rs.2.23915/v3 ◽

2020 ◽

Author(s):

Qin Luo ◽

Wenwen Xue ◽

Yin Yuan ◽

Chaowei Fu ◽

Jiangnan He ◽

...

Keyword(s):

Anterior Chamber ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Multivariate Logistic Regression Analysis ◽

Population Based ◽

Angle Closure ◽

Screening Methods ◽

Cross Sectional ◽

Primary Angle Closure ◽

Elderly Chinese

Abstract Background To investigate the distribution of peripheral anterior chamber depth (ACD) and the relationship between peripheral ACD and gonioscopy compared to other ocular parameters for primary angle closure disease (PACD) screening. Methods Cross-sectional study. Adults 50 and older were enrolled from a population-based study using cluster random sampling in Pudong New District, Shanghai. Remote ocular screening was performed with digital anterior eye structure photography. Van Herrick measurements were used to evaluate the peripheral ACD, the depth of the peripheral anterior chamber, and corneal thickness (CT), and the ACD to CT ratio was calculated. Subjects with peripheral ACD less than 0.5 CT were made follow-up appointments for clinical examination with gonioscopy. Receiver operating characteristic curves (ROC) were generated to show the performance of different tests in screening for primary angle closure disease (PACD). Results 2528 adults participated in the study with 91 patients diagnosed with PACD. 2463 subjects had valid data in the right eye available for analysis. The mean peripheral ACD values for men and women were significantly different: 1.04±0.46 (range 0.11-2.93) CT and 0.87±0.41 (range 0.12-2.96) CT respectively (t=-4.18; P<0.0001). Multivariate logistic regression analysis reveals that peripheral ACD declined by 0.31 CT (P<0.0001) per diopter of SE and was 0.19 CT (P<0.0001) shallower in women than in men (r2=0.1304, P<0.0001). Peripheral ACD performed best in screening for PACD. Conclusions Peripheral ACD measurement is recommended for PACD screening in community elderly Chinese.

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Anterior chamber angle imaging with swept-source optical coherence tomography: comparison between CASIAII and ANTERION

Scientific Reports ◽

10.1038/s41598-020-74813-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Poemen Pui-man Chan ◽

Gilda Lai ◽

Vivian Chiu ◽

Anita Chong ◽

Marco Yu ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Angle Closure ◽

Optical Coherence ◽

Anterior Chamber Angle ◽

Swept Source ◽

Scan Pattern ◽

Chamber Angle

Abstract This study compared the test–retest variabilities and measurement agreement of anterior chamber angle (ACA) dimensions measured by two anterior segment swept-source optical coherence tomography (SS-OCT)—the ANTERION (Heidelberg Engineering, Heidelberg, Germany) and CASIAII (Tomey, Nagoya, Japan). Thirty-eight subjects, 18 patients with primary angle closure and 20 healthy participants with open angles, were included. The mean age was 54.7 ± 15.8 years (range: 26–75 years). One eye of each subject was randomly selected for anterior segment imaging by ANTERION and CASIAII, using the same scan pattern (6 evenly spaced radial scans across the anterior segment for three times) in the same visit. The between- and within-instrument agreement and repeatability coefficients of angle open distance (AOD500), trabecular-iris space area (TISA500), lens vault (LV), scleral spur-scleral spur distance (SSD), anterior chamber depth (ACD), and pupil diameter (PD) were measured. The anterior and posterior boundaries of the cornea, iris, and lens were automatically segmented by the SS-OCT instruments; the scleral spur was manually located by a single masked observer. There were significant differences between ANTERION and CASIAII measurements; the SSD, PD, and ACD were smaller whereas AOD500 and TISA500 were greater in ANTERION compared with CASIAII (P < 0.001). Anterior segment measurements obtained from the two SS-OCT instruments showed strong associations (R2 ranged between 0.866 and 0.998) although the between-instrument agreement was poor; the spans of 95% limits of between-instrument agreement were ≥ 1.5-folds than the within-instrument agreement for either instrument. Whereas both SS-OCT instruments showed low test–retest measurement variabilities, the repeatability coefficients of AOD500, TISA500, ACD, and PD were slightly smaller for CASIAII than ANTERION (P ≤ 0.012).

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Quantification of Trabecular-Iris Contact and its Prevalence by Optical Coherence Tomography in a Healthy Caucasian Population

European Journal of Ophthalmology ◽

10.5301/ejo.5000919 ◽

2016 ◽

Vol 27 (4) ◽

pp. 417-422 ◽

Cited By ~ 4

Author(s):

José Ignacio Fernández-Vigo ◽

Lucía De-Pablo-Gómez-De-Liaño ◽

Cristina Fernández-Vigo ◽

Inés Sánchez-Guillén ◽

Enrique Santos-Bueso ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Anterior Chamber ◽

Refractive Error ◽

Axial Length ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Fourier Domain ◽

Optical Coherence ◽

Cross Sectional

Purpose To determine the prevalence of trabecular-iris contact (TIC) and quantify this contact in healthy Caucasian individuals using Fourier-domain optical coherence tomography (FD-OCT). Methods For this cross-sectional study, 2,012 eyes of 1,006 healthy subjects were recruited among individuals undergoing a routine ophthalmologic checkup. In each participant, age, sex, intraocular pressure, and spherical refractive error were first recorded along with anterior chamber depth and volume, central corneal thickness measured with the Pentacam, and axial length with the IOLMaster. Anterior chamber angle variables and the presence of TIC in the horizontal quadrants were determined by anterior segment FD-OCT (RTVue 100®). When TIC was observed, TIC length (TICL) and its percentage in relation to the length of the trabecular meshwork (TICL percentage) were also measured. Results Trabecular-iris contact in the horizontal quadrants was observed in 34 eyes of 25 patients, representing 1.6% of the total number of eyes examined. In this subgroup of individuals, mean age was 55.8 years, 84% were women, and spherical refractive error ranged from -0.25 to 8.25 D. Eyes with TIC showed an angle width of less than 23.2 degrees and axial length shorter than 23.7 mm. Mean TICL was 239 ± 79 μm (103-495 μm) and mean TICL percentage was 46.9% ± 13.9% (17.2%-76.3%). Conclusions The prevalence of TIC was low in this population. Fourier-domain optical coherence tomography emerged as useful to assess its prevalence and quantify the extent of TIC.

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Peripheral Anterior Chamber Depth and Screening Techniques for Primary Angle Closure Disease in Community Elderly Chinese

10.21203/rs.2.23915/v1 ◽

2020 ◽

Author(s):

Wenwen Xue ◽

Qin Luo ◽

Yin Yuan ◽

Chaowei Fu ◽

Jiangnan He ◽

...

Keyword(s):

Anterior Chamber ◽

Corneal Thickness ◽

Anterior Chamber Depth ◽

Multivariate Logistic Regression Analysis ◽

Population Based ◽

Cross Sectional Study ◽

Angle Closure ◽

Cross Sectional ◽

Primary Angle Closure ◽

Elderly Chinese

Abstract Purpose To investigate the distribution of peripheral anterior chamber depth (ACD) and the relationship between peripheral ACD and gonioscopy compared to other ocular parameters (peripheral ACD, spherical equivalent [SE], intraocular pressure [IOP]) for primary angle closure disease (PACD) screening in an elderly Chinese community. Methods Cross-sectional study. Adults 50 and older were enrolled from a population-based study using cluster random sampling in Pudong New District, Shanghai. Remote ocular screening was performed with digital anterior eye structure photography. Van Herrick measurements were used to evaluate the peripheral ACD, the depth of the peripheral anterior chamber, and corneal thickness (CT), and the ACD to CT ratio was calculated. Subjects with peripheral ACD less than 0.5 CT were made follow-up appointments for clinical examination with gonioscopy. Receiver operating characteristic curves (ROC) were generated to show the performance of different tests in screening for primary angle closure disease (PACD). Results 2528 adults participated in the study with 91 patients diagnosed with PACD. 2463 subjects had valid data in the right eye available for analysis. The mean peripheral ACD values for men and women were significantly different: 1.04±0.46 (range 0.11-2.93) CT and 0.87±0.41 (range 0.12-2.96) CT respectively (t=-4.18; P<0.0001). Multivariate logistic regression analysis reveals that peripheral ACD declined by 0.31 CT (P<0.0001) per diopter of SE and was 0.19 CT (P<0.0001) shallower in women than in men (r2=0.1304, P<0.0001). Peripheral ACD performed best in screening for PACD. Conclusions Peripheral ACD measurement is recommended for PACD screening in community elderly Chinese.

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‘Van Herick Plus’: a modified grading scheme for the assessment of peripheral anterior chamber depth and angle

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2018-312132 ◽

2018 ◽

Vol 103 (7) ◽

pp. 960-965 ◽

Cited By ~ 3

Author(s):

Ramanjit Sihota ◽

Neha Kamble ◽

Ajay K Sharma ◽

Anju Bhari ◽

Amisha Gupta ◽

...

Keyword(s):

Anterior Chamber ◽

Corneal Thickness ◽

Anterior Segment ◽

Anterior Chamber Depth ◽

Area Under The Curve ◽

Weighted Kappa ◽

Accurate Method ◽

Cross Sectional ◽

Vertical Slit ◽

Inferior Angle

AimTo evaluate the accuracy of a new, modified grading scheme involving a short vertical slit beam, at the inferior angle for peripheral anterior chamber depth (PAC) and angle estimation and its correlation with anterior segment optical coherence tomography (ASOCT).MethodsA cross-sectional study of consecutive phakic patients, above 40 years of age, was performed. Using a short, vertical slit beam not reaching the pupil, the inferior angle at the sclerolimbal junction was evaluated, photographed and assessed by a ratio of peripheral anterior chamber depth to peripheral corneal thickness (PAC:PCT) and iridocorneal angle (ICA) on ImageJ software. The inferior angle at the same meridian was also recorded on ASOCT.ResultsBased on the PAC:PCT ratio, the subjects were divided into four groups: I (<1/4), II (1/4-1/2), III (>1/2–1) and IV (>1). The clinically assessed angle by short vertical slit beam correlated well with ASOCT values, trabecular-iris angle (TIA) (r=0.918; p<0.001) and scleral spur angle (r=0.903, p<0.001). The mean difference between ICA and TIA on ASOCT was 0.7970; 95% limits of agreement:−5.7670 to 7.3610 (±1.96 SD). For angles graded narrow on ASOCT (TIA <200), using a cut-off of peripheral PAC:PCT <1/4, the area under the curve was 0.918 with a sensitivity of 85.2% and a specificity of 88.2%. There was good agreement between ImageJ parameters with those assessed subjectively on photograph of the slit beam examination by a glaucoma fellow (weighted kappa=0.74) as compared with a general ophthalmologist, where there was moderate agreement (weighted kappa=0.57).ConclusionA short, vertical slit lamp beam evaluation at the inferior angle is an easy and relatively accurate method for both peripheral anterior chamber depth and angle assessment. It correlated well with ASOCT and can be used as a more reliable screening tool to identify eyes with possibly occludable angles.

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