Disagreement between anterior segment optical coherence tomography devices in eyes with a shallow anterior chamber

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Methods Twenty-three patients were evaluated by gonioscopy before AS-OCT imaging. Anterior segment images were acquired under dark conditions using both Visante® and DRI OCT Triton®. The agreement of angle closure diagnosis between gonioscopy and AS-OCT was assessed with first-order agreement coefficients (AC1). Bland-Altman plots were used to assess the agreement of quantitative parameters obtained by both OCT devices. Results Significant differences were observed in all evaluated parameters. All angle-related measurements were higher with the DRI OCT Triton®, whereas all iris-related parameters were higher with the Visante®. Lens vault was significantly higher with the Visante® than with the DRI OCT Triton® (857.46 ± 279.38 µm vs. 310.68 ± 244.75 µm, p < 0.001). Anterior chamber width was significantly higher using DRI OCT Triton® than Visante® (11.91 ± 0.43mm vs. 11.42 ± 0.42 mm, p < 0.001). Agreement between devices ranged from good to excellent (ICC 0.61–0.90). Gonioscopy showed better agreement with the Visante® (AC1 = 0.52) than with the DRI OCT Triton® (AC1 = 0.12). Conclusion A substantial difference between parameters analyzed by AS-OCT devices was observed. gonioscopy anterior segment optical coherence tomography AS-OCT angle closure primary angle closure glaucoma Figures Figure 1 Figure 2 Figure 3 INTRODUCTION The anterior chamber anatomy was clinically evaluated using slit-lamp biomicroscopy and gonioscopy. However, gonioscopy is a time-consuming examination, is associated with substantial patient discomfort, and its grading may vary among clinicians. Moreover, it is difficult to document the test results, and there are several classifications of gonioscopic findings, which may confuse physicians.( 1 – 3 ) Anterior segment optical coherence tomography (AS-OCT) offers detailed real-time imaging of the anterior segment with high resolution. The method is frequently employed because it is contactless, rapid, semi-automatic, requires little operator involvement, and demonstrates consistent reproducibility.( 4 , 5 ) The Visante® OCT (Carl Zeiss Meditec, Dublin, USA) is a time-domain OCT device, introduced in 2006, specifically designed for anterior segment imaging.( 6 ) The DRI OCT Triton® (Topcon Corporation, Tokyo, Japan) is a swept-source OCT system introduced in 2015 for retinal imaging. With the optional anterior segment lens, it can produce B-scans up to 16 mm in length, enabling simultaneous visualization of opposite angles along the same axis.( 7 ) To date, no study in the literature compares the angular or anterior chamber measurements obtained with these devices. Therefore, the objective of this study was to assess the level of agreement between measurements obtained with the Visante® and the DRI OCT Triton® in eyes with shallow anterior chambers, as well as to evaluate potential discrepancies between the values obtained from both devices. MATERIALS & METHODS The Institutional Ethics Committee authorized the protocol, and all subjects provided written informed permission before being included in the study. The study was structured as an observational, cross-sectional design aimed at analyzing data obtained with two different types of AS-OCT devices. All participants were initially evaluated by a complete ophthalmological exam, including best-corrected visual acuity with manifest refraction, biomicroscopy, intraocular pressure measurement (IOP - Goldmann tonometry), and non-mydriatic fundoscopic evaluation. In addition, measurements of anterior chamber depth (ACD) and axial length (AXL) were obtained using the IOL Master® 500 (Carl Zeiss Meditec, Dublin, CA, USA). To minimize measurement bias, all images were acquired by a single examiner who was masked to the results of the other device, and gonioscopy was performed by a glaucoma specialist. All participants were attended at the glaucoma department for an evaluation of angle status and to validate laser peripheral iridotomy indication. Only subjects presenting a peripheral ACD to peripheral corneal thickness (PACD:PCT) ratio of less than 1/2 were enrolled in the study. Subjects with previous intraocular surgery, laser procedures (iridotomy or iridoplasty), or ocular trauma history were excluded. Gonioscopy In this protocol, only the initial eye under examination was included. Glaucoma experts performed the gonioscopy before AS-OCT evaluation. Each participant underwent gonioscopy with a Sussman four-mirror lens (Ocular Inst., Bellevue, USA). Examinations were conducted in dark conditions while maintaining the eye in primary gaze. A minimal light beam was applied to inspect the angle under high magnification, avoiding direct illumination of the pupil. The visibility of anatomical landmarks—such as Schwalbe’s line, anterior (non-pigmented) trabecular meshwork, posterior (pigmented) trabecular meshwork, scleral spur, and ciliary body band—was recorded during static gonioscopy. Indentation was subsequently performed to verify the presence of synechiae, imprints, or both. A quadrant was considered closed on gonioscopy when the pigmented trabecular meshwork was not visible during static evaluation. Patients were diagnosed with primary angle closure (PAC) if at least two quadrants were closed and either synechiae or appositional contact were present. Primary angle closure glaucoma was defined as the coexistence of PAC gonioscopic findings with glaucomatous optic neuropathy, characterized by localized or diffuse neuroretinal rim loss or retinal nerve fiber layer thinning on fundus examination. AS-OCT Anterior segment images were captured using a time-domain Visante® OCT and a swept-source DRI OCT Triton®, both performed under dark conditions (Fig. 1 ). Each image was centered on the pupil and acquired along the horizontal meridian (from 3 to 9 o’clock) as well as the vertical meridian (from 12 to 6 o’clock). If necessary, upper or lower eyelids were gently displaced during image capture. A masked examiner analyzed all AS-OCT images using ImageJ® software (V.1.50i). Only scans correctly centered and with discernible scleral spur (SS) were analyzed. The determination of SS was based on previously described criteria.( 8 ) All quantitative variables were measured after manually marking SS. The following parameters were assessed to compare the two OCT devices: angle opening distance at 250 µm and 500 µm from the SS (AOD250, AOD500), trabecular-iris space at 500 µm from the SS (TISA500), and trabecular-iris angle (TIA). The iris parameters measured were iris thickness at 750 µm (IT750) and 2000 µm (IT2000) from the SS, iris curvature (ICURVE), and iris area in the cross-sectional area of the full length of the iris (IAREA). The anterior chamber parameters evaluated were: lens vault, pupillary distance (PD), and anterior chamber width (ACW). The definitions of each parameter have been previously described.( 9 ) The ratio between PD and ACW (PD:ACW) was also calculated. A quadrant was classified as closed on AS-OCT when contact was observed between the iris and the corneoscleral surface located anterior to the scleral spur. Statistics Statistical analyses were conducted using Stata® software (version 15; StataCorp, College Station, USA). The McNemar test evaluated differences in the distribution of categorical variables. Depending on variable distribution, either a paired t-test or a Wilcoxon signed-rank test was applied. The first-order agreement coefficient (AC1) was applied to measure concordance among categorical variables. AC1 statistics were also employed to determine the level of agreement between the tests.( 10 ) Qualitative ratings of agreement statistics were used based on Landis and Koch.( 11 ) Intraclass correlation coefficient (ICC) and Bland-Altman plots were used to assess the agreement between quantitative parameters obtained by the devices.( 12 ) Given the exploratory nature of the study and a sample size close to 20 subjects, Bland–Altman analysis was applied for descriptive assessment of agreement. The sample size was considered sufficient to allow an approximate normal distribution of the differences, which was evaluated prior to analysis. RESULTS Initially, 44 eyes were included, and 21 eyes were excluded from the study due to unclear identification of SS in at least one quadrant of any AS-OCT. Six eyes presented a poor-quality image in Visante® OCT scans, twelve in DRI OCT Triton® scans, and three in both devices. Supplemental Table 1 shows the percentual of SS identification in scans by quadrant. Of the remaining 23 subjects, nineteen (83%) were female, and four (17%) were male. The mean age of participants was 65.3 ± 8.1 years, ranging from 49.3 to 80.7 years. The best-corrected visual acuity and the spherical equivalent were 0.15 ± 0.27 and + 0.62 ± 2.54 D, respectively. ACD and AXL were 2.54 ± 0.33 mm and 22.36 ± 0.99 mm, respectively. The mean IOP was 15.22 ± 3.50 mmHg. Eighteen patients (78%) were diagnosed with PAC, and five (22%) with PACG. Gonioscopy presented a better agreement in quadrant closed detection with Visante® OCT (AC1 = 0.52, CI 95% 0.33–0.70) than DRI OCT Triton® (AC1 = 0.12, CI 95% -0.09–0.33). Supplemental Table 2 presents the agreement between techniques separated by quadrants. Agreement between the two OCT devices for categorical angle closure assessment was moderate (AC1 = 0.44; 95% CI: 0.25–0.63). Agreement between the OCT devices in angular and anterior chamber measurements were excellent (ICC = 0.76–0.90). For iris parameters, the agreement was excellent in IAREA (ICC = 0.83), and good for the other iris parameters (ICC = 0.61–0.73). However, there were significant differences in all evaluated parameters by both devices (Table 1 ). All angle-related measurements (AOD250, AOD500, TISA500, and TIA) were higher with the DRI OCT Triton® (Supplemental Fig. 1). In contrast, the iris-related parameters (IT750, IT2000, ICURVE, and IAREA) presented higher values with the Visante® (Supplemental Fig. 2). Table 1 Anterior segment optical tomography quantitative angle parameters measured by Visante ® OCT and DRI Triton ® OCT. Parameter Visante Mean (SD) DRI Triton Mean (SD) p-value Mean Diff. (95% CI) Limits of Agreement ICC AOD250 (mm) 0.07 (0.09) 0.11 (0.09) p < 0.001* -0.03 (-0.05 – -0.02) -0.16–0.09 0.76 (0.66–0.84) AOD500 (mm) 0.10 (0.11) 0.13 (0.12) p < 0.001* -0.04 (-0.05 – -0.02) -0.18–0.10 0.82 (0.74–0.88) TISA500 (mm 2 ) 0.03 (0.04) 0.05 (0.05) p < 0.001* -0.02 (-0.03 – -0.01) -0.08–0.04 0.77 (0.69–0.85) TIA ( o ) 8.84 (10.89) 10.89 (11.09) p = 0.019 -2.05 (-3.40 – -0.70) -14.70–10.60 0.83 (0.76–0.89) IT750 (mm) 0.44 (0.08) 0.40 (0.08) p < 0.001 # 0.04 (0.03–0.06) -0.10–0.18 0.61 (0.46–0.73) IT2000 (mm) 0.46 (0.07) 0.42 (0.08) p < 0.001* 0.05 (0.03–0.06) -0.06–0.15 0.73 (0.61–0.81) ICURVE (mm) 0.29 (0.06) 0.26 (0.08) p < 0.001* 0.03 (0.02–0.04) -0.08–0.14 0.69 (0.57–0.79) IAREA (mm 2 ) 1.66 (0.24) 1.54 (0.24) p < 0.001 # 0.12 (0.09–0.16) -0.16–0.41 0.83 (0.76–0.89) LV (µm) 857.46 (279.38) 310.68 (244.75) p < 0.001 # 546.78 (494.27–599.29) 303.92–789.63 0.89 (0.77–0.95) ACW (mm) 11.42 (0.42) 11.91 (0.43) p < 0.001 # -0.49 (-0.57 – -0.41) -0.87 – -0.11 0.90 (0.78–0.96) PD (mm) 4.07 (0.79) 4.24 (0.97) p = 0.10 -0.17 (-0.38–0.04) -1.12–0.78 0.86 (0.69–0.94) Abbreviations: SD = standard deviation; 95% CI = 95% confidence interval; Diff. = difference; AOD250 = angle opening distance at 250 \(\:{\mu\:}\) m of scleral spur; AOD500 = angle opening distance at 500 \(\:{\mu\:}\) m of scleral spur; TISA500 = trabecular iris space area at 500 \(\:{\mu\:}\) m of scleral spur ; TIA = trabecular iris angle; IT750 = iris thickness at 750 \(\:{\mu\:}\) m of scleral spur; IT2000 = iris thickness at 2000 \(\:{\mu\:}\) m of scleral spur; ICURVE = iris curvature; IAREA = iris area; LV = lens vault; ACW = anterior chamber width; PD = pupillary distance. # Paired t-test * Wilcoxon signed rank test Moreover, the lens vault was significantly higher with the Visante® than with the DRI OCT Triton® (857.46 ± 279.38 µm vs. 310.68 ± 244.75 µm, p < 0.001 – Fig. 2 ). ACW was significantly higher with the DRI OCT Triton® than with the Visante® (11.91 ± 0.43mm vs. 11.42 ± 0.42 mm, p < 0.001). There was no significant difference between PD (4.07 ± 0.79 mm vs. 4.24 ± 0.97mm, p = 0.10) and PD:ACW (0.36 ± 0.07 vs. 0.36 ± 0.08, p = 0.94) measured by Visante® and DRI OCT Triton, respectively. Figure 3 shows a representative scan of each device in the same patient. DISCUSSION AS-OCT is a critical tool in clinical practice, especially in evaluating the angle closure mechanism. Currently, devices such as Visante® OCT, CASIA® (Tomey, Nagoya, Japan), and Anterion® (Heidelberg Engineering, Heidelberg, Germany) are specifically developed for anterior segment analysis. In comparison, other devices as Cirrus® (Carl Zeiss Meditec, Dublin, USA), RTvue® (Optovue, Fremont, USA), The Spectralis® (Heidelberg Engineering, Heidelberg, Germany) and the DRI OCT Triton® are primarily intended for posterior pole assessment but are capable of capturing anterior segment images when used with accessory lens modules. Therefore, it is essential to know if different devices provide representative images with a substantial agreement between quantitative parameters. There are several differences in qualitative information, as well as in quantitative measurements obtained by Visante® and DRI OCT Triton®. We detected a poor to moderate agreement between gonioscopy and AS-OCT, like in previous reports.( 13 – 17 ) This agreement depends on the cohort's anterior chamber characteristics and the technology used to evaluate it. We observed a better agreement of gonioscopy with the Visante® than the DRI OCT Triton®, except at the nasal quadrant, which was absent for both devices. Lune et al. reported a 97.2% agreement in detecting angle closure with the Cirrus 5000® spectral domain OCT, in eyes previously identified as having angle closure by gonioscopy.( 18 ). Desmond et al., in a meta-analysis with the same objective, reported sensitivities above 80% in most studies, while emphasizing the essential role of gonioscopy in the management of angle closure.( 19 ) Yaisiri et al. demonstrated a sensitivity of 92.16% and a specificity of 73.91% for detecting angle closure using the CASIA SS-1000®. Substantial intraobserver and interobserver agreement was observed in the interpretation of AS-OCT images (Kappa = 0.71–0.80 and Kappa = 0.69, respectively).( 20 ) Therefore, the level of agreement depends on both the anterior chamber characteristics of the studied cohort and the imaging technology employed. Agreement between the two OCT devices was moderate (AC1 = 0.44, CI 95%: 0.25–0.63). In a study employing both the spectral-domain Cirrus® and iVue® OCT devices, Quek et al. reported substantial concordance (AC1 = 0.72) in the detection of angle closure.( 15 ) In contrast, Hu et al. observed a poor agreement comparing the Visante® with the Cirrus® OCT.( 13 ) We also evaluated the agreement between the Visante® and the DRI OCT Triton® for quantitative parameters. Most measurements presented a good agreement, with ICC ranging from 0.61–0.90. However, there was a substantial bias between measurements. The DRI OCT Triton® presented higher measurements in angular parameters (AOD250, AOD500, TISA500, and TIA) and ACW. Otherwise, the Visante® presented higher measurements in iris parameters (IT750, IT2000, ICURVE, IAREA) and lens vault. Chansangpetch et al. evaluated the agreement between Visante® and CASIA® and observed a good agreement for all angle parameters. However, Bland-Altman plots demonstrated evidence of a constant bias in AODs between measurements of OCT devices. Among the angular parameters, the CASIA® OCT tended to obtain higher measurements, and the authors recommend that the values acquired with these two devices not to be used interchangeably.( 21 ) In accordance, Angmo et al. related that CASIA100® obtained higher angle parameters measurement than Visante®.( 22 ) In a study comparing the Anterion® and CASIAII® devices, Chan et al. evaluated patients with open-angle glaucoma and primary angle closure and reported low agreement between the two systems. The Anterion® yielded significantly higher values for angular parameters (AOD500 and TISA500), whereas the scleral spur–scleral spur distance (SSD), anterior chamber depth (ACD), and pupil diameter (PD) were significantly lower (p < 0.001).( 23 ) When comparing the CASIA SS-1000® and Anterion® devices in individuals without a diagnosis of glaucoma, Pardeshi et al. found excellent agreement (intraclass correlation coefficient [ICC] range: 0.85–0.96). Linear regression analysis and Bland–Altman plots demonstrated consistency across the full range of measurements. The presence of angle closure may account for the variability observed between devices in previous studies.( 24 ) In our cohort, lens vault was increased by the Visante® (857.46 ± 279.38 µm). Moreover, we observed a significant mean difference between the Visante® and the DRI OCT Triton® (546.78; 95% CI: 494.27–599.29). Lens vault is an important parameter that represents the relationship of the lens with the anterior chamber depth. It evaluates the lens contribution to the angle closure mechanism.( 25 , 26 ) Qualitative evaluation of lens vault presents a critical issue in the analyses of the anterior segment,( 27 ) as this measurement can increase over time and has been associated with narrow angles.( 28 ) Horizontal parameters, such as PD and ACW, were also higher in DRI OCT Triton® images. Both of them were proportionally higher with swept-source OCT, since PD:ACW measurement was similar between devices. Therefore, the DRI OCT Triton® images could impact clinical decisions when based solely on its printouts. The poor agreement and the bias observed, especially in lens vault measurements, could be a consequence of differences in the choice of refractive indexes for calculating anterior segment dimensions. Furthermore, the AS-OCT images are distorted as a result of a shift in light direction at the point of intersection between the air and the cornea., and the measured distances result from optical path length, not the real physical distance.( 29 ) Each AS-OCT device has an inherent algorithm to correct the light direction and physical distance of structures. A discrepancy in the dewarping algorithms of each device could account for the systematic bias observed in our study. There are some limitations in our protocol. We did not have guidelines for describing the image quality of the AS-OCT devices. All AS-OCT scans were evaluated by one grader using ImageJ® software. The SS was manually marked before angle parameter measurements. The AS-OCT grading process was not fully automated, and the identification of SS and tissue borders landmarks could influence the analysis. Furthermore, it cannot be assured that images from both devices were obtained at exactly the same anatomical location. CONCLUSION In conclusion, the Visante® OCT presented a better agreement with gonioscopy than the DRI OCT Triton®. Moreover, a substantial difference between parameters analyzed by AS-OCT devices was observed. CLINICAL SIGNIFICANCE Not only are AS-OCT measurements not interchangeable, but the systematic underestimation of lens vault by the DRI OCT Triton® could potentially lead to misinterpretation of the angle closure mechanism associated with lens enlargement. Declarations The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. The authors have no relevant financial or non-financial interests to disclose. All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by all authors. The first draft of the manuscript was written by Bruno Leonardo Barranco Esporcatte, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the Institutional Ethics Committee of Universidade Federal de São Paulo with number 1685944. Written informed consent for publication was obtained from all patients included in this study. The datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request: Ivan Maynart Tavares, MD ( [email protected] ) References Scheie HG. Width and pigmentation of the angle of the anterior chamber; a system of grading by gonioscopy. AMA Arch Ophthalmol. 1957;58(4):510-2. Shaffer RN. Stereoscopic manual of gonioscopy. Academic Medicine. 1963;38(6):529. Spaeth GL. The normal development of the human anterior chamber angle: a new system of descriptive grading. Trans Ophthalmol Soc U K. 1971;91:709-39. Nongpiur ME, Tun TA, Aung T. Anterior Segment Optical Coherence Tomography: Is There a Clinical Role in the Management of Primary Angle Closure Disease? J Glaucoma. 2020;29(1):60-6. Qin B, Francis BA, Li Y, Tang M, Zhang X, Jiang C, et al. Anterior chamber angle measurements using Schwalbe's line with high-resolution fourier-domain optical coherence tomography. J Glaucoma. 2013;22(9):684-8. Leung CK, Weinreb RN. Anterior chamber angle imaging with optical coherence tomography. Eye (Lond). 2011;25(3):261-7. Fernandez-Vigo JI, Shi H, Kudsieh B, Arriola-Villalobos P, De-Pablo Gomez-de-Liano L, Garcia-Feijoo J, et al. Ciliary muscle dimensions by swept-source optical coherence tomography and correlation study in a large population. Acta Ophthalmol. 2019. Seager FE, Wang J, Arora KS, Quigley HA. The effect of scleral spur identification methods on structural measurements by anterior segment optical coherence tomography. J Glaucoma. 2014;23(1):e29-38. Chansangpetch S, Rojanapongpun P, Lin SC. Anterior Segment Imaging for Angle Closure. Am J Ophthalmol. 2018;188:xvi-xxix. Gwet KL. Computing inter-rater reliability and its variance in the presence of high agreement. Br J Math Stat Psychol. 2008;61(Pt 1):29-48. Landis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74. Cicchetti DV. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychological assessment. 1994;6(4):284. Hu CX, Mantravadi A, Zangalli C, Ali M, Faria BM, Richman J, et al. Comparing Gonioscopy With Visante and Cirrus Optical Coherence Tomography for Anterior Chamber Angle Assessment in Glaucoma Patients. J Glaucoma. 2016;25(2):177-83. Park SB, Sung KR, Kang SY, Jo JW, Lee KS, Kook MS. Assessment of narrow angles by gonioscopy, Van Herick method and anterior segment optical coherence tomography. Jpn J Ophthalmol. 2011;55(4):343-50. Quek DT, Narayanaswamy AK, Tun TA, Htoon HM, Baskaran M, Perera SA, et al. Comparison of two spectral domain optical coherence tomography devices for angle-closure assessment. Invest Ophthalmol Vis Sci. 2012;53(9):5131-6. Rigi M, Bell NP, Lee DA, Baker LA, Chuang AZ, Nguyen D, et al. Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging. J Ophthalmol. 2016;2016:1727039. Jaseena K, Rekha PS. Agreement of gonioscopy and anterior segment-optical coherence tomography in the assessment of the anterior chamber angle: A cross-sectional study. Kerala Journal of Ophthalmology. 2022;34(1). Lune A, Prabhudesai A. A Comparative Study of Anterior Segment Optical Coherence Tomography and Gonioscopy in Detection of Narrow, Occludable Angles. Cureus. 2024;16(9):e69879. Desmond T, Tran V, Maharaj M, Carnt N, White A. Diagnostic accuracy of AS-OCT vs gonioscopy for detecting angle closure: a systematic review and meta-analysis. Graefes Arch Clin Exp Ophthalmol. 2022;260(1):1-23. Yaisiri P, Panarojwongse N, Treesit I, Choontanom R, Jatuthong O, Iemsomboon W, et al. Comparison of Swept-Source Anterior Segment Ocular Coherence Tomography and Gonioscopy in Detecting Anterior Chamber Angle Closure. Clin Ophthalmol. 2025;19:699-711. Chansangpetch S, Nguyen A, Mora M, Badr M, He M, Porco TC, et al. Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography. Invest Ophthalmol Vis Sci. 2018;59(3):1554-61. Angmo D, Singh R, Chaurasia S, Yadav S, Dada T. Evaluation of anterior segment parameters with two anterior segment optical coherence tomography systems: Visante and Casia, in primary angle closure disease. Indian J Ophthalmol. 2019;67(4):500-4. Chan PP, Lai G, Chiu V, Chong A, Yu M, Leung CK. Anterior chamber angle imaging with swept-source optical coherence tomography: comparison between CASIAII and ANTERION. Sci Rep. 2020;10(1):18771. Pardeshi AA, Song AE, Lazkani N, Xie X, Huang A, Xu BY. Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices. Transl Vis Sci Technol. 2020;9(9):14. Wang YE, Li Y, Wang D, He M, Lin S. Comparison of factors associated with occludable angle between american Caucasians and ethnic Chinese. Invest Ophthalmol Vis Sci. 2013;54(12):7717-23. Ozaki M, Nongpiur ME, Aung T, He M, Mizoguchi T. Increased lens vault as a risk factor for angle closure: confirmation in a Japanese population. Graefes Arch Clin Exp Ophthalmol. 2012;250(12):1863-8. Moghimi S, Chen R, Hamzeh N, Khatibi N, Lin SC. Qualitative evaluation of anterior segment in angle closure disease using anterior segment optical coherence tomography. J Curr Ophthalmol. 2016;28(4):170-5. Kwon J, Sung KR, Han S. Long-term Changes in Anterior Segment Characteristics of Eyes With Different Primary Angle-Closure Mechanisms. Am J Ophthalmol. 2018;191:54-63. Tian J, Marziliano P, Baskaran M, Wong HT, Aung T. Automatic anterior chamber angle assessment for HD-OCT images. IEEE Trans Biomed Eng. 2011;58(11):3242-9. Additional Declarations No competing interests reported. Supplementary Files SupplementalTable1.docx SupplementalTable2.docx SupplementalFig1.docx SupplementalFig2.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8752901","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":584650496,"identity":"02d0a73f-9253-4b9a-a10b-82377121132a","order_by":0,"name":"Bruno Leonardo Barranco Esporcatte","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Bruno","middleName":"Leonardo Barranco","lastName":"Esporcatte","suffix":""},{"id":584650497,"identity":"10983c57-540f-444b-bac2-2292cc7eb992","order_by":1,"name":"Arthur Franco Brun","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Arthur","middleName":"Franco","lastName":"Brun","suffix":""},{"id":584650499,"identity":"b10ea464-c358-4533-8ea9-025d6aa777a4","order_by":2,"name":"Norton Sakassegawa Yanagimori","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Norton","middleName":"Sakassegawa","lastName":"Yanagimori","suffix":""},{"id":584650502,"identity":"22e2ec4c-a08b-42c2-a279-2bdc9699fff5","order_by":3,"name":"Luiz Alberto Soares de Melo Junior","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Luiz","middleName":"Alberto Soares de Melo","lastName":"Junior","suffix":""},{"id":584650505,"identity":"ec71440d-241a-4a8e-9f58-f4f174fe699f","order_by":4,"name":"Roberto Murad Vessani","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Roberto","middleName":"Murad","lastName":"Vessani","suffix":""},{"id":584650509,"identity":"490e8613-7fab-4f0b-813c-405d7ea932a2","order_by":5,"name":"Guilherme Havir Bufarah","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Guilherme","middleName":"Havir","lastName":"Bufarah","suffix":""},{"id":584650511,"identity":"f2916529-f78f-48e9-868b-0d5fac134106","order_by":6,"name":"Norma Allemann","email":"","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":false,"prefix":"","firstName":"Norma","middleName":"","lastName":"Allemann","suffix":""},{"id":584650514,"identity":"1771b2d9-d076-4558-a607-854ddb3f8f89","order_by":7,"name":"Ivan Maynart Tavares","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5ElEQVRIiWNgGAWjYBACNgST+QADg4EcmiB2LYwNUGYCUIsxYS0MCC08BkCCCC18YgfYH/xss8vn5z/zTbqgwEBOfnYD2+MKfA6TTmBs7G1Ltpw5I3eb9AwDA2ODOwfYDc8Q0NLAc4bZwOAG7zZpHoM/iRskEtgkGwjZ8udMvYH9+TPPgFoM6ufPIEJLM0/FYQMDhhw2kJYEhhsEtSQ2zpapOG4gcSPN2BqoxXDDnYPthvi0yM9OPvDxjUG1AX//4Ye3ef4YyMvPbj72EJ8WRLTAgQSGCEEgQaqGUTAKRsEoGO4AAOwSQ5SiMyJmAAAAAElFTkSuQmCC","orcid":"","institution":"Federal University of Sao Paulo","correspondingAuthor":true,"prefix":"","firstName":"Ivan","middleName":"Maynart","lastName":"Tavares","suffix":""}],"badges":[],"createdAt":"2026-01-31 23:53:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8752901/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8752901/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101944638,"identity":"4869b824-baa7-4c10-a729-f909cfd3d9a7","added_by":"auto","created_at":"2026-02-05 09:53:18","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2597347,"visible":true,"origin":"","legend":"\u003cp\u003eExample images obtained with anterior segment OCT showing the parameters evaluated. Angular parameters: angle opening distance at 250 μm, 500 μm from the scleral spur (AOD250, AOD500), trabecular-iris angle (TIA), and trabecular-iris space area at 500 μm (TISA500). Iris parameters: iris thickness at 750 mm (IT750) and 2000 mm (IT2000) from the SS, iris curvature (ICURVE) and iris area in the cross-sectional area of the full length of the iris (IAREA). Anterior chamber parameters: dashed line represents the anterior-chamber width (ACW), solid line represents the lens vault (LV), and solid line with arrowheads represents the pupillary distance (PD)\u003c/p\u003e","description":"","filename":"Fig1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/0e62eb0dfc9a0fa0662b49a3.jpg"},{"id":101944656,"identity":"d9064198-8ac1-470f-9c96-985b1dbaad97","added_by":"auto","created_at":"2026-02-05 09:53:30","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":226898,"visible":true,"origin":"","legend":"\u003cp\u003eBland–Altman plot for the lens vault (LV) and anterior-chamber width (ACW) parameters. Graph A shows the LV measurements, while Graph B shows the ACW measurements\u003c/p\u003e\n\u003cp\u003eNote: The data were plotted according to the difference between the measurements obtained by the two devices (y-axis: Visante\u003csup\u003e®\u003c/sup\u003e OCT – DRI OCT Triton\u003csup\u003e®\u003c/sup\u003e) and the mean of the values obtained (x-axis). The solid line represents the mean difference between measurements, and the dashed lines represent the limits of agreement.\u003c/p\u003e","description":"","filename":"Fig2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/1b997de82dd51b8ed6d78121.jpg"},{"id":101945108,"identity":"f72ad22c-7082-4832-a93b-becf2dd59635","added_by":"auto","created_at":"2026-02-05 09:55:25","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":488586,"visible":true,"origin":"","legend":"\u003cp\u003eLens vault images obtained with AS-OCT devices. Solid line represents the lens vault (LV). Superior: Visante\u003csup\u003e®\u003c/sup\u003e OCT. Inferior: DRI OCT Triton\u003csup\u003e®\u003c/sup\u003e.\u003cbr\u003e\nNote: A difference in LV measurements between the two devices can be observed\u003c/p\u003e","description":"","filename":"Fig3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/13b7c5063178e6d065d89be5.jpg"},{"id":105035868,"identity":"29fab2c1-2e45-4fca-a860-9ba6e3ae37ad","added_by":"auto","created_at":"2026-03-20 07:26:48","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3887990,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/772ad540-1e38-4e9f-b1b0-fb360c0b356a.pdf"},{"id":101946286,"identity":"f336fed1-b901-4ded-8e53-c8b48d2ee0d0","added_by":"auto","created_at":"2026-02-05 10:01:03","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":16581,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalTable1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/0883b2e70b6a901be48e4637.docx"},{"id":101944160,"identity":"f31169ce-d094-4a2e-82f3-c654d943e969","added_by":"auto","created_at":"2026-02-05 09:49:21","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":16035,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalTable2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/f880e2481074f2af278f2095.docx"},{"id":101945109,"identity":"128d1d41-215e-4da3-b060-397a4d8f2020","added_by":"auto","created_at":"2026-02-05 09:55:25","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":138747,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalFig1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/9d18fe0c3af61badda33172e.docx"},{"id":101945123,"identity":"db98a387-850f-4b23-9344-33a51c0cab75","added_by":"auto","created_at":"2026-02-05 09:55:27","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":144909,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalFig2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8752901/v1/4f24b01aba77f2762fc79e82.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Disagreement between anterior segment optical coherence tomography devices in eyes with a shallow anterior chamber","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eThe anterior chamber anatomy was clinically evaluated using slit-lamp biomicroscopy and gonioscopy. However, gonioscopy is a time-consuming examination, is associated with substantial patient discomfort, and its grading may vary among clinicians. Moreover, it is difficult to document the test results, and there are several classifications of gonioscopic findings, which may confuse physicians.(\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eAnterior segment optical coherence tomography (AS-OCT) offers detailed real-time imaging of the anterior segment with high resolution. The method is frequently employed because it is contactless, rapid, semi-automatic, requires little operator involvement, and demonstrates consistent reproducibility.(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eThe Visante\u0026reg; OCT (Carl Zeiss Meditec, Dublin, USA) is a time-domain OCT device, introduced in 2006, specifically designed for anterior segment imaging.(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e) The DRI OCT Triton\u0026reg; (Topcon Corporation, Tokyo, Japan) is a swept-source OCT system introduced in 2015 for retinal imaging. With the optional anterior segment lens, it can produce B-scans up to 16 mm in length, enabling simultaneous visualization of opposite angles along the same axis.(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eTo date, no study in the literature compares the angular or anterior chamber measurements obtained with these devices. Therefore, the objective of this study was to assess the level of agreement between measurements obtained with the Visante\u0026reg; and the DRI OCT Triton\u0026reg; in eyes with shallow anterior chambers, as well as to evaluate potential discrepancies between the values obtained from both devices.\u003c/p\u003e"},{"header":"MATERIALS \u0026 METHODS","content":"\u003cp\u003e The Institutional Ethics Committee authorized the protocol, and all subjects provided written informed permission before being included in the study. The study was structured as an observational, cross-sectional design aimed at analyzing data obtained with two different types of AS-OCT devices.\u003c/p\u003e \u003cp\u003eAll participants were initially evaluated by a complete ophthalmological exam, including best-corrected visual acuity with manifest refraction, biomicroscopy, intraocular pressure measurement (IOP - Goldmann tonometry), and non-mydriatic fundoscopic evaluation. In addition, measurements of anterior chamber depth (ACD) and axial length (AXL) were obtained using the IOL Master\u0026reg; 500 (Carl Zeiss Meditec, Dublin, CA, USA). To minimize measurement bias, all images were acquired by a single examiner who was masked to the results of the other device, and gonioscopy was performed by a glaucoma specialist.\u003c/p\u003e \u003cp\u003eAll participants were attended at the glaucoma department for an evaluation of angle status and to validate laser peripheral iridotomy indication. Only subjects presenting a peripheral ACD to peripheral corneal thickness (PACD:PCT) ratio of less than 1/2 were enrolled in the study. Subjects with previous intraocular surgery, laser procedures (iridotomy or iridoplasty), or ocular trauma history were excluded.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eGonioscopy\u003c/h2\u003e \u003cp\u003eIn this protocol, only the initial eye under examination was included. Glaucoma experts performed the gonioscopy before AS-OCT evaluation.\u003c/p\u003e \u003cp\u003eEach participant underwent gonioscopy with a Sussman four-mirror lens (Ocular Inst., Bellevue, USA). Examinations were conducted in dark conditions while maintaining the eye in primary gaze. A minimal light beam was applied to inspect the angle under high magnification, avoiding direct illumination of the pupil. The visibility of anatomical landmarks\u0026mdash;such as Schwalbe\u0026rsquo;s line, anterior (non-pigmented) trabecular meshwork, posterior (pigmented) trabecular meshwork, scleral spur, and ciliary body band\u0026mdash;was recorded during static gonioscopy. Indentation was subsequently performed to verify the presence of synechiae, imprints, or both.\u003c/p\u003e \u003cp\u003eA quadrant was considered closed on gonioscopy when the pigmented trabecular meshwork was not visible during static evaluation. Patients were diagnosed with primary angle closure (PAC) if at least two quadrants were closed and either synechiae or appositional contact were present. Primary angle closure glaucoma was defined as the coexistence of PAC gonioscopic findings with glaucomatous optic neuropathy, characterized by localized or diffuse neuroretinal rim loss or retinal nerve fiber layer thinning on fundus examination.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eAS-OCT\u003c/h3\u003e\n\u003cp\u003eAnterior segment images were captured using a time-domain Visante\u0026reg; OCT and a swept-source DRI OCT Triton\u0026reg;, both performed under dark conditions (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Each image was centered on the pupil and acquired along the horizontal meridian (from 3 to 9 o\u0026rsquo;clock) as well as the vertical meridian (from 12 to 6 o\u0026rsquo;clock). If necessary, upper or lower eyelids were gently displaced during image capture.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA masked examiner analyzed all AS-OCT images using ImageJ\u0026reg; software (V.1.50i). Only scans correctly centered and with discernible scleral spur (SS) were analyzed. The determination of SS was based on previously described criteria.(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) All quantitative variables were measured after manually marking SS. The following parameters were assessed to compare the two OCT devices: angle opening distance at 250 \u0026micro;m and 500 \u0026micro;m from the SS (AOD250, AOD500), trabecular-iris space at 500 \u0026micro;m from the SS (TISA500), and trabecular-iris angle (TIA). The iris parameters measured were iris thickness at 750 \u0026micro;m (IT750) and 2000 \u0026micro;m (IT2000) from the SS, iris curvature (ICURVE), and iris area in the cross-sectional area of the full length of the iris (IAREA). The anterior chamber parameters evaluated were: lens vault, pupillary distance (PD), and anterior chamber width (ACW). The definitions of each parameter have been previously described.(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) The ratio between PD and ACW (PD:ACW) was also calculated.\u003c/p\u003e \u003cp\u003eA quadrant was classified as closed on AS-OCT when contact was observed between the iris and the corneoscleral surface located anterior to the scleral spur.\u003c/p\u003e\n\u003ch3\u003eStatistics\u003c/h3\u003e\n\u003cp\u003eStatistical analyses were conducted using Stata\u0026reg; software (version 15; StataCorp, College Station, USA). The McNemar test evaluated differences in the distribution of categorical variables. Depending on variable distribution, either a paired t-test or a Wilcoxon signed-rank test was applied.\u003c/p\u003e \u003cp\u003eThe first-order agreement coefficient (AC1) was applied to measure concordance among categorical variables. AC1 statistics were also employed to determine the level of agreement between the tests.(\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e) Qualitative ratings of agreement statistics were used based on Landis and Koch.(\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e) Intraclass correlation coefficient (ICC) and Bland-Altman plots were used to assess the agreement between quantitative parameters obtained by the devices.(\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eGiven the exploratory nature of the study and a sample size close to 20 subjects, Bland\u0026ndash;Altman analysis was applied for descriptive assessment of agreement. The sample size was considered sufficient to allow an approximate normal distribution of the differences, which was evaluated prior to analysis.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003eInitially, 44 eyes were included, and 21 eyes were excluded from the study due to unclear identification of SS in at least one quadrant of any AS-OCT. Six eyes presented a poor-quality image in Visante\u0026reg; OCT scans, twelve in DRI OCT Triton\u0026reg; scans, and three in both devices. Supplemental Table\u0026nbsp;1 shows the percentual of SS identification in scans by quadrant.\u003c/p\u003e \u003cp\u003eOf the remaining 23 subjects, nineteen (83%) were female, and four (17%) were male. The mean age of participants was 65.3 \u0026plusmn; 8.1 years, ranging from 49.3 to 80.7 years. The best-corrected visual acuity and the spherical equivalent were 0.15 \u0026plusmn; 0.27 and +\u0026thinsp;0.62 \u0026plusmn; 2.54 D, respectively. ACD and AXL were 2.54 \u0026plusmn; 0.33 mm and 22.36 \u0026plusmn; 0.99 mm, respectively. The mean IOP was 15.22 \u0026plusmn; 3.50 mmHg. Eighteen patients (78%) were diagnosed with PAC, and five (22%) with PACG.\u003c/p\u003e \u003cp\u003eGonioscopy presented a better agreement in quadrant closed detection with Visante\u0026reg; OCT (AC1\u0026thinsp;=\u0026thinsp;0.52, CI 95% 0.33\u0026ndash;0.70) than DRI OCT Triton\u0026reg; (AC1\u0026thinsp;=\u0026thinsp;0.12, CI 95% -0.09\u0026ndash;0.33). Supplemental Table\u0026nbsp;2 presents the agreement between techniques separated by quadrants.\u003c/p\u003e \u003cp\u003e Agreement between the two OCT devices for categorical angle closure assessment was moderate (AC1\u0026thinsp;=\u0026thinsp;0.44; 95% CI: 0.25\u0026ndash;0.63). Agreement between the OCT devices in angular and anterior chamber measurements were excellent (ICC\u0026thinsp;=\u0026thinsp;0.76\u0026ndash;0.90). For iris parameters, the agreement was excellent in IAREA (ICC\u0026thinsp;=\u0026thinsp;0.83), and good for the other iris parameters (ICC\u0026thinsp;=\u0026thinsp;0.61\u0026ndash;0.73). However, there were significant differences in all evaluated parameters by both devices (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). All angle-related measurements (AOD250, AOD500, TISA500, and TIA) were higher with the DRI OCT Triton\u0026reg; (Supplemental Fig.\u0026nbsp;1). In contrast, the iris-related parameters (IT750, IT2000, ICURVE, and IAREA) presented higher values with the Visante\u0026reg; (Supplemental Fig.\u0026nbsp;2).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAnterior segment optical tomography quantitative angle parameters measured by Visante\u003csup\u003e\u0026reg;\u003c/sup\u003e OCT and DRI Triton\u003csup\u003e\u0026reg;\u003c/sup\u003e OCT.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eVisante Mean\u003c/p\u003e \u003cp\u003e(SD)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDRI Triton\u003c/p\u003e \u003cp\u003eMean\u003c/p\u003e \u003cp\u003e(SD)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep-value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eMean Diff.\u003c/p\u003e \u003cp\u003e(95% CI)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eLimits of Agreement\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eICC\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAOD250 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.07\u003c/p\u003e \u003cp\u003e(0.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003cp\u003e(0.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.03\u003c/p\u003e \u003cp\u003e(-0.05 \u0026ndash; -0.02)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.16\u0026ndash;0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.76\u003c/p\u003e \u003cp\u003e(0.66\u0026ndash;0.84)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAOD500 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.10\u003c/p\u003e \u003cp\u003e(0.11)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003cp\u003e(0.12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.04\u003c/p\u003e \u003cp\u003e(-0.05 \u0026ndash; -0.02)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.18\u0026ndash;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.82\u003c/p\u003e \u003cp\u003e(0.74\u0026ndash;0.88)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTISA500 (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003cp\u003e(0.04)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003cp\u003e(0.05)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.02\u003c/p\u003e \u003cp\u003e(-0.03 \u0026ndash; -0.01)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.08\u0026ndash;0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.77\u003c/p\u003e \u003cp\u003e(0.69\u0026ndash;0.85)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA (\u003csup\u003eo\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.84\u003c/p\u003e \u003cp\u003e(10.89)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.89\u003c/p\u003e \u003cp\u003e(11.09)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-2.05\u003c/p\u003e \u003cp\u003e(-3.40 \u0026ndash; -0.70)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-14.70\u0026ndash;10.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003cp\u003e(0.76\u0026ndash;0.89)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIT750 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.44\u003c/p\u003e \u003cp\u003e(0.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.40\u003c/p\u003e \u003cp\u003e(0.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003cp\u003e(0.03\u0026ndash;0.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.10\u0026ndash;0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.61\u003c/p\u003e \u003cp\u003e(0.46\u0026ndash;0.73)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIT2000 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.46\u003c/p\u003e \u003cp\u003e(0.07)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.42\u003c/p\u003e \u003cp\u003e(0.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003cp\u003e(0.03\u0026ndash;0.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.06\u0026ndash;0.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.73\u003c/p\u003e \u003cp\u003e(0.61\u0026ndash;0.81)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICURVE (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.29\u003c/p\u003e \u003cp\u003e(0.06)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.26\u003c/p\u003e \u003cp\u003e(0.08)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.03\u003c/p\u003e \u003cp\u003e(0.02\u0026ndash;0.04)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.08\u0026ndash;0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.69\u003c/p\u003e \u003cp\u003e(0.57\u0026ndash;0.79)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIAREA (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.66\u003c/p\u003e \u003cp\u003e(0.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.54\u003c/p\u003e \u003cp\u003e(0.24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003cp\u003e(0.09\u0026ndash;0.16)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.16\u0026ndash;0.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003cp\u003e(0.76\u0026ndash;0.89)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLV (\u0026micro;m)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e857.46\u003c/p\u003e \u003cp\u003e(279.38)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e310.68\u003c/p\u003e \u003cp\u003e(244.75)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e546.78\u003c/p\u003e \u003cp\u003e(494.27\u0026ndash;599.29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e303.92\u0026ndash;789.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.89\u003c/p\u003e \u003cp\u003e(0.77\u0026ndash;0.95)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eACW (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.42\u003c/p\u003e \u003cp\u003e(0.42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.91\u003c/p\u003e \u003cp\u003e(0.43)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003csup\u003e#\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.49\u003c/p\u003e \u003cp\u003e(-0.57 \u0026ndash; -0.41)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-0.87 \u0026ndash; -0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.90\u003c/p\u003e \u003cp\u003e(0.78\u0026ndash;0.96)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePD (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.07\u003c/p\u003e \u003cp\u003e(0.79)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.24\u003c/p\u003e \u003cp\u003e(0.97)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-0.17\u003c/p\u003e \u003cp\u003e(-0.38\u0026ndash;0.04)\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e-1.12\u0026ndash;0.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.86\u003c/p\u003e \u003cp\u003e(0.69\u0026ndash;0.94)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"7\"\u003eAbbreviations: SD\u0026thinsp;=\u0026thinsp;standard deviation; 95% CI\u0026thinsp;=\u0026thinsp;95% confidence interval; Diff. = difference; AOD250\u0026thinsp;=\u0026thinsp;angle opening distance at 250 \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mu\\:}\\)\u003c/span\u003e\u003c/span\u003em of scleral spur; AOD500\u0026thinsp;=\u0026thinsp;angle opening distance at 500 \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mu\\:}\\)\u003c/span\u003e\u003c/span\u003em of scleral spur; TISA500\u0026thinsp;=\u0026thinsp;trabecular iris space area at 500\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mu\\:}\\)\u003c/span\u003e\u003c/span\u003em of scleral spur ; TIA\u0026thinsp;=\u0026thinsp;trabecular iris angle; IT750\u0026thinsp;=\u0026thinsp;iris thickness at 750 \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mu\\:}\\)\u003c/span\u003e\u003c/span\u003em of scleral spur; IT2000\u0026thinsp;=\u0026thinsp;iris thickness at 2000\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{\\mu\\:}\\)\u003c/span\u003e\u003c/span\u003em of scleral spur; ICURVE\u0026thinsp;=\u0026thinsp;iris curvature; IAREA\u0026thinsp;=\u0026thinsp;iris area; LV\u0026thinsp;=\u0026thinsp;lens vault; ACW\u0026thinsp;=\u0026thinsp;anterior chamber width; PD\u0026thinsp;=\u0026thinsp;pupillary distance. # Paired t-test * Wilcoxon signed rank test\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eMoreover, the lens vault was significantly higher with the Visante\u0026reg; than with the DRI OCT Triton\u0026reg; (857.46 \u0026plusmn; 279.38 \u0026micro;m vs. 310.68 \u0026plusmn; 244.75 \u0026micro;m, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 \u0026ndash; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). ACW was significantly higher with the DRI OCT Triton\u0026reg; than with the Visante\u0026reg; (11.91 \u0026plusmn; 0.43mm vs. 11.42 \u0026plusmn; 0.42 mm, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). There was no significant difference between PD (4.07 \u0026plusmn; 0.79 mm vs. 4.24 \u0026plusmn; 0.97mm, p\u0026thinsp;=\u0026thinsp;0.10) and PD:ACW (0.36 \u0026plusmn; 0.07 vs. 0.36 \u0026plusmn; 0.08, p\u0026thinsp;=\u0026thinsp;0.94) measured by Visante\u0026reg; and DRI OCT Triton, respectively. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows a representative scan of each device in the same patient.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eAS-OCT is a critical tool in clinical practice, especially in evaluating the angle closure mechanism. Currently, devices such as Visante\u0026reg; OCT, CASIA\u0026reg; (Tomey, Nagoya, Japan), and Anterion\u0026reg; (Heidelberg Engineering, Heidelberg, Germany) are specifically developed for anterior segment analysis. In comparison, other devices as Cirrus\u0026reg; (Carl Zeiss Meditec, Dublin, USA), RTvue\u0026reg; (Optovue, Fremont, USA), The Spectralis\u0026reg; (Heidelberg Engineering, Heidelberg, Germany) and the DRI OCT Triton\u0026reg; are primarily intended for posterior pole assessment but are capable of capturing anterior segment images when used with accessory lens modules. Therefore, it is essential to know if different devices provide representative images with a substantial agreement between quantitative parameters. There are several differences in qualitative information, as well as in quantitative measurements obtained by Visante\u0026reg; and DRI OCT Triton\u0026reg;.\u003c/p\u003e \u003cp\u003eWe detected a poor to moderate agreement between gonioscopy and AS-OCT, like in previous reports.(\u003cspan additionalcitationids=\"CR14 CR15 CR16\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e) This agreement depends on the cohort's anterior chamber characteristics and the technology used to evaluate it. We observed a better agreement of gonioscopy with the Visante\u0026reg; than the DRI OCT Triton\u0026reg;, except at the nasal quadrant, which was absent for both devices. Lune et al. reported a 97.2% agreement in detecting angle closure with the Cirrus 5000\u0026reg; spectral domain OCT, in eyes previously identified as having angle closure by gonioscopy.(\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e). Desmond et al., in a meta-analysis with the same objective, reported sensitivities above 80% in most studies, while emphasizing the essential role of gonioscopy in the management of angle closure.(\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e) Yaisiri et al. demonstrated a sensitivity of 92.16% and a specificity of 73.91% for detecting angle closure using the CASIA SS-1000\u0026reg;. Substantial intraobserver and interobserver agreement was observed in the interpretation of AS-OCT images (Kappa\u0026thinsp;=\u0026thinsp;0.71\u0026ndash;0.80 and Kappa\u0026thinsp;=\u0026thinsp;0.69, respectively).(\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) Therefore, the level of agreement depends on both the anterior chamber characteristics of the studied cohort and the imaging technology employed.\u003c/p\u003e \u003cp\u003eAgreement between the two OCT devices was moderate (AC1\u0026thinsp;=\u0026thinsp;0.44, CI 95%: 0.25\u0026ndash;0.63). In a study employing both the spectral-domain Cirrus\u0026reg; and iVue\u0026reg; OCT devices, Quek et al. reported substantial concordance (AC1\u0026thinsp;=\u0026thinsp;0.72) in the detection of angle closure.(\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) In contrast, Hu et al. observed a poor agreement comparing the Visante\u0026reg; with the Cirrus\u0026reg; OCT.(\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eWe also evaluated the agreement between the Visante\u0026reg; and the DRI OCT Triton\u0026reg; for quantitative parameters. Most measurements presented a good agreement, with ICC ranging from 0.61\u0026ndash;0.90. However, there was a substantial bias between measurements. The DRI OCT Triton\u0026reg; presented higher measurements in angular parameters (AOD250, AOD500, TISA500, and TIA) and ACW. Otherwise, the Visante\u0026reg; presented higher measurements in iris parameters (IT750, IT2000, ICURVE, IAREA) and lens vault. Chansangpetch et al. evaluated the agreement between Visante\u0026reg; and CASIA\u0026reg; and observed a good agreement for all angle parameters. However, Bland-Altman plots demonstrated evidence of a constant bias in AODs between measurements of OCT devices. Among the angular parameters, the CASIA\u0026reg; OCT tended to obtain higher measurements, and the authors recommend that the values acquired with these two devices not to be used interchangeably.(\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e) In accordance, Angmo et al. related that CASIA100\u0026reg; obtained higher angle parameters measurement than Visante\u0026reg;.(\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e) In a study comparing the Anterion\u0026reg; and CASIAII\u0026reg; devices, Chan et al. evaluated patients with open-angle glaucoma and primary angle closure and reported low agreement between the two systems. The Anterion\u0026reg; yielded significantly higher values for angular parameters (AOD500 and TISA500), whereas the scleral spur\u0026ndash;scleral spur distance (SSD), anterior chamber depth (ACD), and pupil diameter (PD) were significantly lower (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).(\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e) When comparing the CASIA SS-1000\u0026reg; and Anterion\u0026reg; devices in individuals without a diagnosis of glaucoma, Pardeshi et al. found excellent agreement (intraclass correlation coefficient [ICC] range: 0.85\u0026ndash;0.96). Linear regression analysis and Bland\u0026ndash;Altman plots demonstrated consistency across the full range of measurements. The presence of angle closure may account for the variability observed between devices in previous studies.(\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eIn our cohort, lens vault was increased by the Visante\u0026reg; (857.46 \u0026plusmn; 279.38 \u0026micro;m). Moreover, we observed a significant mean difference between the Visante\u0026reg; and the DRI OCT Triton\u0026reg; (546.78; 95% CI: 494.27\u0026ndash;599.29). Lens vault is an important parameter that represents the relationship of the lens with the anterior chamber depth. It evaluates the lens contribution to the angle closure mechanism.(\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e) Qualitative evaluation of lens vault presents a critical issue in the analyses of the anterior segment,(\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e) as this measurement can increase over time and has been associated with narrow angles.(\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eHorizontal parameters, such as PD and ACW, were also higher in DRI OCT Triton\u0026reg; images. Both of them were proportionally higher with swept-source OCT, since PD:ACW measurement was similar between devices. Therefore, the DRI OCT Triton\u0026reg; images could impact clinical decisions when based solely on its printouts. The poor agreement and the bias observed, especially in lens vault measurements, could be a consequence of differences in the choice of refractive indexes for calculating anterior segment dimensions. Furthermore, the AS-OCT images are distorted as a result of a shift in light direction at the point of intersection between the air and the cornea., and the measured distances result from optical path length, not the real physical distance.(\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e) Each AS-OCT device has an inherent algorithm to correct the light direction and physical distance of structures. A discrepancy in the dewarping algorithms of each device could account for the systematic bias observed in our study.\u003c/p\u003e \u003cp\u003eThere are some limitations in our protocol. We did not have guidelines for describing the image quality of the AS-OCT devices. All AS-OCT scans were evaluated by one grader using ImageJ\u0026reg; software. The SS was manually marked before angle parameter measurements. The AS-OCT grading process was not fully automated, and the identification of SS and tissue borders landmarks could influence the analysis. Furthermore, it cannot be assured that images from both devices were obtained at exactly the same anatomical location.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eIn conclusion, the Visante\u0026reg; OCT presented a better agreement with gonioscopy than the DRI OCT Triton\u0026reg;. Moreover, a substantial difference between parameters analyzed by AS-OCT devices was observed.\u003c/p\u003e"},{"header":"CLINICAL SIGNIFICANCE","content":"\u003cp\u003eNot only are AS-OCT measurements not interchangeable, but the systematic underestimation of lens vault by the DRI OCT Triton\u0026reg; could potentially lead to misinterpretation of the angle closure mechanism associated with lens enlargement.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors have no relevant financial or non-financial interests to disclose.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by all authors. The first draft of the manuscript was written by Bruno Leonardo Barranco Esporcatte, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by\u0026nbsp;the Institutional Ethics Committee of Universidade Federal de S\u0026atilde;o Paulo with number 1685944.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWritten informed consent for publication was obtained from all patients included in this study.\u003c/p\u003e\n\u003cp\u003eThe datasets generated and/or analyzed during the current study are available from the corresponding author upon reasonable request: Ivan Maynart Tavares, MD ([email protected])\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eScheie HG. Width and pigmentation of the angle of the anterior chamber; a system of grading by gonioscopy. AMA Arch Ophthalmol. 1957;58(4):510-2.\u003c/li\u003e\n\u003cli\u003eShaffer RN. Stereoscopic manual of gonioscopy. Academic Medicine. 1963;38(6):529.\u003c/li\u003e\n\u003cli\u003eSpaeth GL. The normal development of the human anterior chamber angle: a new system of descriptive grading. Trans Ophthalmol Soc U K. 1971;91:709-39.\u003c/li\u003e\n\u003cli\u003eNongpiur ME, Tun TA, Aung T. Anterior Segment Optical Coherence Tomography: Is There a Clinical Role in the Management of Primary Angle Closure Disease? J Glaucoma. 2020;29(1):60-6.\u003c/li\u003e\n\u003cli\u003eQin B, Francis BA, Li Y, Tang M, Zhang X, Jiang C, et al. Anterior chamber angle measurements using Schwalbe\u0026apos;s line with high-resolution fourier-domain optical coherence tomography. J Glaucoma. 2013;22(9):684-8.\u003c/li\u003e\n\u003cli\u003eLeung CK, Weinreb RN. Anterior chamber angle imaging with optical coherence tomography. Eye (Lond). 2011;25(3):261-7.\u003c/li\u003e\n\u003cli\u003eFernandez-Vigo JI, Shi H, Kudsieh B, Arriola-Villalobos P, De-Pablo Gomez-de-Liano L, Garcia-Feijoo J, et al. Ciliary muscle dimensions by swept-source optical coherence tomography and correlation study in a large population. Acta Ophthalmol. 2019.\u003c/li\u003e\n\u003cli\u003eSeager FE, Wang J, Arora KS, Quigley HA. The effect of scleral spur identification methods on structural measurements by anterior segment optical coherence tomography. J Glaucoma. 2014;23(1):e29-38.\u003c/li\u003e\n\u003cli\u003eChansangpetch S, Rojanapongpun P, Lin SC. Anterior Segment Imaging for Angle Closure. Am J Ophthalmol. 2018;188:xvi-xxix.\u003c/li\u003e\n\u003cli\u003eGwet KL. Computing inter-rater reliability and its variance in the presence of high agreement. Br J Math Stat Psychol. 2008;61(Pt 1):29-48.\u003c/li\u003e\n\u003cli\u003eLandis JR, Koch GG. The measurement of observer agreement for categorical data. Biometrics. 1977;33(1):159-74.\u003c/li\u003e\n\u003cli\u003eCicchetti DV. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychological assessment. 1994;6(4):284.\u003c/li\u003e\n\u003cli\u003eHu CX, Mantravadi A, Zangalli C, Ali M, Faria BM, Richman J, et al. Comparing Gonioscopy With Visante and Cirrus Optical Coherence Tomography for Anterior Chamber Angle Assessment in Glaucoma Patients. J Glaucoma. 2016;25(2):177-83.\u003c/li\u003e\n\u003cli\u003ePark SB, Sung KR, Kang SY, Jo JW, Lee KS, Kook MS. Assessment of narrow angles by gonioscopy, Van Herick method and anterior segment optical coherence tomography. Jpn J Ophthalmol. 2011;55(4):343-50.\u003c/li\u003e\n\u003cli\u003eQuek DT, Narayanaswamy AK, Tun TA, Htoon HM, Baskaran M, Perera SA, et al. Comparison of two spectral domain optical coherence tomography devices for angle-closure assessment. Invest Ophthalmol Vis Sci. 2012;53(9):5131-6.\u003c/li\u003e\n\u003cli\u003eRigi M, Bell NP, Lee DA, Baker LA, Chuang AZ, Nguyen D, et al. Agreement between Gonioscopic Examination and Swept Source Fourier Domain Anterior Segment Optical Coherence Tomography Imaging. J Ophthalmol. 2016;2016:1727039.\u003c/li\u003e\n\u003cli\u003eJaseena K, Rekha PS. Agreement of gonioscopy and anterior segment-optical coherence tomography in the assessment of the anterior chamber angle: A cross-sectional study. Kerala Journal of Ophthalmology. 2022;34(1).\u003c/li\u003e\n\u003cli\u003eLune A, Prabhudesai A. A Comparative Study of Anterior Segment Optical Coherence Tomography and Gonioscopy in Detection of Narrow, Occludable Angles. Cureus. 2024;16(9):e69879.\u003c/li\u003e\n\u003cli\u003eDesmond T, Tran V, Maharaj M, Carnt N, White A. Diagnostic accuracy of AS-OCT vs gonioscopy for detecting angle closure: a systematic review and meta-analysis. Graefes Arch Clin Exp Ophthalmol. 2022;260(1):1-23.\u003c/li\u003e\n\u003cli\u003eYaisiri P, Panarojwongse N, Treesit I, Choontanom R, Jatuthong O, Iemsomboon W, et al. Comparison of Swept-Source Anterior Segment Ocular Coherence Tomography and Gonioscopy in Detecting Anterior Chamber Angle Closure. Clin Ophthalmol. 2025;19:699-711.\u003c/li\u003e\n\u003cli\u003eChansangpetch S, Nguyen A, Mora M, Badr M, He M, Porco TC, et al. Agreement of Anterior Segment Parameters Obtained From Swept-Source Fourier-Domain and Time-Domain Anterior Segment Optical Coherence Tomography. Invest Ophthalmol Vis Sci. 2018;59(3):1554-61.\u003c/li\u003e\n\u003cli\u003eAngmo D, Singh R, Chaurasia S, Yadav S, Dada T. Evaluation of anterior segment parameters with two anterior segment optical coherence tomography systems: Visante and Casia, in primary angle closure disease. Indian J Ophthalmol. 2019;67(4):500-4.\u003c/li\u003e\n\u003cli\u003eChan PP, Lai G, Chiu V, Chong A, Yu M, Leung CK. Anterior chamber angle imaging with swept-source optical coherence tomography: comparison between CASIAII and ANTERION. Sci Rep. 2020;10(1):18771.\u003c/li\u003e\n\u003cli\u003ePardeshi AA, Song AE, Lazkani N, Xie X, Huang A, Xu BY. Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices. Transl Vis Sci Technol. 2020;9(9):14.\u003c/li\u003e\n\u003cli\u003eWang YE, Li Y, Wang D, He M, Lin S. Comparison of factors associated with occludable angle between american Caucasians and ethnic Chinese. Invest Ophthalmol Vis Sci. 2013;54(12):7717-23.\u003c/li\u003e\n\u003cli\u003eOzaki M, Nongpiur ME, Aung T, He M, Mizoguchi T. Increased lens vault as a risk factor for angle closure: confirmation in a Japanese population. Graefes Arch Clin Exp Ophthalmol. 2012;250(12):1863-8.\u003c/li\u003e\n\u003cli\u003eMoghimi S, Chen R, Hamzeh N, Khatibi N, Lin SC. Qualitative evaluation of anterior segment in angle closure disease using anterior segment optical coherence tomography. J Curr Ophthalmol. 2016;28(4):170-5.\u003c/li\u003e\n\u003cli\u003eKwon J, Sung KR, Han S. Long-term Changes in Anterior Segment Characteristics of Eyes With Different Primary Angle-Closure Mechanisms. Am J Ophthalmol. 2018;191:54-63.\u003c/li\u003e\n\u003cli\u003eTian J, Marziliano P, Baskaran M, Wong HT, Aung T. Automatic anterior chamber angle assessment for HD-OCT images. IEEE Trans Biomed Eng. 2011;58(11):3242-9.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"gonioscopy, anterior segment optical coherence tomography, AS-OCT, angle closure, primary angle closure glaucoma","lastPublishedDoi":"10.21203/rs.3.rs-8752901/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8752901/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eThis study aimed to assess the level of agreement between anterior segment optical coherence tomography (AS-OCT) measurements obtained with the time-domain Visante\u0026reg; OCT and the swept-source DRI OCT Triton\u0026reg; in eyes with shallow anterior chambers under evaluation for angle closure, and was structured as an observational, cross-sectional design aimed at analyzing data obtained with two different types of anterior segment OCT devices.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eTwenty-three patients were evaluated by gonioscopy before AS-OCT imaging. Anterior segment images were acquired under dark conditions using both Visante\u0026reg; and DRI OCT Triton\u0026reg;. The agreement of angle closure diagnosis between gonioscopy and AS-OCT was assessed with first-order agreement coefficients (AC1). Bland-Altman plots were used to assess the agreement of quantitative parameters obtained by both OCT devices.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eSignificant differences were observed in all evaluated parameters. All angle-related measurements were higher with the DRI OCT Triton\u0026reg;, whereas all iris-related parameters were higher with the Visante\u0026reg;. Lens vault was significantly higher with the Visante\u0026reg; than with the DRI OCT Triton\u0026reg; (857.46 \u0026plusmn; 279.38 \u0026micro;m vs. 310.68 \u0026plusmn; 244.75 \u0026micro;m, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Anterior chamber width was significantly higher using DRI OCT Triton\u0026reg; than Visante\u0026reg; (11.91 \u0026plusmn; 0.43mm vs. 11.42 \u0026plusmn; 0.42 mm, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Agreement between devices ranged from good to excellent (ICC 0.61\u0026ndash;0.90). Gonioscopy showed better agreement with the Visante\u0026reg; (AC1\u0026thinsp;=\u0026thinsp;0.52) than with the DRI OCT Triton\u0026reg; (AC1\u0026thinsp;=\u0026thinsp;0.12).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eA substantial difference between parameters analyzed by AS-OCT devices was observed.\u003c/p\u003e","manuscriptTitle":"Disagreement between anterior segment optical coherence tomography devices in eyes with a shallow anterior chamber","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-02-04 12:41:12","doi":"10.21203/rs.3.rs-8752901/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"569e0ab4-8dc5-4fd5-b30f-7cf836c1f1fa","owner":[],"postedDate":"February 4th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-19T21:24:13+00:00","versionOfRecord":[],"versionCreatedAt":"2026-02-04 12:41:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8752901","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8752901","identity":"rs-8752901","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}