Comparison of slit lamp based anterior chamber depth measurement with Lenstar LS 900 and its correaltion with Anterior Chamber Angle Assessed by Anterior segment OCT

Comparison of slit lamp based anterior chamber depth measurement with Lenstar LS 900 and its correaltion with Anterior Chamber Angle Assessed by Anterior segment OCT | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comparison of slit lamp based anterior chamber depth measurement with Lenstar LS 900 and its correaltion with Anterior Chamber Angle Assessed by Anterior segment OCT Sandra, Ahmed Shalash, Heba Magdy, Alia Noureldine This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9065302/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The anterior chamber depth (ACD) is a vital metric for evaluating angle-closure glaucoma and for strategizing cataract surgery or phakic intraocular lens (IOL) implantation. This study aimed to evaluate the mean difference in anterior chamber depth (ACD) measurements obtained by means of Smith’s technique and the Lenstar 900, as well as to ascertain its association with the anterior chamber angle (ACA) using anterior segment optical coherence tomography (AS-OCT). Methods This cross-sectional analytic study comprised 70 clean-corneaed people over 40 of both genders. All patients had a basic slit lamp examination of the anterior segment, including Smith's 1979 technique of measuring axial anterior chamber depth (ACD). Then, a variety of refractive states corresponding to axial length were determined by combining non-contact optical biometry (Lenstar 900) with anterior segment optical coherence tomography (AS-OCT). Results A significant difference was observed between Smith ACD (3.08 ± 0.52) and Lenstar ACD (3.22 ± 0.49) (P < 0.001), with a mean difference of -0.13 (-0.19: -0.07 CI), particularly evident in patients with short and average axial lengths; Smith’s technique tends to underestimate the ACD relative to Lenstar 900. This variation is insufficient to be clinically or practically important when contemplating cataract surgery or intraocular lens implantation. The estimations of ACD derived from Smith's technique show a favorable association with ACA measurements obtained using AS-OCT. Conclusions The Smith method enables accelerated measurement of axial ACD without the need for specialized slit-lamp attachments. It is a realizable, non-invasive, and rapid technique that is appropriate for the initial assessment of patients with shallow anterior chambers. Ophthalmology Anterior Chamber Depth Anterior Segment OCT Lenstar 900 Smith’s Method Figures Figure 1 Introduction In the last twenty years, axial anterior chamber depth (ACD) measurements have gained significance in the assessment of narrow anterior chamber angles (ACA), a primary risk factor for angle-closure glaucoma. This is particularly pertinent in those aged 30 and beyond, when there is a notable reduction in axial anterior chamber depth, perhaps attributable to the progressive increase in lens thickness or in those predisposed to angle-closure glaucoma (ref. 1). ACD denotes the distance from the corneal endothelium to the anterior capsule of the crystalline lens. The typical depth of ACD in healthy persons is around 3 mm (ref. 1). The measurement can be conducted with relative simplicity using a slit lamp; however, familiarity with this method is restricted. Consequently, more costly technologies are employed, such as anterior segment optical coherence tomography (AS-OCT) from Optovue (California, USA), the IOL Master 500, and the Lenstar-LS900 from Haag–Streit AG (Köniz, Switzerland). As a result, access to these technologies in primary care facilities in underserved regions of low- to middle-income countries may be constrained (ref. 2). The ACD assessment methodology introduced by Jacobs and enhanced by Smith is direct and economical. The Smith approach and its variations have been validated by several authors. It allows the physician to get precise measurements of axial anterior chamber depth without any attachments to the slit-lamp biomicroscope. The axial ACD measurements are accurate to ± 0.25 mm ± 0.2 mm in relation to pachymetry and ± 0.42 mm in relation to ultrasonography (ref. 3). The central corneal thickness does not influence the ACD estimate obtained with this approach. Estimates of the just touching slit length (JTSL) axial ACD are devoid of inter- and intra-observer variability (ref. 4). This work is intended to investigate the difference in measuring ACD between the Smith method and the optical Lenstar 900 and establish the association with the angle status using anterior segment OCT in different refractive states. Patients and Methods This cross-sectional analytic study was carried out on 71 patients (71 eyes) aged > 40 years old, both sexes, with clear corneas, clear lenses, nuclear sclerosis, and immature and mature senile cataracts. The study was done from March 2022 to March 2023 following endorsement from the Institutional Review Board of Cairo University Hospitals, Cairo, Egypt. Informed consent was acquired from the patients. Exclusion criteria were patients with intumescent or hypermature senile cataract, pseudophakic patients, any history of previous ocular trauma or surgery, presence of corneal opacities, high myopia (spherical equivalent > 6 D), high hypermetropia (spherical equivalent > 4 D), and presence of any post-uveitic synechia. The eyes of all participants were subjected to BCVA using Snellen’s Chart. Non-dilated slit lamp (Haag-Streit 900 S) examination of the anterior segment, encompassing quantification of anterior chamber depth (ACD) via Smith’s technique as delineated by Redmond Smith. Technique: (Fig. 1 ) To measure the ACD on the right side, the equipment was configured with the slit beam positioned to the operator's left, and conversely for the opposite eye. The right eyepiece was designated for the right eye, while the left eyepiece was allocated for the left eye. The microscope was oriented to align directly with the patient's optical axis, and the slit beam axis was adjusted to 60°, whereas the patient was directed to gaze straight ahead. The apparatus was positioned anteriorly using the joystick until the slit beam was directed at the cornea. The beam was then oriented horizontally; the width of the slit is not critically significant. The length of the slit beam was reduced using the supplied knurled knob. Two photos from the slits were acquired here: A precise, narrow incision on the left cornea and a distorted, unfocused slit image on the right anterior lens capsule, accompanied by an optically void space (Position A). The slit was extended until the gap was completely resolved (Position B). At present, the optical conditions resulted in the left margin of the corneal slit image coinciding with the right margin of the slit image observed at the anterior surface of the lens. Three readings were taken, and the mean is multiplied by 1.31 and not 1.4 as proposed by Smith (ref.5) based on the study published by Barrett et al. (ref.6) who evaluated the Smith ACD through comparative analysis with pachymetric and ultrasonographic modalities and revealed that the quantitative assessments were accurate within ± 0.33 when compared with the pachymeter, and the constant value producing optimal concordance was 1.31 and not 1.4 as quoted by Smith. The ACD, the AD, and the axial length were obtained by Lenstar LS 900, a non-contact optical biometry that uses OLCR. Triplicate measurements were obtained by a single blinded examiner for all and documented. The angle width (ACA) was measured in four quadrants using AS-OCT (Optovue), defined as the angle in degrees between a tangent to the trabecular meshwork surface and a tangent to the peripheral third of the iris. This was documented using a five-point category scale (0°, 10°, 20°, 30°, > 40°) as per the methodology outlined by Shaffer. The mean angle was determined by summing the angle measurements for each quadrant and dividing by four. Statistical analysis Data were statistically characterized using mean ± standard deviation (± SD), range, or frequencies (number of instances) and percentages as applicable. The Kolmogorov-Smirnov test was used to assess the normality assumption of the numerical data. Within-group comparison between the study variables was done using a paired t-test. The relationship among different variables was assessed using Pearson's moment correlation for linear relationships of normally distributed variables and Spearman's rank correlation for non-normally distributed or non-linear monotonic relationships. Statistical significance was established by two-sided p-values below 0.05. All statistical analyses were performed using IBM SPSS (Statistical Package for the Social Sciences; IBM Corp, Armonk, NY, USA) version 22 for Microsoft Windows. Results Demographics data, Smith ACD, Lenstar ACD, Lenstar AD, Lenstar AL, angle by AS-OCT, and Lenstar AL grouping were enumerated in this table. ( Table 1) There were significant differences between Smith and Lenstar measurements for both ACD and AD (P < 0.001). Specifically, Smith ACD was lower than Lenstar ACD, with a mean difference of approximately − 0.13 (95% CI: − 0.19 to − 0.07) and limits ranging from − 0.63 to 0.37, while Smith ACD compared to Lenstar AD showed a mean difference of 0.361 (95% CI: 0.31 to 0.41) with limits from − 0.07 to 0.79. Therefore, Smith and Lenstar measurements statistically differ significantly across both ACD and AD parameters, and this was accentuated among subjects with mean axial lengths. (Table 2) In contrast, for long axial length (AL) cases, the difference between Smith ACD and Lenstar ACD was not significant, exhibiting a mean differential of − 0.17 (95% CI: − 0.54 to 0.19) and limits from − 0.75 to 0.39. Additionally, a significant difference was observed between Smith ACD and Lenstar AD in this subgroup (P = 0.024), presenting a mean difference of 0.27 (95% CI: 0.057–0.479) and limits from − 0.07 to 0.60. These findings indicate that measurement discrepancies vary by parameter and subgroup, with Lenstar AD generally differing significantly from Smith ACD, while Lenstar ACD shows less difference in long AL cases. (Table 3) Correlation with anterior segment OCT angle: In general, there was a significant positive strong correlation between Smith ACD and Lenstar ACD and Lenstar AD (r = 0.872, 0.903, and P < 0.001, respectively), and there was a significant positive moderate correlation between Smith ACD and Angle by AS-OCT (r = 0.531 and P < 0.001), and this was more evident in patients with average axial lengths. ( Table 4) Discussion There is an insufficient understanding of the assessment of anterior chamber depth (ACD) utilizing Smith’s technique with a slit lamp in routine clinical practice. In this study, there was a notable disparity between Smith ACD and Lenstar ACD, with a mean difference of -0.13. Smith’s technique somewhat underestimated the ACD in comparison to Lenstar 900, with this discrepancy being more significant in patients with short AL (1 patient) and medium AL (66 patients). Bausch & Lomb, upon launching its angle-supported Phakic NuVita (ref. 7), determined that the necessary IOL power fluctuates by 0.1 D for every 0.2 mm of ACD, a variation deemed insufficient to produce any significant alteration in refractive result. No substantial difference was seen between the two techniques in individuals with extended AL (5 cases). Our research was the second to evaluate the average disparity between Smith ACD and Lenstar ACD in normal phakic eyes. In India, Vanita et al. (ref. 2) reported that ACD was decreased in PEX participants relative to normal controls. Nevertheless, the Smith approach somewhat overstated the ACD in comparison to AS-OCT and Lenstar; yet, all data fall below the 95% lower limit of agreement and are uniformly distributed throughout all Bland–Altman plots, implying a lack of correlation between average ACD values and device-related variances. The consistency of ACD measurement outcomes was superior between Smith ACD and AS-OCT compared to Smith ACD and Lenstar, with the highest agreement seen between AS-OCT and Lenstar, both of which are automated equipment independent of observer bias in PEX patients and controls. Smith’s method is a clinical method that may have observer bias. In 2000, Osuobeni et al. (ref. 8) evaluated the intraobserver repeatability of Smith’s method and proved the high repeatability of this technique with comparable results to those reported by A-scan ultrasonographic measures of ACD. In the current study, we tried to eliminate observer bias by taking three readings for each patient by a single observer, and the mean of these was calculated and used. We also assessed the mean difference between Smith ACD and Lenstar AD. The Lenstar ACD is equal to the actual AD + the central corneal thickness (CCT). No available studies addressed this issue, although it is important, especially in glaucomatous patients, where the actual aqueous depth is mainly being assessed. A significant difference existed between Smith ACD and Lenstar AD (mean = 2.72 ± 0.46), with a mean difference of 0.361 (95% CI: 0.31–0.41); this difference is much higher than that of Smith ACD and Lenstar ACD, concluding that measuring the ACD using Smith’s method is more comparable to Lenstar ACD rather than Lenstar AD. The present study aimed to assess the relation between the axial ACD measured clinically by Smith’s method and the status of the ACA measured by AS-OCT. Results showed a positive correlation between Smith ACD and the ACA measured by AS-OCT in different ALs (r = 0.531). Al Mubrad et al. (ref. 9) found that the Smith-method JTSL approach may serve as a non-invasive, quick screening instrument to screen for individuals susceptible to angle-closure onset during regular ophthalmological examinations. It is to be noted that in that study, they compared the axial ACD in the 3 groups using Smith’s method and referred to the angle status using the Van Herick technique and gonioscopy, not AS-OCT. The diagnostic accuracy of slit lamp measurement of peripheral and axial ACD using Van Herick and Smith’s method, respectively, was assessed in 2015 by Dabesia et al. (ref. 10), who concluded that Smith’s method had a lower sensitivity and specificity compared to the Van Herick technique; however, it is a rapid, qualitative, and simple method that can be used in succession with the Van Herick technique or when the Van Herick technique is not possible, as in the case of the presence of dense arcus senilis. This procedure's value lies in its capacity for quick screening of axial ACD measurement without requiring specialist slit-lamp attachments. It is non-invasive and measurable, providing a dependable assessment of anterior chamber depth, facilitating swift screening of individuals with shallow anterior chambers. It is particularly helpful in remote locations or fundamental eye care clinics that may lack technological advances. Although the automated modalities have the advantages of being faster and requiring less technical skill, they also have inter-observer heterogeneity. However, its biggest drawback is that it is a costly technological modality, which may explain why outreach primary centers do not have access to it. Therefore, possessing expertise and proficiency in this essential skill is considered beneficial and highly valued within the therapeutic practices of ophthalmic care professionals. Limitations of the study included that the sample size was not large enough, with a small number of candidates with short (1 patient) and long AL (5 patients). Nevertheless, as the principal purpose of this research was to examine Smith’s method in normal phakic eyes, selecting the average axial length (AL) group was appropriate. AS-OCT imaging was performed in only 33 out of 71 patients; however, to date, there is no prospective clinical research directly correlating the axial anterior chamber depth (ACD) measured by Smith’s method with anterior chamber angle (ACA) status assessed via AS-OCT. This study can be the beginning of future studies to correlate the axial ACD and the ACA using different automated modalities. Conclusions The Smith approach for axial ACD estimate using the slit lamp may be used as an economical, rapid, quantifiable, non-invasive screening technique during a standard clinical examination. We recommend its use, especially in primary outreach locations where sophisticated equipment may be lacking. Declarations Conflict of interest: The authors declare no conflict of interest. Funding: None. Authors' contributions: A.S. generated the idea, interpreted the data, and revised the manuscript. H.M. wrote and revised the manuscript. S.R. collected and analyzed the data and wrote the manuscript. A.N. interpreted the data, wrote, and revised the manuscript. All authors read and approved the final manuscript. References Van Herick W, Shaffer RN, Schwartz A (1969) Estimation of width of angle of anterior chamber. Incidence and significance of the narrow angle. Am J Ophthalmol 68:626–629 Pathak Ray V, Ramesh SB, Rathi V (2021) Slit-lamp measurement of anterior chamber depth and its agreement with anterior segment optical coherence tomography and Lenstar LS 900 in pseudoexfoliation and normal eyes. Indian J Ophthalmol 69:2469–2474 Shimizu E, Tanaka K, Nishimura H, Agata N, Tanji M, Nakayama S et al (2024) The use of artificial intelligence for estimating anterior chamber depth from slit-lamp images developed using anterior-segment optical coherence tomography. Bioengineering 11:100–110 Sidek Ni, Yusof F (2021) The repeatability of smith's method in measuring anterior chamber depth. J Allied Health Sci 5:2262 Smith RJ (1979) A new method of estimating the depth of the anterior chamber. Br J Ophthalmol 63:215–220 Barrett BT, McGraw PV, Murray LA, Murgatroyd P (1996) Anterior chamber depth measurement in clinical practice. Optom Vis Sci 73:482–486 Vetrugno M, Cardascia N, Cardia L (2000) Anterior chamber depth measured by two methods in myopic and hyperopic phakic IOL implant. Br J Ophthalmol 84:1113–1116 Osuobeni EP, Oduwaiye KA, Ogbuehi KC (2000) Intra-observer repeatability and inter-observer agreement of the Smith method of measuring the anterior chamber depth. Ophthalmic Physiol Opt 20:153–159 Al-Mubrad TM, Ogbuehi KC (2006) Smith-method assessment of anterior chamber depth for screening for narrow anterior chamber angles. Indian J Ophthalmol 54:165–168 Dabasia PL, Edgar DF, Murdoch IE, Lawrenson JG (2015) Noncontact screening methods for the detection of narrow anterior chamber angles. Invest Ophthalmol Vis Sci 56:3929–3935 Tables Table 1: Demographics data, smith ACD, Lenstar ACD, Lenstar AD, Lenstar AL, angle by AS-OCT and Lenstar AL grouping of the studied patients N=71 Age (years) 62.4 ± 9.69 Sex Male 31 (43.66%) Female 40 (56.34%) Side Right 32 (45.07%) Left 39 (54.93%) Smith ACD (mm) 3.08 ± 0.52 Lenstar ACD (mm) 3.2 ± 0.49 Lenstar AD (mm) 2.7 ± 0.46 Lenstar AL (mm) 23.3 ± 1.47 Angle by AS-OCT (°) 43.3 ± 9.87 Lenstar AL grouping Short 1 (1.41%) Average 65 (91.55%) Long 5 (7.04%) Data are presented as mean ± SD or frequency (%) ACD: Anterior chamber depth, AD: aqueous depth, AL: axial length. Table 2: Smith ACD and Lenstar ACD, AD and ACD of short and average AL cases of the studied patients Smith ACD (n=71) Lenstar ACD (n=71) Mean (95% CI) Lower limit (95% CI) Upper limit (95% CI) P Mean± SD 3.08 ± 0.52 3.22 ± 0.49 - 0.13 (-0.19: -0.07 ) -0.63 (-0.73 :-0.52) 0.37 (0.26: 0.47) <0.001* AD (n=71) Mean± SD 3.08 ± 0.52 2.72 ± 0.46 0.361 (0.31: 0.41) -0.07 (-0.16: 0.02) 0.79 (0.71: 0.89) <0.001* Data are presented as mean ± SD. *: significant P value ≤0.05. CI: confidence interval, ACD: Anterior chamber depth, AL: Axial length. Table 3: Smith ACD and Lenstar AD of short and average AL cases, Lenstar ACD and AD of long AL cases Smith ACD (n=66) Lenstar AD (n=66) Mean (95% CI) Lower limit (95% CI) Upper limit (95% CI) P Mean± SD 3.06 ± 0.5 2.69 ± 0.45 0.37 (0.31: 0.42) -0.07 (-0.17: 0.02) 0.81 (0.71: 0.90) <0.001* Lenstar ACD (n=5) Mean± SD 3.36 ± 0.64 3.54 ± 0.49 -0.17 (-0.54: 0.19) -0.75 (-1.41: -0.08) 0.39 (-0.27: 1.07) 0.253 Lenstar AD (n=5) Mean± SD 3.36 ± 0.64 3.1 ± 0.49 0.27 (0.057: 0.479) -0.07 (-0.46: 0.32) 0.60 (0.21: 0.99) 0.024* Data are presented as mean ± SD. *: significant P value ≤0.05. CI: confidence interval, ACD: Anterior chamber depth, AL: Axial length. Table 4: Correlation between Smith ACD and Lenstar ACD, Lenstar AD and Angle by AS-OCT of the studied patients, short, average and long AL cases Lenstar ACD Lenstar AD Angle by AS-OCT Smith ACD r 0.872 0.903 0.531 P <0.001* <0.001* 0.001* long AL cases Lenstar ACD Lenstar AD Smith ACD r 0.898 0.987 P 0.038* 0.002* r: Pearson correlation, *: significant P value ≤0.05. ACD: Anterior chamber depth, AD: aqueous depth, AL: Axial length. Additional Declarations The authors declare no competing interests. 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. We do this by developing innovative software and high quality services for the global research community. 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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-9065302","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":602636092,"identity":"add9f0f5-e0dd-400c-9d9c-b1f5a3b8f728","order_by":0,"name":"Sandra","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBklEQVRIiWNgGAWjYDAD9gYg8YHHBkgyNh4gSgvPAaDSGTJpIC0NxGtp5rE5DObg1SLf3nv4w8cddfI8EsnPH/PknLdb234YaEuNTTQuLQZnzqVJzjxz2LBHIs2wcc6Z28nbziQCtRxLy23ApUUix4yZt+0A437pBMOGtz23k80OALUwNhzGqUV+Ro7xZ962Ovse6fSPDbz/ziWbnX+IXwvDjRwDad425sQe6RzDRh6eA3ZmNwjYYnDmjJnkzLbDyT3ybwpnzuBJTjC7AbQlAY9f5Nt7jD98bKuz7eE5vuHDBx47e7Pz6Q8ffKixwe0wdJAIVplArHIQsCdF8SgYBaNgFIwMAAD1bWc2zH7uowAAAABJRU5ErkJggg==","orcid":"","institution":"Cairo university","correspondingAuthor":true,"prefix":"","firstName":"","middleName":"","lastName":"Sandra","suffix":""},{"id":602636166,"identity":"d5ef7cf9-2738-495a-9879-2c9886230db7","order_by":1,"name":"Ahmed Shalash","email":"","orcid":"","institution":"Cairo university","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Shalash","suffix":""},{"id":602636212,"identity":"b602ac6a-2610-47bb-ae32-95939417b244","order_by":2,"name":"Heba Magdy","email":"","orcid":"","institution":"Cairo university","correspondingAuthor":false,"prefix":"","firstName":"Heba","middleName":"","lastName":"Magdy","suffix":""},{"id":602636213,"identity":"52f88b75-293a-41b0-b4e0-796b9329a139","order_by":3,"name":"Alia Noureldine","email":"","orcid":"","institution":"Cairo university","correspondingAuthor":false,"prefix":"","firstName":"Alia","middleName":"","lastName":"Noureldine","suffix":""}],"badges":[],"createdAt":"2026-03-08 15:39:41","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9065302/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9065302/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":104341304,"identity":"5384a3cd-cd83-4604-b5c2-dcaceb55225b","added_by":"auto","created_at":"2026-03-10 16:48:21","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":9524,"visible":true,"origin":"","legend":"\u003cp\u003eSmith Method for measurement of ACD\u003c/p\u003e","description":"","filename":"photo20260308174309.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9065302/v1/ee96a94241a80d1055909e8c.jpg"},{"id":104405650,"identity":"adaad2a1-4397-4fc3-b16a-65c450cf1b56","added_by":"auto","created_at":"2026-03-11 12:23:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":723223,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9065302/v1/b60db0cc-8d27-47ea-86fe-a48f5f84329c.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003eComparison of slit lamp based anterior chamber depth measurement with Lenstar LS 900 and its correaltion with Anterior Chamber Angle Assessed by Anterior segment OCT \u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIn the last twenty years, axial anterior chamber depth (ACD) measurements have gained significance in the assessment of narrow anterior chamber angles (ACA), a primary risk factor for angle-closure glaucoma. This is particularly pertinent in those aged 30 and beyond, when there is a notable reduction in axial anterior chamber depth, perhaps attributable to the progressive increase in lens thickness or in those predisposed to angle-closure glaucoma (ref. 1).\u003c/p\u003e \u003cp\u003eACD denotes the distance from the corneal endothelium to the anterior capsule of the crystalline lens. The typical depth of ACD in healthy persons is around 3 mm (ref. 1).\u003c/p\u003e \u003cp\u003eThe measurement can be conducted with relative simplicity using a slit lamp; however, familiarity with this method is restricted. Consequently, more costly technologies are employed, such as anterior segment optical coherence tomography (AS-OCT) from Optovue (California, USA), the IOL Master 500, and the Lenstar-LS900 from Haag\u0026ndash;Streit AG (K\u0026ouml;niz, Switzerland). As a result, access to these technologies in primary care facilities in underserved regions of low- to middle-income countries may be constrained (ref. 2).\u003c/p\u003e \u003cp\u003eThe ACD assessment methodology introduced by Jacobs and enhanced by Smith is direct and economical. The Smith approach and its variations have been validated by several authors. It allows the physician to get precise measurements of axial anterior chamber depth without any attachments to the slit-lamp biomicroscope. The axial ACD measurements are accurate to \u0026plusmn;\u0026thinsp;0.25 mm\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 mm in relation to pachymetry and \u0026plusmn;\u0026thinsp;0.42 mm in relation to ultrasonography (ref. 3).\u003c/p\u003e \u003cp\u003eThe central corneal thickness does not influence the ACD estimate obtained with this approach. Estimates of the just touching slit length (JTSL) axial ACD are devoid of inter- and intra-observer variability (ref. 4).\u003c/p\u003e \u003cp\u003eThis work is intended to investigate the difference in measuring ACD between the Smith method and the optical Lenstar 900 and establish the association with the angle status using anterior segment OCT in different refractive states.\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cp\u003eThis cross-sectional analytic study was carried out on 71 patients (71 eyes) aged\u0026thinsp;\u0026gt;\u0026thinsp;40 years old, both sexes, with clear corneas, clear lenses, nuclear sclerosis, and immature and mature senile cataracts. The study was done from March 2022 to March 2023 following endorsement from the Institutional Review Board of Cairo University Hospitals, Cairo, Egypt. Informed consent was acquired from the patients.\u003c/p\u003e \u003cp\u003eExclusion criteria were patients with intumescent or hypermature senile cataract, pseudophakic patients, any history of previous ocular trauma or surgery, presence of corneal opacities, high myopia (spherical equivalent\u0026thinsp;\u0026gt;\u0026thinsp;6 D), high hypermetropia (spherical equivalent\u0026thinsp;\u0026gt;\u0026thinsp;4 D), and presence of any post-uveitic synechia.\u003c/p\u003e \u003cp\u003eThe eyes of all participants were subjected to BCVA using Snellen\u0026rsquo;s Chart. Non-dilated slit lamp (Haag-Streit 900 S) examination of the anterior segment, encompassing quantification of anterior chamber depth (ACD) via Smith\u0026rsquo;s technique as delineated by Redmond Smith.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eTechnique: (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e)\u003c/h2\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTo measure the ACD on the right side, the equipment was configured with the slit beam positioned to the operator's left, and conversely for the opposite eye. The right eyepiece was designated for the right eye, while the left eyepiece was allocated for the left eye. The microscope was oriented to align directly with the patient's optical axis, and the slit beam axis was adjusted to 60\u0026deg;, whereas the patient was directed to gaze straight ahead. The apparatus was positioned anteriorly using the joystick until the slit beam was directed at the cornea. The beam was then oriented horizontally; the width of the slit is not critically significant. The length of the slit beam was reduced using the supplied knurled knob. Two photos from the slits were acquired here: A precise, narrow incision on the left cornea and a distorted, unfocused slit image on the right anterior lens capsule, accompanied by an optically void space (Position A). The slit was extended until the gap was completely resolved (Position B). At present, the optical conditions resulted in the left margin of the corneal slit image coinciding with the right margin of the slit image observed at the anterior surface of the lens.\u003c/p\u003e \u003cp\u003eThree readings were taken, and the mean is multiplied by 1.31 and not 1.4 as proposed by Smith (ref.5) based on the study published by Barrett et al. (ref.6) who evaluated the Smith ACD through comparative analysis with pachymetric and ultrasonographic modalities and revealed that the quantitative assessments were accurate within \u0026plusmn;\u0026thinsp;0.33 when compared with the pachymeter, and the constant value producing optimal concordance was 1.31 and not 1.4 as quoted by Smith.\u003c/p\u003e \u003cp\u003eThe ACD, the AD, and the axial length were obtained by Lenstar LS 900, a non-contact optical biometry that uses OLCR. Triplicate measurements were obtained by a single blinded examiner for all and documented.\u003c/p\u003e \u003cp\u003eThe angle width (ACA) was measured in four quadrants using AS-OCT (Optovue), defined as the angle in degrees between a tangent to the trabecular meshwork surface and a tangent to the peripheral third of the iris. This was documented using a five-point category scale (0\u0026deg;, 10\u0026deg;, 20\u0026deg;, 30\u0026deg;, \u0026gt;\u0026thinsp;40\u0026deg;) as per the methodology outlined by Shaffer. The mean angle was determined by summing the angle measurements for each quadrant and dividing by four.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eData were statistically characterized using mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (\u0026plusmn;\u0026thinsp;SD), range, or frequencies (number of instances) and percentages as applicable. The Kolmogorov-Smirnov test was used to assess the normality assumption of the numerical data. Within-group comparison between the study variables was done using a paired t-test. The relationship among different variables was assessed using Pearson's moment correlation for linear relationships of normally distributed variables and Spearman's rank correlation for non-normally distributed or non-linear monotonic relationships. Statistical significance was established by two-sided p-values below 0.05. All statistical analyses were performed using IBM SPSS (Statistical Package for the Social Sciences; IBM Corp, Armonk, NY, USA) version 22 for Microsoft Windows.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eDemographics data, Smith ACD, Lenstar ACD, Lenstar AD, Lenstar AL, angle by AS-OCT, and Lenstar AL grouping were enumerated in this table. (\u003cb\u003eTable\u0026nbsp;1)\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThere were significant differences between Smith and Lenstar measurements for both ACD and AD (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Specifically, Smith ACD was lower than Lenstar ACD, with a mean difference of approximately \u0026minus;\u0026thinsp;0.13 (95% CI: \u0026minus;\u0026thinsp;0.19 to \u0026minus;\u0026thinsp;0.07) and limits ranging from \u0026minus;\u0026thinsp;0.63 to 0.37, while Smith ACD compared to Lenstar AD showed a mean difference of 0.361 (95% CI: 0.31 to 0.41) with limits from \u0026minus;\u0026thinsp;0.07 to 0.79. Therefore, Smith and Lenstar measurements statistically differ significantly across both ACD and AD parameters, and this was accentuated among subjects with mean axial lengths. \u003cb\u003e(Table\u0026nbsp;2)\u003c/b\u003e\u003c/p\u003e \u003cp\u003eIn contrast, for long axial length (AL) cases, the difference between Smith ACD and Lenstar ACD was not significant, exhibiting a mean differential of \u0026minus;\u0026thinsp;0.17 (95% CI: \u0026minus;\u0026thinsp;0.54 to 0.19) and limits from \u0026minus;\u0026thinsp;0.75 to 0.39. Additionally, a significant difference was observed between Smith ACD and Lenstar AD in this subgroup (P\u0026thinsp;=\u0026thinsp;0.024), presenting a mean difference of 0.27 (95% CI: 0.057\u0026ndash;0.479) and limits from \u0026minus;\u0026thinsp;0.07 to 0.60.\u003c/p\u003e \u003cp\u003eThese findings indicate that measurement discrepancies vary by parameter and subgroup, with Lenstar AD generally differing significantly from Smith ACD, while Lenstar ACD shows less difference in long AL cases. \u003cb\u003e(Table\u0026nbsp;3)\u003c/b\u003e\u003c/p\u003e\n\u003ch3\u003eCorrelation with anterior segment OCT angle:\u003c/h3\u003e\n\u003cp\u003eIn general, there was a significant positive strong correlation between Smith ACD and Lenstar ACD and Lenstar AD (r\u0026thinsp;=\u0026thinsp;0.872, 0.903, and P\u0026thinsp;\u0026lt;\u0026thinsp;0.001, respectively), and there was a significant positive moderate correlation between Smith ACD and Angle by AS-OCT (r\u0026thinsp;=\u0026thinsp;0.531 and P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), and this was more evident in patients with average axial lengths. (\u003cb\u003eTable\u0026nbsp;4)\u003c/b\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThere is an insufficient understanding of the assessment of anterior chamber depth (ACD) utilizing Smith\u0026rsquo;s technique with a slit lamp in routine clinical practice. In this study, there was a notable disparity between Smith ACD and Lenstar ACD, with a mean difference of -0.13. Smith\u0026rsquo;s technique somewhat underestimated the ACD in comparison to Lenstar 900, with this discrepancy being more significant in patients with short AL (1 patient) and medium AL (66 patients). Bausch \u0026amp; Lomb, upon launching its angle-supported Phakic NuVita (ref. 7), determined that the necessary IOL power fluctuates by 0.1 D for every 0.2 mm of ACD, a variation deemed insufficient to produce any significant alteration in refractive result. No substantial difference was seen between the two techniques in individuals with extended AL (5 cases).\u003c/p\u003e \u003cp\u003eOur research was the second to evaluate the average disparity between Smith ACD and Lenstar ACD in normal phakic eyes. In India, Vanita et al. (ref. 2) reported that ACD was decreased in PEX participants relative to normal controls. Nevertheless, the Smith approach somewhat overstated the ACD in comparison to AS-OCT and Lenstar; yet, all data fall below the 95% lower limit of agreement and are uniformly distributed throughout all Bland\u0026ndash;Altman plots, implying a lack of correlation between average ACD values and device-related variances. The consistency of ACD measurement outcomes was superior between Smith ACD and AS-OCT compared to Smith ACD and Lenstar, with the highest agreement seen between AS-OCT and Lenstar, both of which are automated equipment independent of observer bias in PEX patients and controls.\u003c/p\u003e \u003cp\u003eSmith\u0026rsquo;s method is a clinical method that may have observer bias. In 2000, Osuobeni et al. (ref. 8) evaluated the intraobserver repeatability of Smith\u0026rsquo;s method and proved the high repeatability of this technique with comparable results to those reported by A-scan ultrasonographic measures of ACD.\u003c/p\u003e \u003cp\u003eIn the current study, we tried to eliminate observer bias by taking three readings for each patient by a single observer, and the mean of these was calculated and used. We also assessed the mean difference between Smith ACD and Lenstar AD. The Lenstar ACD is equal to the actual AD\u0026thinsp;+\u0026thinsp;the central corneal thickness (CCT). No available studies addressed this issue, although it is important, especially in glaucomatous patients, where the actual aqueous depth is mainly being assessed. A significant difference existed between Smith ACD and Lenstar AD (mean\u0026thinsp;=\u0026thinsp;2.72\u0026thinsp;\u0026plusmn;\u0026thinsp;0.46), with a mean difference of 0.361 (95% CI: 0.31\u0026ndash;0.41); this difference is much higher than that of Smith ACD and Lenstar ACD, concluding that measuring the ACD using Smith\u0026rsquo;s method is more comparable to Lenstar ACD rather than Lenstar AD.\u003c/p\u003e \u003cp\u003eThe present study aimed to assess the relation between the axial ACD measured clinically by Smith\u0026rsquo;s method and the status of the ACA measured by AS-OCT. Results showed a positive correlation between Smith ACD and the ACA measured by AS-OCT in different ALs (r\u0026thinsp;=\u0026thinsp;0.531). Al Mubrad et al. (ref. 9) found that the Smith-method JTSL approach may serve as a non-invasive, quick screening instrument to screen for individuals susceptible to angle-closure onset during regular ophthalmological examinations.\u003c/p\u003e \u003cp\u003eIt is to be noted that in that study, they compared the axial ACD in the 3 groups using Smith\u0026rsquo;s method and referred to the angle status using the Van Herick technique and gonioscopy, not AS-OCT.\u003c/p\u003e \u003cp\u003eThe diagnostic accuracy of slit lamp measurement of peripheral and axial ACD using Van Herick and Smith\u0026rsquo;s method, respectively, was assessed in 2015 by Dabesia et al. (ref. 10), who concluded that Smith\u0026rsquo;s method had a lower sensitivity and specificity compared to the Van Herick technique; however, it is a rapid, qualitative, and simple method that can be used in succession with the Van Herick technique or when the Van Herick technique is not possible, as in the case of the presence of dense arcus senilis.\u003c/p\u003e \u003cp\u003eThis procedure's value lies in its capacity for quick screening of axial ACD measurement without requiring specialist slit-lamp attachments. It is non-invasive and measurable, providing a dependable assessment of anterior chamber depth, facilitating swift screening of individuals with shallow anterior chambers. It is particularly helpful in remote locations or fundamental eye care clinics that may lack technological advances.\u003c/p\u003e \u003cp\u003eAlthough the automated modalities have the advantages of being faster and requiring less technical skill, they also have inter-observer heterogeneity. However, its biggest drawback is that it is a costly technological modality, which may explain why outreach primary centers do not have access to it. Therefore, possessing expertise and proficiency in this essential skill is considered beneficial and highly valued within the therapeutic practices of ophthalmic care professionals.\u003c/p\u003e \u003cp\u003e \u003cb\u003eLimitations\u003c/b\u003e of the study included that the sample size was not large enough, with a small number of candidates with short (1 patient) and long AL (5 patients). Nevertheless, as the principal purpose of this research was to examine Smith\u0026rsquo;s method in normal phakic eyes, selecting the average axial length (AL) group was appropriate. AS-OCT imaging was performed in only 33 out of 71 patients; however, to date, there is no prospective clinical research directly correlating the axial anterior chamber depth (ACD) measured by Smith\u0026rsquo;s method with anterior chamber angle (ACA) status assessed via AS-OCT. This study can be the beginning of future studies to correlate the axial ACD and the ACA using different automated modalities.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe Smith approach for axial ACD estimate using the slit lamp may be used as an economical, rapid, quantifiable, non-invasive screening technique during a standard clinical examination.\u003c/p\u003e \u003cp\u003eWe recommend its use, especially in primary outreach locations where sophisticated equipment may be lacking.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003cstrong\u003eConflict of interest:\u003c/strong\u003e \u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e \u003cp\u003eNone.\u003c/p\u003e\u003ch2\u003eAuthors' contributions:\u003c/h2\u003e \u003cp\u003eA.S. generated the idea, interpreted the data, and revised the manuscript. H.M. wrote and revised the manuscript. S.R. collected and analyzed the data and wrote the manuscript. A.N. interpreted the data, wrote, and revised the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eVan Herick W, Shaffer RN, Schwartz A (1969) Estimation of width of angle of anterior chamber. Incidence and significance of the narrow angle. Am J Ophthalmol 68:626\u0026ndash;629\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePathak Ray V, Ramesh SB, Rathi V (2021) Slit-lamp measurement of anterior chamber depth and its agreement with anterior segment optical coherence tomography and Lenstar LS 900 in pseudoexfoliation and normal eyes. Indian J Ophthalmol 69:2469\u0026ndash;2474\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShimizu E, Tanaka K, Nishimura H, Agata N, Tanji M, Nakayama S et al (2024) The use of artificial intelligence for estimating anterior chamber depth from slit-lamp images developed using anterior-segment optical coherence tomography. Bioengineering 11:100\u0026ndash;110\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSidek Ni, Yusof F (2021) The repeatability of smith's method in measuring anterior chamber depth. J Allied Health Sci 5:2262\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSmith RJ (1979) A new method of estimating the depth of the anterior chamber. Br J Ophthalmol 63:215\u0026ndash;220\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarrett BT, McGraw PV, Murray LA, Murgatroyd P (1996) Anterior chamber depth measurement in clinical practice. Optom Vis Sci 73:482\u0026ndash;486\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVetrugno M, Cardascia N, Cardia L (2000) Anterior chamber depth measured by two methods in myopic and hyperopic phakic IOL implant. Br J Ophthalmol 84:1113\u0026ndash;1116\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOsuobeni EP, Oduwaiye KA, Ogbuehi KC (2000) Intra-observer repeatability and inter-observer agreement of the Smith method of measuring the anterior chamber depth. Ophthalmic Physiol Opt 20:153\u0026ndash;159\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAl-Mubrad TM, Ogbuehi KC (2006) Smith-method assessment of anterior chamber depth for screening for narrow anterior chamber angles. Indian J Ophthalmol 54:165\u0026ndash;168\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDabasia PL, Edgar DF, Murdoch IE, Lawrenson JG (2015) Noncontact screening methods for the detection of narrow anterior chamber angles. Invest Ophthalmol Vis Sci 56:3929\u0026ndash;3935\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eTable 1: \u003c/span\u003e\u003c/strong\u003e\u003cspan dir=\"LTR\"\u003eDemographics data, smith ACD, Lenstar ACD, Lenstar AD, Lenstar AL, angle by AS-OCT and Lenstar AL grouping of the studied patients\u003c/span\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"602\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eN=71\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eAge (years)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e62.4 \u0026plusmn; 9.69\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 159px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSex\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMale\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e31 (43.66%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eFemale\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e40 (56.34%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 159px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSide\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eRight\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e32 (45.07%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLeft\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e39 (54.93%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD (mm)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.08 \u0026plusmn; 0.52\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar ACD (mm)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.2 \u0026plusmn; 0.49\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AD (mm)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e2.7 \u0026plusmn; 0.46\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AL (mm)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e23.3 \u0026plusmn; 1.47\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 356px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eAngle by AS-OCT (\u0026deg;)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e43.3 \u0026plusmn; 9.87\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" style=\"width: 159px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AL grouping\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eShort\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e1 (1.41%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eAverage\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e65 (91.55%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLong\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 246px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e5 (7.04%)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eData are presented as mean \u0026plusmn; SD or frequency (%) ACD: Anterior chamber depth, AD: aqueous depth, AL: axial length.\u0026nbsp;\u003c/p\u003e\n\u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eTable 2: \u003c/span\u003e\u003c/strong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD and Lenstar ACD, AD and ACD of short and average AL cases of the studied patients\u003c/span\u003e\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"691\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD (n=71)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar ACD\u003cbr\u003e\u0026nbsp; (n=71)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e(95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLower limit (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eUpper limit (95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026plusmn; SD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.08 \u0026plusmn; 0.52\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.22 \u0026plusmn; 0.49\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e-\u003c/span\u003e\u003c/strong\u003e\u003cspan dir=\"LTR\"\u003e0.13\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;(-0.19: -0.07\u003cstrong\u003e)\u003c/strong\u003e\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.63\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.73\u003c/span\u003e\u003cspan dir=\"LTR\"\u003e:-0.52)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.37\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;(0.26: 0.47)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026lt;0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eAD (n=71)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 94px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026plusmn; SD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.08 \u0026plusmn; 0.52\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e2.72 \u0026plusmn; 0.46\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 113px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.361\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.31: 0.41)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.07\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.16: 0.02)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 102px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.79\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.71: 0.89)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 67px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026lt;0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cspan dir=\"LTR\"\u003e\u003cspan lang=\"EN\" dir=\"LTR\"\u003eData are presented as mean \u0026plusmn; SD. *: significant P value \u0026le;0.05. CI: confidence interval, ACD: Anterior chamber depth, AL: Axial length.\u0026nbsp;\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eTable 3: \u003c/span\u003e\u003c/strong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD and Lenstar AD of short and average AL cases, Lenstar ACD and AD of long AL cases\u003c/span\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"690\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD\u003cbr\u003e\u0026nbsp; (n=66)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AD\u003cbr\u003e\u0026nbsp; (n=66)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026nbsp;\u003cbr\u003e\u0026nbsp;(95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLower limit\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e(95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eUpper limit\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e(95% CI)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026plusmn; SD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.06 \u0026plusmn; 0.5\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e2.69 \u0026plusmn; 0.45\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.37\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.31: 0.42)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.07\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.17: 0.02)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.81\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.71: 0.90)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026lt;0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar ACD (n=5)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026plusmn; SD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.36 \u0026plusmn; 0.64\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.54 \u0026plusmn; 0.49\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.17\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.54: 0.19)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.75\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-1.41: -0.08)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.39\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.27: 1.07)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.253\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AD\u003cbr\u003e\u0026nbsp; (n=5)\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 89px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eMean\u0026plusmn; SD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 109px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.36 \u0026plusmn; 0.64\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 97px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e3.1 \u0026plusmn; 0.49\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 114px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.27\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.057: 0.479)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e-0.07\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(-0.46: 0.32)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 96px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.60\u003c/span\u003e\u003c/p\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e(0.21: 0.99)\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 78px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e0.024*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp dir=\"LTR\"\u003e\u003cspan lang=\"EN\" dir=\"LTR\"\u003eData are presented as mean \u0026plusmn; SD. *: significant P value \u0026le;0.05. CI: confidence interval, ACD: Anterior chamber depth, AL: Axial length.\u003c/span\u003e\u003c/p\u003e\n\u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eTable 4: \u003c/span\u003e\u003c/strong\u003e\u003cspan dir=\"LTR\"\u003eCorrelation between Smith ACD and Lenstar ACD, Lenstar AD and Angle by AS-OCT of the studied patients, short, average and long AL cases\u003c/span\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"601\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 148px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar ACD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eAngle by AS-OCT\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 40px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003er\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.872\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.903\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.531\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 40px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026lt;0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 128px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026lt;0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e0.001*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" style=\"width: 601px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003elong AL cases\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" style=\"width: 148px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e\u0026nbsp;\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 217px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar ACD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 236px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eLenstar AD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" style=\"width: 108px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eSmith ACD\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 40px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003er\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 217px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.898\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 236px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cspan dir=\"LTR\"\u003e0.987\u003c/span\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 40px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003eP\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 217px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e0.038*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" style=\"width: 236px;\"\u003e\n \u003cp dir=\"LTR\"\u003e\u003cstrong\u003e\u003cspan dir=\"LTR\"\u003e0.002*\u003c/span\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 108px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 40px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 128px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 89px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 40px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd style=\"width: 197px;\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cspan dir=\"LTR\"\u003e\u003cspan lang=\"EN\" dir=\"LTR\"\u003er: Pearson correlation, *: significant P value \u0026le;0.05. ACD: Anterior chamber depth, AD: aqueous depth, AL: Axial length. \u003c/span\u003e\u003c/span\u003e\u003cspan dir=\"LTR\"\u003e\u003c/span\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Cairo University","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":"Anterior Chamber Depth, Anterior Segment OCT, Lenstar 900, Smith’s Method","lastPublishedDoi":"10.21203/rs.3.rs-9065302/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9065302/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThe anterior chamber depth (ACD) is a vital metric for evaluating angle-closure glaucoma and for strategizing cataract surgery or phakic intraocular lens (IOL) implantation. This study aimed to evaluate the mean difference in anterior chamber depth (ACD) measurements obtained by means of Smith\u0026rsquo;s technique and the Lenstar 900, as well as to ascertain its association with the anterior chamber angle (ACA) using anterior segment optical coherence tomography (AS-OCT).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis cross-sectional analytic study comprised 70 clean-corneaed people over 40 of both genders. All patients had a basic slit lamp examination of the anterior segment, including Smith's 1979 technique of measuring axial anterior chamber depth (ACD). Then, a variety of refractive states corresponding to axial length were determined by combining non-contact optical biometry (Lenstar 900) with anterior segment optical coherence tomography (AS-OCT).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eA significant difference was observed between Smith ACD (3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52) and Lenstar ACD (3.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.49) (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with a mean difference of -0.13 (-0.19: -0.07 CI), particularly evident in patients with short and average axial lengths; Smith\u0026rsquo;s technique tends to underestimate the ACD relative to Lenstar 900. This variation is insufficient to be clinically or practically important when contemplating cataract surgery or intraocular lens implantation. The estimations of ACD derived from Smith's technique show a favorable association with ACA measurements obtained using AS-OCT.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThe Smith method enables accelerated measurement of axial ACD without the need for specialized slit-lamp attachments. It is a realizable, non-invasive, and rapid technique that is appropriate for the initial assessment of patients with shallow anterior chambers.\u003c/p\u003e","manuscriptTitle":"Comparison of slit lamp based anterior chamber depth measurement with Lenstar LS 900 and its correaltion with Anterior Chamber Angle Assessed by Anterior segment OCT","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-03-10 16:48:16","doi":"10.21203/rs.3.rs-9065302/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":"ae8bce6d-0303-46db-bbd1-10f5f3c4f41f","owner":[],"postedDate":"March 10th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":64126600,"name":"Ophthalmology"}],"tags":[],"updatedAt":"2026-03-10T16:48:16+00:00","versionOfRecord":[],"versionCreatedAt":"2026-03-10 16:48:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9065302","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9065302","identity":"rs-9065302","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}