{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T03:02:59Z","timestamp":1787022179228,"version":"build-2736575974"},"reference-count":34,"publisher":"Public Library of Science (PLoS)","issue":"7","license":[{"start":{"date-parts":[[2025,7,23]],"date-time":"2025-07-23T00:00:00Z","timestamp":1753228800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:sec id=\"sec009\">\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>The purpose of this study was to investigate the repeatability of corneal power and thickness measures in a large patient cohort.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec010\">\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this retrospective non-randomised cross sectional single-centre study we evaluated a dataset containing 900 Casia2 anterior segment tomography measurements from 300 eyes from 300 patients (3 repeat measurements each) taken prior to cataract surgery. Only complete measurements marked as \u2018Successful\u2019 and with a sequence of 3 measurements for each eye performed on the same day were considered. Keratometry (K), corneal back surface (P) and RealPower (R) were each decomposed into power vector components SEQ\/C0\/C45. The mean (MEAN) and standard deviations (SD) for each sequence of measurements were derived and analysed.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec011\">\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>For K the MEAN and SD SEQ\/C0\/C45 were 43.77\/0.17\/-0.02 D and 0.12\/0.18\/0.18 D, for P MEAN and SD were \u22126.13\/-0.25\/0.00 D and 0.01\/0.03\/0.02 D, and for R MEAN and SD were 42.77\/-0.06\/-0.03 D and 0.13\/0.19\/0.19 D. For K and R 20%\/42%\/41% and 24%\/45%\/44% of repeat measurements respectively fell outside limits of \u00b11\/8 D. The cornea was slightly thicker at the apex than at the thinnest point (544.6 vs. 536.2 \u00b5m) and SD was 4.3 vs. 3.9 \u00b5m. Keratometry underestimates against-the-rule corneal astigmatism by around 0.23 D.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec id=\"sec012\">\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The variation of corneal power with repeat measurements is in a range of \u00b11\/8 D for keratometric and RealPower SEQ. Where the Casia2 is used for lens power calculation, repeat measurements could help to improve the refractive outcome.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1371\/journal.pone.0328894","type":"journal-article","created":{"date-parts":[[2025,7,23]],"date-time":"2025-07-23T17:26:03Z","timestamp":1753291563000},"page":"e0328894","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":3,"title":["Repeatability of corneal measurements from the Casia2 anterior segment tomographer in a cataractous population"],"prefix":"10.1371","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9175-6177","authenticated-orcid":true,"given":"Achim","family":"Langenbucher","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N\u00f3ra","family":"Szentm\u00e1ry","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0779-7449","authenticated-orcid":true,"given":"Alan","family":"Cayless","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Schartm\u00fcller","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marcus","family":"Lisy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rupert","family":"Menapace","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jascha","family":"Wendelstein","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christina","family":"Leydolt","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,7,23]]},"reference":[{"issue":"6","key":"pone.0328894.ref001","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1136\/bjo-2023-323921","article-title":"Prediction of spectacle refraction uncertainties with discrete IOL power steps and manufacturing tolerances according to ISO using a Monte Carlo model","volume":"108","author":"A Langenbucher","year":"2024","journal-title":"Br J Ophthalmol"},{"issue":"2","key":"pone.0328894.ref002","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1111\/ceo.14474","article-title":"Prediction of refraction error after toric lens implantation with biometric input data uncertainties and power labelling tolerances: Response","volume":"53","author":"A Langenbucher","year":"2025","journal-title":"Clin Exp Ophthalmol"},{"issue":"1","key":"pone.0328894.ref003","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0313574","article-title":"Evaluation of keratometric and total corneal astigmatism measurements from optical biometers and anterior segment tomographers and mapping to reconstructed corneal astigmatism vector components","volume":"20","author":"A Langenbucher","year":"2025","journal-title":"PLoS One"},{"issue":"1","key":"pone.0328894.ref004","doi-asserted-by":"crossref","DOI":"10.1111\/aos.16742","article-title":"The Homburg-Adelaide toric IOL nomogram: How to predict corneal power vectors from preoperative IOLMaster 700 keratometry and total corneal power in toric IOL implantation","volume":"103","author":"A Langenbucher","year":"2025","journal-title":"Acta Ophthalmol"},{"issue":"6","key":"pone.0328894.ref005","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1111\/ceo.14387","article-title":"Evaluating keratometry and corneal astigmatism data from biometers and anterior segment tomographers and mapping to reconstructed corneal astigmatism","volume":"52","author":"A Langenbucher","year":"2024","journal-title":"Clin Exp Ophthalmol"},{"issue":"14","key":"pone.0328894.ref006","doi-asserted-by":"crossref","first-page":"857","DOI":"10.21037\/atm-20-187","article-title":"Comparison of a new anterior segment optical coherence tomography and Oculus Pentacam for measurement of anterior chamber depth and corneal thickness","volume":"8","author":"X Li","year":"2020","journal-title":"Ann Transl Med"},{"key":"pone.0328894.ref007","doi-asserted-by":"crossref","first-page":"3584137","DOI":"10.1155\/2016\/3584137","article-title":"Autorefraction, retinoscopy, Javal\u2019s Rule, and Grosvenor\u2019s Modified Javal\u2019s Rule: the best predictor of refractive astigmatism","volume":"2016","author":"K Asiedu","year":"2016","journal-title":"J Ophthalmol"},{"issue":"1","key":"pone.0328894.ref008","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1097\/00006324-199401000-00005","article-title":"Accuracy of Javal\u2019s rule in the determination of spectacle astigmatism","volume":"71","author":"M Elliott","year":"1994","journal-title":"Optom Vis Sci"},{"issue":"4","key":"pone.0328894.ref009","doi-asserted-by":"crossref","first-page":"292","DOI":"10.1097\/00006324-198804000-00009","article-title":"Predicting refractive astigmatism: a suggested simplification of Javal\u2019s rule","volume":"65","author":"T Grosvenor","year":"1988","journal-title":"Am J Optom Physiol Opt"},{"issue":"5","key":"pone.0328894.ref010","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0268856","article-title":"Agreement of total corneal power between 2 swept-source optical coherence tomography and Scheimpflug tomography in normal and keratoconic patients","volume":"17","author":"R Asawaworarit","year":"2022","journal-title":"PLoS One"},{"issue":"10","key":"pone.0328894.ref011","doi-asserted-by":"crossref","first-page":"1196","DOI":"10.1097\/OPX.0000000000001785","article-title":"Agreement and repeatability of corneal thickness and radius among three different corneal measurement devices","volume":"98","author":"S Biswas","year":"2021","journal-title":"Optom Vis Sci"},{"issue":"1","key":"pone.0328894.ref012","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1097\/ICL.0000000000000603","article-title":"Repeatability and agreement of a swept-source optical coherence tomography-based biometer IOLMaster 700 versus a scheimpflug imaging-based biometer AL-Scan in cataract patients","volume":"46","author":"TCY Chan","year":"2020","journal-title":"Eye Contact Lens"},{"issue":"1","key":"pone.0328894.ref013","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1186\/s12886-024-03696-z","article-title":"Repeatability and agreement of two swept-source optical coherence tomographers and scheimpflug imaging for measurements of corneal curvature","volume":"24","author":"S Cheng","year":"2024","journal-title":"BMC Ophthalmol"},{"issue":"7","key":"pone.0328894.ref014","doi-asserted-by":"crossref","first-page":"602","DOI":"10.1097\/IJG.0000000000001989","article-title":"Repeatability and agreement of two swept-source optical coherence tomographers for anterior segment parameter measurements","volume":"31","author":"S-M Cheng","year":"2022","journal-title":"J Glaucoma"},{"issue":"7","key":"pone.0328894.ref015","doi-asserted-by":"crossref","first-page":"2271","DOI":"10.1007\/s00417-022-05579-9","article-title":"Repeatability of a new swept-source optical coherence tomographer and agreement with other three optical biometers","volume":"260","author":"S-M Cheng","year":"2022","journal-title":"Graefes Arch Clin Exp Ophthalmol"},{"issue":"5","key":"pone.0328894.ref016","doi-asserted-by":"crossref","first-page":"1094","DOI":"10.3390\/jcm10051094","article-title":"Swept source optical coherence tomography analysis of the selected eye\u2019s anterior segment parameters","volume":"10","author":"M Dembski","year":"2021","journal-title":"J Clin Med"},{"issue":"8","key":"pone.0328894.ref017","doi-asserted-by":"crossref","first-page":"800","DOI":"10.1111\/ceo.14423","article-title":"Repeatability and agreement of total corneal astigmatism measured in keratoconic eyes using four current devices","volume":"52","author":"Y Feng","year":"2024","journal-title":"Clin Exp Ophthalmol"},{"issue":"2","key":"pone.0328894.ref018","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1007\/s00417-016-3555-z","article-title":"Evaluation of the repeatability of a swept-source ocular biometer for measuring ocular biometric parameters","volume":"255","author":"T Ferrer-Blasco","year":"2017","journal-title":"Graefes Arch Clin Exp Ophthalmol"},{"issue":"8","key":"pone.0328894.ref019","doi-asserted-by":"crossref","first-page":"1244","DOI":"10.18240\/ijo.2020.08.10","article-title":"Agreement of corneal curvature and central corneal thickness obtained from a swept-source OCT and Pentacam in ectopia lentis patients","volume":"13","author":"G-M Jin","year":"2020","journal-title":"Int J Ophthalmol"},{"key":"pone.0328894.ref020","doi-asserted-by":"crossref","first-page":"6181405","DOI":"10.1155\/2017\/6181405","article-title":"Repeatability and agreement of central corneal thickness and keratometry measurements between four different devices","volume":"2017","author":"L Kiraly","year":"2017","journal-title":"J Ophthalmol"},{"issue":"2","key":"pone.0328894.ref021","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1097\/j.jcrs.0000000000000731","article-title":"Agreement between swept-source optical biometry and Scheimpflug-based topography measurements of posterior corneal curvature","volume":"48","author":"B Kose","year":"2022","journal-title":"J Cataract Refract Surg"},{"issue":"1","key":"pone.0328894.ref022","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1080\/17434440.2019.1557517","article-title":"Repeatability assessment of biometric measurements with different refractive states and age using a swept-source biometer","volume":"16","author":"N Mart\u00ednez-Albert","year":"2019","journal-title":"Expert Rev Med Devices"},{"issue":"4","key":"pone.0328894.ref023","doi-asserted-by":"crossref","first-page":"860","DOI":"10.1111\/opo.13148","article-title":"Feasibility and repeatability of ocular biometry measured with IOLMaster 700 in a large population-based study","volume":"43","author":"R Michael","year":"2023","journal-title":"Ophthalmic Physiol Opt"},{"issue":"1","key":"pone.0328894.ref024","doi-asserted-by":"crossref","first-page":"182","DOI":"10.1186\/s12886-024-03448-z","article-title":"Repeatability assessment of anterior segment measurements in myopic patients using an anterior segment OCT with placido corneal topography and agreement with a swept-source OCT","volume":"24","author":"H Wang","year":"2024","journal-title":"BMC Ophthalmol"},{"issue":"7","key":"pone.0328894.ref025","doi-asserted-by":"crossref","first-page":"818","DOI":"10.1097\/ICO.0000000000002280","article-title":"Comparison of a new swept-source anterior segment optical coherence tomography and a scheimpflug camera for measurement of corneal curvature","volume":"39","author":"T Zhang","year":"2020","journal-title":"Cornea"},{"issue":"2","key":"pone.0328894.ref026","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1097\/ICL.0000000000000552","article-title":"An evaluation of the IOLMaster 700","volume":"45","author":"MA Bullimore","year":"2019","journal-title":"Eye Contact Lens"},{"issue":"12","key":"pone.0328894.ref027","doi-asserted-by":"crossref","first-page":"1065","DOI":"10.1080\/10629360600878449","article-title":"On tests for multivariate normality and associated simulation studies","volume":"77","author":"PJ Farrell","year":"2007","journal-title":"J Statist Computation Simulation"},{"issue":"3","key":"pone.0328894.ref028","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1007\/BF01891203","article-title":"Approximating the Shapiro-Wilk W-test for non-normality","volume":"2","author":"P Royston","year":"1992","journal-title":"Stat Comput"},{"key":"pone.0328894.ref029","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1016\/j.comgeo.2007.10.004","article-title":"An optimal extension of the centerpoint theorem","volume":"42","author":"NH Mustafa","year":"2009","journal-title":"Computational Geometry"},{"issue":"3","key":"pone.0328894.ref030","first-page":"263","article-title":"A survey of multidimensional medians","volume":"58","author":"CG Small","year":"1990","journal-title":"Int Statist Rev \/ Revue Internationale de Statistique"},{"issue":"1","key":"pone.0328894.ref031","doi-asserted-by":"crossref","first-page":"31","DOI":"10.2307\/3314859","article-title":"Measures of centrality for multivariate and directional distributions","volume":"15","author":"CG Small","year":"1987","journal-title":"Can J Statistics"},{"key":"pone.0328894.ref032","first-page":"199","article-title":"The convex-hull-stripping median approximates affine curvature motion","author":"M Welk","year":"2019","journal-title":"Lecture Notes in Computer Science. Springer International Publishing"},{"issue":"4","key":"pone.0328894.ref033","first-page":"197","article-title":"Fourier analysis as a mathematical model for evaluating and presenting postoperative corneal topography data after non-mechanical perforating keratoplasty","volume":"210","author":"A Langenbucher","year":"1997","journal-title":"Klin Monbl Augenheilkd"},{"issue":"2","key":"pone.0328894.ref034","doi-asserted-by":"crossref","first-page":"505","DOI":"10.1007\/s00417-023-06186-y","article-title":"Technical variability of cornea parameters derived from anterior segment OCT fitted with Fringe Zernike polynomials","volume":"262","author":"A Langenbucher","year":"2024","journal-title":"Graefes Arch Clin Exp Ophthalmol"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0328894","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,7,23]],"date-time":"2025-07-23T17:26:08Z","timestamp":1753291568000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0328894"}},"subtitle":[],"editor":[{"given":"Clara","family":"Mart\u00ednez P\u00e9rez","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2025,7,23]]},"references-count":34,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2025,7,23]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0328894","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,7,23]]}}}