{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T19:28:37Z","timestamp":1786649317491,"version":"build-2736575974"},"reference-count":27,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"1","license":[{"start":{"date-parts":[[2024,12,23]],"date-time":"2024-12-23T00:00:00Z","timestamp":1734912000000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-sa\/4.0"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2025,1]]},"abstract":"<jats:p>\n                    The Schirmer strip measures tear volume in millimeters. A major limitation of the Schirmer strip is that it does not measure tear volume in a volumetric unit. Furthermore, the linearity range, lower limit of detection (LLOD), and lower limit of quantification (LLOQ) are not established. In this context, we developed a new filter paper based tear volume strip, which measures tear volume in microlitres (a volumetric unit), with a defined linearity range, LLOD, LLOQ, as well as inter-day and intra-day variability. We used standard Whatman filter paper no. 41, measuring 40 \u00d7 5 mm. Balanced salt solution (BSS) was used as a tear surrogate. By placing a specific volume of BSS at one marked end of the paper, we measured the distance travelled by the BSS after one minute. Different volumes of BSS (0.5, 1, 2, 4, 8, and 16 \u03bcl) were used, and the distance travelled by the BSS drop was recorded. Linearity was evaluated, and the LLOQ and LLOD were determined. Scale data were generated within the linearity range (10 replicates for each). Percentage recovery was calculated, and inter-day and intra-day variation as well as intra examiner and inter examiner coefficients of variation (CV%) were evaluated. High linearity (r\n                    <jats:sup>2<\/jats:sup>\n                    = 0.976) was observed across all the tested volumes (0.5\u201316 \u03bcl), However, linearity improved within the tested volume range of 1\u20138 \u03bcl (r\n                    <jats:sup>2<\/jats:sup>\n                    = 0.996). With an LLOD of 0.538 \u03bcl and an LLOQ of 1.63 \u03bcl, data for the scale were generated from 2\u20138 \u03bcl. Overall, volumetric recovery ranged from 97.34%\u2013104%. The intra-day CV% ranged from 4.576% (for 2 \u03bcl) to 1.911% (for 5 \u03bcl) and 1.71% (for 7 \u03bcl). The inter-day CV% ranged from 1.715 (7 \u03bcl) to 4.36% (for 2 \u03bcl). The intra examiner CV% ranged from 0.422% (for 7 \u03bcl) to 2.66% (for 2 \u03bcl). The inter examiner CV% ranged from 1.93% (7 \u03bcl) to 3.69% (for 2 \u03bcl). This new tear volume measuring tool (named SI tear strip) represents a valuable tool for the measurement of tear volume (in \u03bcl) per unit time. This tool may be very helpful for the quantitative evaluation of dry eye patients and functional assessment of lacrimal glands.\n                  <\/jats:p>","DOI":"10.4103\/ijo.ijo_162_24","type":"journal-article","created":{"date-parts":[[2024,12,23]],"date-time":"2024-12-23T03:01:02Z","timestamp":1734922862000},"page":"141-145","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":0,"title":["Development and validation of a novel tool to measure tear volume in volumetric unit (microlitre) per minute \u201cthe standard international unit (SI) tear strip\u201d"],"prefix":"10.4103","volume":"73","author":[{"given":"R","family":"Balamurugan","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, All India Institute of Medical Sciences, Mangalagiri, Andhra Pradesh, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anusuya","family":"Bhattacharyya","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, All India Institute of Medical Sciences, Guwahati, Assam, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Phulen","family":"Sarma","sequence":"additional","affiliation":[{"name":"Department of Pharmacology, All India Institute of Medical Sciences, Guwahati, Assam, India"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2024,12,23]]},"reference":[{"key":"R1-20260424","doi-asserted-by":"crossref","first-page":"772","DOI":"10.1136\/bjophthalmol-2020-318159","article-title":"Tear secretion from the lacrimal gland: Variations in normal versus dry eyes","volume":"106","author":"Singh","year":"2022","journal-title":"Br J Ophthalmol"},{"key":"R2-20260424","doi-asserted-by":"crossref","first-page":"1090","DOI":"10.4103\/IJO.IJO_2622_22","article-title":"Lacrimal and meibomian gland evaluation in dry eye disease: A mini-review","volume":"71","author":"Singh","year":"2023","journal-title":"Indian J Ophthalmol"},{"key":"R3-20260424","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1007\/BF01946264","article-title":"Studies on the physiology and pathology of tear secretion and tear removal","volume":"56","author":"Schirmer","year":"1903","journal-title":"Graefes Arhiv f\u00fcr Ophthalmologie"},{"key":"R4-20260424","doi-asserted-by":"crossref","first-page":"152","DOI":"10.1002\/j.1538-9235.1993.tb03091.x","article-title":"Schirmer test. I. A review","volume":"70","author":"Cho","year":"1993","journal-title":"Optom Vis Sci"},{"key":"R5-20260424","doi-asserted-by":"crossref","first-page":"564","DOI":"10.1001\/archopht.1962.00960020564008","article-title":"A review of the Schirmer test for tear production","volume":"67","author":"Wright","year":"1962","journal-title":"Arch Ophthalmol"},{"key":"R6-20260424","doi-asserted-by":"crossref","first-page":"224","DOI":"10.1001\/archopht.1950.00910010231004","article-title":"Influence of age and sex on flow of tears","volume":"43","author":"Henderson","year":"1950","journal-title":"Arch Ophthalmol"},{"key":"R7-20260424","doi-asserted-by":"crossref","first-page":"1383","DOI":"10.1001\/archopht.1983.01040020385009","article-title":"Schirmer\u2019s test. A closer look","volume":"101","author":"Clinch","year":"1983","journal-title":"Arch Ophthalmol"},{"key":"R8-20260424","doi-asserted-by":"crossref","first-page":"803.","DOI":"10.1007\/s42452-019-0820-x","article-title":"Calibration of filter paper for measuring total soil suction","volume":"1","author":"Pande","year":"2019","journal-title":"SN Appl Sci"},{"key":"R9-20260424","doi-asserted-by":"crossref","first-page":"563","DOI":"10.1515\/pac-2017-0410","article-title":"Mass and volume in analytical chemistry (IUPAC Technical Report)","volume":"90","author":"Cam\u00f5es","year":"2018","journal-title":"Pure Appl Chem"},{"key":"R13-20260424","doi-asserted-by":"crossref","first-page":"338","DOI":"10.1016\/j.measurement.2006.05.012","article-title":"Calibration of micropipettes: Test methods and uncertainty analysis","volume":"40","author":"Batista","year":"2007","journal-title":"Measurement"},{"key":"R14-20260424","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1007\/s00769-020-01453-5","article-title":"Evaluation of reproducibility uncertainty in micropipette calibrations for non-nominal volumes through an interlaboratory study","volume":"26","author":"Shirono","year":"2021","journal-title":"Accred Qual Assur"},{"key":"R15-20260424","doi-asserted-by":"crossref","first-page":"760","DOI":"10.1021\/ac60187a013","article-title":"Analysis of zone spreading in paper chromatography by a detection limit method","volume":"34","author":"Mallik","year":"1962","journal-title":"Anal Chem"},{"key":"R16-20260424","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1007\/s11094-021-02378-0","article-title":"Validation of chromatographic methods: Determining the limit of quantification in practice","volume":"55","author":"Epshtein","year":"2021","journal-title":"Pharm Chem J"},{"key":"R17-20260424","doi-asserted-by":"crossref","first-page":"271","DOI":"10.2967\/jnmt.112.107664","article-title":"Validation of a paper chromatographic methodology as an alternative for determination of the radiochemical purity of Na18F","volume":"40","author":"Leonardi","year":"2012","journal-title":"J Nucl Med Technol"},{"key":"R18-20260424","doi-asserted-by":"crossref","first-page":"285","DOI":"10.1097\/00003226-200305000-00001","article-title":"One-minute Schirmer test with anesthesia","volume":"22","author":"Bawazeer","year":"2003","journal-title":"Cornea"},{"issue":"Suppl 1","key":"R19-20260424","first-page":"S49","article-title":"Limit of Blank, Limit of Detection and Limit of Quantitation","volume":"29","author":"Armbruster","year":"2008","journal-title":"Clin Biochem Rev"},{"key":"R22-20260424","doi-asserted-by":"crossref","first-page":"306","DOI":"10.3341\/kjo.2022.0006","article-title":"The repeatability, reproducibility, and correlation of the schirmer test: A comparison of open versus closed eye","volume":"36","author":"Ekici","year":"2022","journal-title":"Korean J Ophthalmol"},{"key":"R23-20260424","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s12177-008-9006-2","article-title":"Quantitative assessment of tear production: A review of methods and utility in dry eye drug discovery","volume":"1","author":"Senchyna","year":"2008","journal-title":"J Ocul Biol Dis Infor"},{"key":"R24-20260424","first-page":"15.","article-title":"The role of different tear volume detection methods in the evaluation and diagnosis of mild dry eye disease","volume":"11","author":"Wang","year":"2022","journal-title":"Transl Vis Sci Technol"},{"key":"R25-20260424","doi-asserted-by":"crossref","first-page":"826530","DOI":"10.3389\/fmed.2021.826530","article-title":"Advances in dry eye disease examination techniques","volume":"8","author":"Wu","year":"2022","journal-title":"Front Med"},{"key":"R26-20260424","first-page":"264","article-title":"Determination of tear volume and tear flow","volume":"5","author":"Mishima","year":"1966","journal-title":"Invest Ophthalmol Vis Sci"},{"key":"R27-20260424","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1167\/tvst.8.6.34","article-title":"Assessment of corneal fluorescein staining in different dry eye subtypes using digital image analysis","volume":"8","author":"Pellegrini","year":"2019","journal-title":"Transl Vis Sci Technol"},{"key":"R28-20260424","doi-asserted-by":"crossref","first-page":"27.","DOI":"10.1186\/1752-1947-4-27","article-title":"Anaphylactic response to topical fluorescein 2% eye drops: A case report","volume":"4","author":"Shahid","year":"2010","journal-title":"J Med Case Rep"},{"key":"R29-20260424","article-title":"Tear meniscus height agreement and reproducibility between two corneal topographers and spectral-domain optical coherence tomography","author":"Soares","year":"2024","journal-title":"Clin Exp Optom"},{"key":"R30-20260424","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/j.ajo.2013.09.024","article-title":"Tear meniscus dimensions in tear dysfunction and their correlation with clinical parameters","volume":"157","author":"Tung","year":"2014","journal-title":"Am J Ophthalmol"},{"key":"R31-20260424","doi-asserted-by":"crossref","first-page":"795","DOI":"10.1016\/j.ajo.2007.12.035","article-title":"Correlations among upper and lower tear menisci, non-invasive tear break-up time and Schirmer\u2019s test","volume":"145","author":"Wang","year":"2008","journal-title":"Am J Ophthalmol"},{"key":"R32-20260424","doi-asserted-by":"crossref","first-page":"272","DOI":"10.1097\/00003226-200404000-00010","article-title":"The repeatability of clinical measurements of dry eye","volume":"23","author":"Nichols","year":"2004","journal-title":"Cornea"}],"container-title":["Indian Journal of Ophthalmology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.4103\/IJO.IJO_162_24","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T18:52:19Z","timestamp":1786647139000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.4103\/IJO.IJO_162_24"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,12,23]]},"references-count":27,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2025]]}},"URL":"https:\/\/doi.org\/10.4103\/ijo.ijo_162_24","relation":{},"ISSN":["0301-4738","1998-3689"],"issn-type":[{"value":"0301-4738","type":"print"},{"value":"1998-3689","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,12,23]]},"assertion":[{"value":"2024-01-16","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-08-28","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}