{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,9]],"date-time":"2026-03-09T23:16:33Z","timestamp":1773098193360,"version":"3.50.1"},"reference-count":12,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2014,6,2]],"date-time":"2014-06-02T00:00:00Z","timestamp":1401667200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Acta Ophthalmologica"],"published-print":{"date-parts":[[2014,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec><jats:title>Purpose<\/jats:title><jats:p>To investigate the changes in the tear flow velocities caused by ageing.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Ninety\u2010nine subjects (41 men, mean age 48.3\u00a0\u00b1\u00a020.7\u00a0years) were recruited from the Department of Ophthalmology of the Ehime University Hospital. None of the subjects had serious abnormalities of the external surface of the eye. The Krehbiel flow of tears was determined by 40\u2010<jats:italic>\u03bc<\/jats:italic>m polymethylmethacrylate (<jats:styled-content style=\"fixed-case\">PMMA<\/jats:styled-content>) beads suspended in a fluorescein sodium solution (<jats:styled-content style=\"fixed-case\">PPF<\/jats:styled-content>). The movement of the beads was video recorded through a slit\u2010lamp during normal blinking. The flow of the beads was determined with a Motion <jats:sc>analyzer<\/jats:sc><jats:sup>\u00ae<\/jats:sup>software (<jats:styled-content style=\"fixed-case\">KEYENCE<\/jats:styled-content> Co., Osaka, Japan). The velocity of the beads in young age, 20\u201340\u00a0years, middle age, 41\u201360\u00a0years and old age, \u226561\u00a0years, groups was determined.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>The equation describing the velocity (mm\/second) of the <jats:styled-content style=\"fixed-case\">PMMA<\/jats:styled-content> particles as a function of age in the lower tear meniscus measured in the direction of the lacrimal punctum was <jats:italic>Y<\/jats:italic>\u00a0=\u00a02.49\u22120.04<jats:italic>X<\/jats:italic>, where <jats:italic>Y<\/jats:italic>\u00a0=\u00a0velocity and <jats:italic>X<\/jats:italic>\u00a0=\u00a0age (<jats:italic>r<\/jats:italic><jats:sup>2<\/jats:sup>\u00a0=\u00a00.214; p<jats:italic>\u00a0<\/jats:italic>&lt;<jats:italic>\u00a0<\/jats:italic>0.0001). For the upper meniscus, the equation was <jats:italic>Y<\/jats:italic>\u00a0=\u00a04.83\u22120.05<jats:italic>X<\/jats:italic> (<jats:italic>r<\/jats:italic><jats:sup>2<\/jats:sup>\u00a0=\u00a00.195, p<jats:italic>\u00a0<\/jats:italic>&lt;<jats:italic>\u00a0<\/jats:italic>0.0001). The average velocity was 0.70\u00a0\u00b1\u00a01.66\u00a0mm\/second in the lower and 2.16\u00a0\u00b1\u00a01.93\u00a0mm\/second in the upper tear meniscus (p<jats:italic>\u00a0<\/jats:italic>&lt;<jats:italic>\u00a0<\/jats:italic>0.0001). The particle velocity decreased significantly with increasing age, but no significant difference between the male and female groups except for the lower tear meniscus when all subjects were analysed.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>The <jats:styled-content style=\"fixed-case\">PPF<\/jats:styled-content> technique is a simple method of examining Krehbiel flow of tears and may be used for evaluating functional nasolacrimal duct obstruction quantitatively.<\/jats:p><\/jats:sec>","DOI":"10.1111\/aos.12444","type":"journal-article","created":{"date-parts":[[2014,6,3]],"date-time":"2014-06-03T01:57:11Z","timestamp":1401760631000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["New method for viewing Krehbiel flow by polymethylmethacrylate particles suspended in fluorescein solution"],"prefix":"10.1111","volume":"92","author":[{"given":"Masahiko","family":"Yamaguchi","sequence":"first","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kiyohiko","family":"Ohta","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Atsushi","family":"Shiraishi","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuri","family":"Sakane","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaodong","family":"Zheng","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomoyuki","family":"Kamao","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yasuaki","family":"Yamamoto","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yasushi","family":"Inoue","sequence":"additional","affiliation":[{"name":"Inoue Eye Clinic Tamano\u2010shi Okayama Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuichi","family":"Ohashi","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology Ehime University School of Medicine Ehime Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2014,6,2]]},"reference":[{"key":"e_1_2_5_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0161-6420(94)31293-0"},{"key":"e_1_2_5_3_1","first-page":"506","article-title":"The cure of epiphora due to canalicular disorders, trauma and surgical failures on the lacrimal passages","volume":"66","author":"Jones LT","year":"1962","journal-title":"Trans Am Acad Ophthalmol Otolaryngol"},{"key":"e_1_2_5_4_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0161-6420(80)35143-9"},{"key":"e_1_2_5_5_1","doi-asserted-by":"publisher","DOI":"10.1097\/00004397-197301310-00009"},{"key":"e_1_2_5_6_1","first-page":"651","article-title":"The carbon particles test and the tear flow","volume":"30","author":"Nagashima K","year":"1976","journal-title":"Rinsho 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