{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T21:39:05Z","timestamp":1781559545218,"version":"3.54.5"},"reference-count":44,"publisher":"Public Library of Science (PLoS)","issue":"12","license":[{"start":{"date-parts":[[2020,12,3]],"date-time":"2020-12-03T00:00:00Z","timestamp":1606953600000},"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=\"sec001\">\n<jats:title>Background\/Aims<\/jats:title>\n<jats:p>Smartphone use has become an indispensable part of our daily life. The handy design and powerful processor allow smartphone users to perform diversified tasks even when walking. This study aimed to investigate and compare the optical aftereffect and vergence adaptation of using a smartphone while walking and sitting.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods<\/jats:title>\n<jats:p>Twenty-nine young healthy adults (aged 19 to 24 years old) with normal binocular and accommodative functions were recruited. Participants were asked to watch a movie for 30 minutes using a smartphone while either walking on a treadmill or sitting on a chair. Corneal aberrations and near heterophoria were measured before and after smartphone use by a corneal topographer and modified Thorington heterophoria test, respectively.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Results<\/jats:title>\n<jats:p>Using the smartphone while walking induced a change in corneal H\/V astigmatism, becoming 0.11\u00b10.03 \u03bcm less negative (two-way ANOVA repeated measures, Bonferroni post-hoc test, p = 0.001). This optical aftereffect was significantly higher than after smartphone use while sitting by 0.10\u00b10.03 \u03bcm (paired t-test, p = 0.003). Although smartphone use did not result in a significant change in near heterophoria (Bonferroni post-hoc test, p &gt; 0.15), the vergence adaptation showed relatively more eso- or less exo-deviation by 0.79\u00b10.36<jats:sup>\u0394<\/jats:sup> in the walking than the sitting condition (paired t-test, p = 0.037).<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec004\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>Eyecare practitioners should be cautious of the potential optical after effect and vergence adaptation after prolonged smartphone usage.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0243072","type":"journal-article","created":{"date-parts":[[2020,12,3]],"date-time":"2020-12-03T18:30:33Z","timestamp":1607020233000},"page":"e0243072","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":17,"title":["Changes in corneal astigmatism and near heterophoria after smartphone use while walking and sitting"],"prefix":"10.1371","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9588-2891","authenticated-orcid":true,"given":"Tsz Wing","family":"Leung","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chui-Ting","family":"Chan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chi-Hin","family":"Lam","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuk-Kwan","family":"Tong","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5177-129X","authenticated-orcid":true,"given":"Chea-Su","family":"Kee","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2020,12,3]]},"reference":[{"key":"pone.0243072.ref001","author":"S O'Dea","year":"2020","journal-title":"Smartphone users worldwide 2016\u20132021"},{"key":"pone.0243072.ref002","unstructured":"Census and Statistics Department Hong Kong Special Administrative Region. 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