{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T16:21:26Z","timestamp":1787761286211,"version":"build-2784847793"},"reference-count":21,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"9","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2019,9]]},"abstract":"<jats:sec>\n                    <jats:title>Purpose:<\/jats:title>\n                    <jats:p>Compare the agreement between the finally fitted back optic zone radius (BOZR) of a spherical gas permeable (GP) contact lense (CL) with those proposed by different guidelines currently available to fit GP CLs in keratoconus.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>\n                      The BOZR fitted in 81 keratoconus eyes (46 patients) were recorded and compared with the BOZR calculated with ten different guidelines (identified after a literature review) proposed to calculate the first diagnostic lens BOZR to be fitted in keratoconus. Arithmetic and absolute mean difference between both BOZR were calculated (paired\n                      <jats:italic toggle=\"yes\">t<\/jats:italic>\n                      -test). The success rate of each guideline (difference between both BOZR \u22640.05 mm) was calculated for different keratoconus stages (Amsler\u2013Krumeich classification). Agreement between BOZR was evaluated using Bland-Altman analysis.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      The BOZR proposed by all guidelines correlated with the final BOZR that was fitted (R\n                      <jats:sup>2<\/jats:sup>\n                      &gt; 0.71;\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.01). A statistically significant difference was found between the BOZR suggested by all guidelines and the BOZR that was prescribed (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      &lt; 0.05), except for three Guidelines (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      \u2265 0.11). CALCULENS.com presented the best agreement (mean difference of 0.00 \u00b1 0.12 mm), and 50.6% of cases showed \u22640.05 mm of difference with the BOZR that was fitted. However, the worst guideline showed an agreement of \u22120.38 \u00b1 0.22 mm, and just 3.8% of cases had \u22640.05 mm of difference with the final fitted BOZR.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>BOZR calculated with most of the analyzed guidelines shows statistical differences with final fitted BOZR, suggesting a lack of clinical validation of these guidelines. The selection of the BOZR with CALCULENS.com could provide a better starting point for spherical GP CL fitting in keratoconus eyes.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/ijo.ijo_1538_18","type":"journal-article","created":{"date-parts":[[2019,8,26]],"date-time":"2019-08-26T03:09:46Z","timestamp":1566788986000},"page":"1410-1416","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":5,"title":["Gas permeable contact lens fitting in keratoconus: Comparison of different guidelines to back optic zone radius calculations"],"prefix":"10.4103","volume":"67","author":[{"given":"Sara","family":"Ortiz-Toquero","sequence":"first","affiliation":[{"name":"Universidad de Valladolid, Departamento de F\u00edsica Te\u00f3rica, At\u00f3mica y \u00d3ptica, Valladolid, Espa\u00f1a"},{"name":"Universidad de Valladolid, Instituto Universitario de Oftalmobiolog\u00eda Aplicada (IOBA), Valladolid, Espa\u00f1a"},{"name":"Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guadalupe","family":"Rodriguez","sequence":"additional","affiliation":[{"name":"Universidad de Valladolid, Departamento de F\u00edsica Te\u00f3rica, At\u00f3mica y \u00d3ptica, Valladolid, Espa\u00f1a"},{"name":"Universidad de Valladolid, Instituto Universitario de Oftalmobiolog\u00eda Aplicada (IOBA), Valladolid, Espa\u00f1a"},{"name":"Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Victoria","family":"de Juan","sequence":"additional","affiliation":[{"name":"Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid, Spain"},{"name":"Department of Ophthalmology, Ram\u00f3n y Cajal University Hospital, Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raul","family":"Martin","sequence":"additional","affiliation":[{"name":"Universidad de Valladolid, Departamento de F\u00edsica Te\u00f3rica, At\u00f3mica y \u00d3ptica, Valladolid, Espa\u00f1a"},{"name":"Universidad de Valladolid, Instituto Universitario de Oftalmobiolog\u00eda Aplicada (IOBA), Valladolid, Espa\u00f1a"},{"name":"Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid, Spain"},{"name":"Faculty of Health and Human Sciences, Plymouth University, Plymouth, United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"R1-20251013","doi-asserted-by":"crossref","first-page":"1510","DOI":"10.1097\/ICO.0b013e318211401f","article-title":"Contact lenses in the management of keratoconus","volume":"30","author":"Barnett","year":"2011","journal-title":"Cornea"},{"key":"R2-20251013","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1111\/cxo.12300","article-title":"Contact lens management of keratoconus","volume":"98","author":"Downie","year":"2015","journal-title":"Clin Exp Optom"},{"key":"R4-20251013","doi-asserted-by":"crossref","first-page":"1043","DOI":"10.1007\/s11136-015-1117-1","article-title":"The influence of the refractive correction on the vision-related quality of life in keratoconus patients","volume":"25","author":"Ortiz-Toquero","year":"2016","journal-title":"Qual Life Res"},{"key":"R5-20251013","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1016\/j.clae.2010.04.006","article-title":"Keratoconus: A review. 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