{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,31]],"date-time":"2026-03-31T11:17:09Z","timestamp":1774955829905,"version":"3.50.1"},"reference-count":53,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2013,4,1]],"date-time":"2013-04-01T00:00:00Z","timestamp":1364774400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2013,4,1]],"date-time":"2013-04-01T00:00:00Z","timestamp":1364774400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"funder":[{"DOI":"10.13039\/100003760","name":"Foundation for Iranian Studies","doi-asserted-by":"publisher","award":["PI10\/01843"],"award-info":[{"award-number":["PI10\/01843"]}],"id":[{"id":"10.13039\/100003760","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["OVS"],"published-print":{"date-parts":[[2013,4]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>To assess in a sample of normal, keratoconic, and keratoconus (KC) suspect eyes the performance of a set of new topographic indices computed directly from the digitized images of the Placido rings.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>This comparative study was composed of a total of 124 eyes of 106 patients from the ophthalmic clinics Vissum Alicante and Vissum Almer\u00eda (Spain) divided into three groups: control group (50 eyes), KC group (50 eyes), and KC suspect group (24 eyes). In all cases, a comprehensive examination was performed, including the corneal topography with a Placido\u2010based CSO topography system. Clinical outcomes were compared among groups, along with the discriminating performance of the proposed irregularity indices.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Significant differences at level 0.05 were found on the values of the indices among groups by means of Mann\u2010Whitney\u2010Wilcoxon nonparametric test and Fisher exact test. Additional statistical methods, such as receiver operating characteristic analysis and K\u2010fold cross validation, confirmed the capability of the indices to discriminate between the three groups.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Direct analysis of the digitized images of the Placido mires projected on the cornea is a valid and effective tool for detection of corneal irregularities. Although based only on the data from the anterior surface of the cornea, the new indices performed well even when applied to the KC suspect eyes. They have the advantage of simplicity of calculation combined with high sensitivity in corneal irregularity detection and thus can be used as supplementary criteria for diagnosing and grading KC that can be added to the current keratometric classifications.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1097\/opx.0b013e3182843f2a","type":"journal-article","created":{"date-parts":[[2013,2,1]],"date-time":"2013-02-01T12:26:17Z","timestamp":1359721577000},"page":"335-343","source":"Crossref","is-referenced-by-count":25,"title":["Screening Subclinical Keratoconus With Placido\u2010Based Corneal Indices"],"prefix":"10.1002","volume":"90","author":[{"given":"Dar\u00edo","family":"Ramos\u2010L\u00f3pez","sequence":"first","affiliation":[{"name":"Department of Mathematics University of Almer\u00eda Almer\u00eda Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrei","family":"Mart\u00ednez\u2010Finkelshtein","sequence":"additional","affiliation":[{"name":"Department of Mathematics University of Almer\u00eda Almer\u00eda Spain"},{"name":"Institute Carlos I of Theoretical and Computational Physics Granada University Granada Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gracia M.","family":"Castro\u2010Luna","sequence":"additional","affiliation":[{"name":"VISSUM Corporation Almer\u00eda Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Neus","family":"Burguera\u2010Gimenez","sequence":"additional","affiliation":[{"name":"Division of Ophthalmology Universidad Miguel Hern\u00e1ndez Alicante Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Alfredo","family":"Vega\u2010Estrada","sequence":"additional","affiliation":[{"name":"Division of Ophthalmology Universidad Miguel Hern\u00e1ndez Alicante Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David","family":"Pi\u00f1ero","sequence":"additional","affiliation":[{"name":"Departamento de \u00d3ptica Farmacolog\u00eda y Anatom\u00eda Universidad de Alicante Alicante Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jorge L.","family":"Ali\u00f3","sequence":"additional","affiliation":[{"name":"VISSUM Corporation Alicante Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2013,4,1]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1016\/S0039-6257(97)00119-7","article-title":"Keratoconus","volume":"42","author":"Rabinowitz YS","year":"1998","journal-title":"Surv Ophthalmol"},{"key":"e_1_2_7_3_1","doi-asserted-by":"crossref","first-page":"1948","DOI":"10.1167\/iovs.09-4177","article-title":"Corneal biomechanics, refraction, and corneal aberrometry in keratoconus: an integrated study","volume":"51","author":"Pi\u00f1ero DP","year":"2010","journal-title":"Invest Ophthalmol Vis Sci"},{"key":"e_1_2_7_4_1","doi-asserted-by":"crossref","first-page":"3026","DOI":"10.1167\/iovs.04-0694","article-title":"Assessment of the biomechanical properties of the cornea with the ocular response analyzer in normal and keratoconic eyes","volume":"48","author":"Shah S","year":"2007","journal-title":"Invest Ophthalmol Vis Sci"},{"key":"e_1_2_7_5_1","doi-asserted-by":"crossref","first-page":"1371","DOI":"10.1016\/j.jcrs.2007.04.021","article-title":"Corneal biomechanical properties in normal, post\u2010laser in situ keratomileusis, and keratoconic eyes","volume":"33","author":"Ortiz D","year":"2007","journal-title":"J Cataract Refract Surg"},{"key":"e_1_2_7_6_1","doi-asserted-by":"crossref","first-page":"349","DOI":"10.1001\/archopht.1991.01080030051037","article-title":"Quantitative descriptors of corneal topography. 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