{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,6]],"date-time":"2026-02-06T23:25:13Z","timestamp":1770420313371,"version":"3.49.0"},"reference-count":23,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2022,5,8]],"date-time":"2022-05-08T00:00:00Z","timestamp":1651968000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2022,5,8]],"date-time":"2022-05-08T00:00:00Z","timestamp":1651968000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Eye and Vis"],"published-print":{"date-parts":[[2022,12]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:sec>\n                <jats:title>Background<\/jats:title>\n                <jats:p>Measuring quality of life is of importance in keratoconus. So far, the Keratoconus End-Points Assessment Questionnaire (KEPAQ) is the only keratoconus-specific scale to measure emotional well-being along with functional compromise in this population. Nevertheless, there is still a lack of clarity and standardization as to how KEPAQ scores should be computed and reported. There are also no guidelines for interpretation of classification of quality of life when using this instrument. The purpose of this study is to provide a specific framework on how to grade and classify keratoconus by using the KEPAQ and propose an extension of current classification to encompass subjective compromise.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Methods<\/jats:title>\n                <jats:p>A group of patients with a confirmed diagnosis of keratoconus underwent application of the KEPAQ. First, a Rasch modeling was performed to evaluate the psychometric characteristics of both sub-scales of the instrument. Then, a linear transformation was performed to turn data into a more relatable scale ranging from 0 to 100. Finally, by using Tukey\u2019s Hinges, scores of the KEPAQ were divided in a 1-to-4 scale, allowing for an easy E&amp;F classification system.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Results<\/jats:title>\n                <jats:p>A total of 386 applications of the KEPAQ were included. Analysis provided evidence of the KEPAQ being unidimensional, well-fitted to the Rasch Model, and provided adequate interval-level scores. Linear transformation resulted in a user-friendly final score ranging from 0 to 100, where a higher score translates to having a better quality of life. Two methods of easily computing final score, one by hand and the other\u00a0one by an Excel file, were constructed. An E&amp;F 1-to-4 classification was proposed, which may work well with the current ABCD classification of keratoconus.<\/jats:p>\n              <\/jats:sec><jats:sec>\n                <jats:title>Conclusions<\/jats:title>\n                <jats:p>The KEPAQ is a psychometrically robust scale, which confidently measures both emotional-related and functional-related quality of life in patients with keratoconus. It can be easily computed, and the results are interpretable and classified in a manner similar to that used in the ABCD keratoconus classification, by adding letters \u2018E\u2019 for emotional and \u2018F\u2019 for functional compromise.<\/jats:p>\n              <\/jats:sec>","DOI":"10.1186\/s40662-022-00288-0","type":"journal-article","created":{"date-parts":[[2022,5,8]],"date-time":"2022-05-08T00:04:02Z","timestamp":1651968242000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Standardizing the measurement and classification of quality of life using the Keratoconus End-Points Assessment Questionnaire (KEPAQ): the ABCDEF keratoconus classification"],"prefix":"10.1186","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4041-9370","authenticated-orcid":false,"given":"Kepa","family":"Balparda","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2785-1337","authenticated-orcid":false,"given":"Tatiana","family":"Herrera-Chalarca","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Melissa","family":"Cano-Bustamante","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2022,5,8]]},"reference":[{"key":"288_CR1","doi-asserted-by":"publisher","first-page":"1287","DOI":"10.2147\/OPTH.S254370","volume":"14","author":"K Balparda","year":"2020","unstructured":"Balparda K, Herrera-Chalarca T, Silva-Quintero LA, Torres-Soto SA, Vanegas-Ram\u00edrez CM. Development and validation of the \u201cKeratoconus End-Points Assessment Questionnaire\u201d (KEPAQ), a disease-specific instrument for evaluating subjective emotional distress and visual function through Rasch analysis. Clin Ophthalmol. 2020;14:1287\u201396.","journal-title":"Clin Ophthalmol"},{"issue":"3","key":"288_CR2","doi-asserted-by":"publisher","first-page":"395","DOI":"10.1097\/OPX.0000000000001035","volume":"94","author":"J Khadka","year":"2017","unstructured":"Khadka J, Schoneveld PG, Pesudovs K. Development of a keratoconus-specific questionnaire using Rasch analysis. Optom Vis Sci. 2017;94(3):395\u2013403.","journal-title":"Optom Vis Sci"},{"key":"288_CR3","doi-asserted-by":"publisher","first-page":"1839","DOI":"10.2147\/OPTH.S261785","volume":"14","author":"K Balparda","year":"2020","unstructured":"Balparda K, Herrera-Chalarca T, Silva-Quintero LA, Torres-Soto SA, Segura-Mu\u00f1oz L, Vanegas-Ramirez CM. 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