{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T20:31:02Z","timestamp":1777581062166,"version":"3.51.4"},"reference-count":25,"publisher":"SAGE Publications","issue":"5","license":[{"start":{"date-parts":[[2021,3,16]],"date-time":"2021-03-16T00:00:00Z","timestamp":1615852800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["European Journal of Ophthalmology"],"published-print":{"date-parts":[[2021,9]]},"abstract":"<jats:sec>\n                    <jats:title>Purpose:<\/jats:title>\n                    <jats:p>To evaluate clinical outcomes in patients with asymmetric duck phenotype keratoconus implanted with asymmetric progressive thickness intrastromal corneal ring segments (PT-ICRS, Keraring AS, Mediphacos, Belo Horizonte, Brazil), and to demonstrate improved visual acuity and symmetry in corneal flattening.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>This single-center, retrospective, observational study evaluated the clinical outcomes at 1, 3, and 6\u2009months after implantation of PT-ICRS in patients with duck phenotype keratoconus. After creating the intrastromal tunnel with a femtosecond laser, one 160-degree arc length PT-ICRS, either 150\/250\u2009\u00b5m or 200\/300\u2009\u00b5m, was implanted. Changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction (MR), manifest refraction spherical equivalent (MRSE), mean keratometry (Kmean), maximum keratometry (Kmax), Coma@5mm, and manifest and topographical astigmatism were documented.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>The study cohort included 23 eyes of 17 patients with a mean age of 24.6\u2009years. From baseline to 6\u2009months following implantation, mean UDVA improved from 0.70 logarithm of the minimum angle of resolution (logMAR) (20\/100 Snellen) to 0.22 logMAR (20\/33 Snellen), CDVA improved from 0.33 logMAR (20\/42 Snellen) to 0.14 logMAR (20\/27 Snellen), the mean sphere and MRSE decreased from \u22121.05\u2009diopters (D) and \u22122.70\u2009D to \u22120.25\u2009D and \u22120.80\u2009D, respectively, and the Kmean and Kmax improved from 46.5\u2009D and 53.7\u2009D to 44.6\u2009D and 48.7\u2009D, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions:<\/jats:title>\n                    <jats:p>The Keraring AS ICRS offers a safe, effective means of improving visual acuity while reducing refractive error, mean and max keratometry, and aberrations in patients with duck phenotype keratoconus.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1177\/11206721211001722","type":"journal-article","created":{"date-parts":[[2021,3,17]],"date-time":"2021-03-17T01:49:43Z","timestamp":1615945783000},"page":"2191-2199","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":15,"title":["Efficacy of progressive thickness intrastromal corneal ring segments in the treatment of duck phenotype keratoconus"],"prefix":"10.1177","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5054-6077","authenticated-orcid":false,"given":"Juan G","family":"Arbelaez","sequence":"first","affiliation":[{"name":"Muscat Eye Laser Center, Muscat, Shatti Al Qurum, Sultanate of Oman"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maria C","family":"Arbelaez","sequence":"additional","affiliation":[{"name":"Muscat Eye Laser Center, Muscat, Shatti Al Qurum, Sultanate of Oman"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2021,3,16]]},"reference":[{"key":"bibr1-11206721211001722","volume-title":"Cornea - surgery of the cornea and conjunctiva","volume":"2","author":"Krachmer JH","year":"2010","edition":"3"},{"key":"bibr2-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/0039-6257(84)90094-8"},{"key":"bibr3-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/01.ico.0000164831.87593.08"},{"key":"bibr4-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/j.ophtha.2006.11.033"},{"key":"bibr5-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/ICO.0000000000000978"},{"key":"bibr6-11206721211001722","doi-asserted-by":"publisher","DOI":"10.2147\/OPTH.S120267"},{"key":"bibr7-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/ICO.0b013e3182215a15"},{"key":"bibr8-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1167\/iovs.09-5017"},{"key":"bibr9-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/00004397-196606010-00004"},{"key":"bibr10-11206721211001722","doi-asserted-by":"publisher","DOI":"10.3928\/1081-597X-19950701-08"},{"key":"bibr11-11206721211001722","doi-asserted-by":"publisher","DOI":"10.3928\/1081-597X-19910101-14"},{"key":"bibr12-11206721211001722","doi-asserted-by":"crossref","first-page":"15","DOI":"10.4103\/0974-9233.61212","volume":"17","author":"Espandar L","year":"2010","journal-title":"Middle East Afr J Ophthalmol"},{"key":"bibr13-11206721211001722","first-page":"115","volume-title":"Atlas of anterior segment Oct","volume":"2","author":"Arbelaez JG.","year":"2019"},{"key":"bibr14-11206721211001722","first-page":"165","volume-title":"Biomec\u00e1nica y Arquitectura Corneal","author":"Alfonso JF","year":"2014"},{"key":"bibr15-11206721211001722","unstructured":"Gordillo CH, Grandin JC, Lotfi AC. Asymmetrical base intracorneal ring segment can be used for keratoconus treatment. Healio website, https:\/\/www.healio.com\/ophthalmology\/cornea-external-disease\/news\/print\/ocular-surgery-news\/{55000807-f6e0-44fa-bd81-54421ddf7e26}\/ (2019, accessed 9 January 2020)."},{"key":"bibr16-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/ICO.0000000000002160"},{"key":"bibr17-11206721211001722","doi-asserted-by":"crossref","first-page":"4058026","DOI":"10.1155\/2017\/7589816","volume":"2017","author":"Fern\u00e1ndez-Vega Cueto L","year":"2017","journal-title":"J Ophthalmol"},{"key":"bibr18-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/j.joco.2016.03.001"},{"key":"bibr19-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/j.ophtha.2007.01.008"},{"key":"bibr20-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/j.jcrs.2012.05.031"},{"key":"bibr21-11206721211001722","doi-asserted-by":"publisher","DOI":"10.3928\/1081597X-20130318-06"},{"key":"bibr22-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1177\/1120672120952346."},{"key":"bibr23-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1016\/j.ajo.2007.12.022"},{"key":"bibr24-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1007\/s10792-020-01467-5"},{"key":"bibr25-11206721211001722","doi-asserted-by":"publisher","DOI":"10.1097\/ICO.0000000000002062"}],"container-title":["European Journal of Ophthalmology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/11206721211001722","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/full-xml\/10.1177\/11206721211001722","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/11206721211001722","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T19:44:08Z","timestamp":1777405448000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/11206721211001722"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,3,16]]},"references-count":25,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2021,9]]}},"alternative-id":["10.1177\/11206721211001722"],"URL":"https:\/\/doi.org\/10.1177\/11206721211001722","relation":{},"ISSN":["1120-6721","1724-6016"],"issn-type":[{"value":"1120-6721","type":"print"},{"value":"1724-6016","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,3,16]]}}}