{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T15:31:12Z","timestamp":1787758272134,"version":"build-2784847793"},"reference-count":25,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"8","content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2022,8]]},"abstract":"<jats:sec>\n                    <jats:title>Purpose:<\/jats:title>\n                    <jats:p>To evaluate the visual, refractive, tomographic, and topometric outcomes of progressive thickness intracorneal ring segment (PT-ICRS) implantation in duck-type keratoconus.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods:<\/jats:title>\n                    <jats:p>This retrospective study included eyes with oval (duck-type) keratoconus treated with PT-ICRS implantation. After the femtosecond laser tunnel creation, one PT-ICRS (Keraring AS 5 with 160\u00b0 arc length) was implanted along the ectatic, inferior half of the cornea. Data of uncorrected and corrected distance visual acuity (UDVA and CDVA), refraction, asphericity (Q value), and keratometry (K) were compared pre- and postoperatively. Additionally, changes in the topometric indices of corneal irregularity were also evaluated after PT-ICRS implantation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>\n                      Thirty-one eyes of 30 patients were included in the study with a mean follow-up time of 9.06 months (ranging between 6 and 18 months). UDVA improved from 0.85 \u00b1 0.36 to 0.27 \u00b1 0.14 logMAR (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001), and CDVA improved from 0.37 \u00b1 0.22 to 0.13 \u00b1 0.11 logMAR (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001). The mean spherical error decreased from \u22123.66 \u00b1 2.60 to \u22121.60 \u00b1 1.42 D (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001), and the mean cylindrical error decreased from \u22124.91 \u00b1 2.65 to \u2212 1.41 \u00b1 1.31 D (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001). All topographic parameters measured from the anterior cornea demonstrated statistically significant improvements after PT-ICRS implantation (\n                      <jats:italic toggle=\"yes\">P<\/jats:italic>\n                      = 0.001). K mean, K maximum, corneal astigmatism, and Q value showed a significant decrease. Besides the index of height asymmetry, all topometric indices were significantly reduced after PT-ICRS implantation. There were no loss of lines and no complications.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>PT-ICRS implantation in duck-type keratoconus is an effective and safe treatment. This intervention improves the visual acuity, refractive error, topographical, and topometric parameters significantly by decreasing both eccentricity and steepness of the cone.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/ijo.ijo_2770_21","type":"journal-article","created":{"date-parts":[[2022,8,4]],"date-time":"2022-08-04T11:45:11Z","timestamp":1659613511000},"page":"2939-2945","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":10,"title":["Clinical, tomographic, and topometric outcomes of progressive thickness intracorneal ring segment implantations in duck-type keratoconus"],"prefix":"10.4103","volume":"70","author":[{"given":"Efekan","family":"Coskunseven","sequence":"first","affiliation":[{"name":"Department of Refractive Surgery, Dunyagoz Etiler Hospital, Istanbul, Turkey"},{"name":"Faculty of Health Sciences, Istanbul Rumeli University, Istanbul, Turkey"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Belma","family":"Kayhan","sequence":"additional","affiliation":[{"name":"Department of Refractive Surgery, Dunyagoz Etiler Hospital, Istanbul, Turkey"},{"name":"Department of Ophthalmology, Sultan II. 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