Accelerated Corneal Collagen Cross-Linking in Thin Keratoconic Corneas

Abstract

Original Article Engin Bilge Ozgurhan, MD; Betul Ilkay Sezgin Akcay, MD; Tugba Kurt, MD; Yusuf Yildirim, MD; Ahmet Demirok, MD To report the outcomes of accelerated corneal collagen cross-linking in patients with thin corneas (minimum corneal thickness < 400 µm). Thirty-four eyes of 34 patients with a minimum corneal thickness less than 400 µm were included. All patients underwent accelerated corneal collagen cross-linking (irradiance power of 30 mW/cm² at 3 minutes with a total surface dose of 5.4 J/cm²). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest refraction (diopters [D]), and topography were evaluated at baseline and at the 1-, 6-, and 12-month follow-up visit. Endothelial cell density (cells/mm²) was calculated preoperatively and postoperatively at 12 months. The corneal stromal demarcation line was measured using anterior segment optical coherence tomography at 1 month postoperatively. The mean age of all patients (14 women and 20 men) was 23.08 ± 3.90 years (range: 16 to 29 years). UDVA and CDVA increased but not significantly. UDVA improved from 0.67 ± 0.32 (20/93 ± 20/41 Snellen) to 0.56 ± 0.28 logMAR (20/72 ± 20/38 Snellen) (P = .033) and CDVA improved from 0.49 ± 0.19 (20/61 ± 20/30 Snellen) to 0.42 ± 0.19 logMAR (20/52 ± 20/30 Snellen) (P = .009) at the last follow-up visit. The mean spherical and cylindrical refractions did not significantly change (P = .100 and 0.139, respectively). At the last follow-up visit, the flat keratometry decreased from 47.40 ± 2.52 to 46.95 ± 2.48 D, steep keratometry decreased from 51.04 ± 3.71 to 50.62 ± 3.57 D, and apex keratometry decreased from 57.58 ± 4.49 to 56.26 ± 4.47 D (P = .001, = .0019, = .001, respectively) from baseline. The mean endothelial cell density changed from 2,726.02 ± 230.21 to 2,714.58 ± 218.26 cells/mm² at 12 months postoperatively (P =.086). The results of this study revealed that accelerated corneal collagen cross-linking stabilized the progression of keratoconus without a significant endothelial cell density loss during the 12 months of follow-up. [J Refract Surg. 2015;31(6):386–390.] From the Department of Ophthalmology, Beyoglu Eye Training and Research Hospital, Istanbul, Turkey (EBO, TK, YY); the Department of Ophthalmology, Umraniye Training and Research Hospital, Istanbul, Turkey (BISA); and the Department of Ophthalmology, Istanbul Medeniyet University Medical School, Istanbul, Turkey (AD). The authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONS Study concept and design (EBO); data collection (EBO, TK); analysis and interpretation of data (EBO, BISA, TK, YY, AD); writing the manuscript (EBO, BISA); critical revision of the manuscript (EBO, BISA, TK, YY, AD) Correspondence: Engin Bilge Ozgurhan, MD, Beyoglu Eye Training and Research Hospital, Bereketzade Camii Sok, 34421, Kuledibi, Beyoglu, Istanbul, Turkey. E-mail: enginbilge@gmail.com To report the outcomes of accelerated corneal collagen cross-linking in patients with thin corneas (minimum corneal thickness < 400 µm). Thirty-four eyes of 34 patients with a minimum corneal thickness less than 400 µm were included. All patients underwent accelerated corneal collagen cross-linking (irradiance power of 30 mW/cm² at 3 minutes with a total surface dose of 5.4 J/cm²). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest refraction (diopters [D]), and topography were evaluated at baseline and at the 1-, 6-, and 12-month follow-up visit. Endothelial cell density (cells/mm²) was calculated preoperatively and postoperatively at 12 months. The corneal stromal demarcation line was measured using anterior segment optical coherence tomography at 1 month postoperatively. The mean age of all patients (14 women and 20 men) was 23.08 ± 3.90 years (range: 16 to 29 years). UDVA and CDVA increased but not significantly. UDVA improved from 0.67 ± 0.32 (20/93 ± 20/41 Snellen) to 0.56 ± 0.28 logMAR (20/72 ± 20/38 Snellen) (P = .033) and CDVA improved from 0.49 ± 0.19 (20/61 ± 20/30 Snellen) to 0.42 ± 0.19 logMAR (20/52 ± 20/30 Snellen) (P = .009) at the last follow-up visit. The mean spherical and cylindrical refractions did not significantly change (P = .100 and 0.139, respectively). At the last follow-up visit, the flat keratometry decreased from 47.40 ± 2.52 to 46.95 ± 2.48 D, steep keratometry decreased from 51.04 ± 3.71 to 50.62 ± 3.57 D, and apex keratometry decreased from 57.58 ± 4.49 to 56.26 ± 4.47 D (P = .001, = .0019, = .001, respectively) from baseline. The mean endothelial cell density changed from 2,726.02 ± 230.21 to 2,714.58 ± 218.26 cells/mm² at 12 months postoperatively (P =.086). The results of this study revealed that accelerated corneal collagen cross-linking stabilized the progression of keratoconus without a significant endothelial cell density loss during the 12 months of follow-up. [J Refract Surg. 2015;31(6):386–390.] From the Department of Ophthalmology, Beyoglu Eye Training and Research Hospital, Istanbul, Turkey (EBO, TK, YY); the Department of Ophthalmology, Umraniye Training and Research Hospital, Istanbul, Turkey (BISA); and the Department of Ophthalmology, Istanbul Medeniyet University Medical School, Istanbul, Turkey (AD). The authors have no financial or proprietary interest in the materials presented herein. AUTHOR CONTRIBUTIONS Study concept and design (EBO); data collection (EBO, TK); analysis and interpretation of data (EBO, BISA, TK, YY, AD); writing the manuscript (EBO, BISA); critical revision of the manuscript (EBO, BISA, TK, YY, AD) Correspondence: Engin Bilge Ozgurhan, MD, Beyoglu Eye Training and Research Hospital, Bereketzade Camii Sok, 34421, Kuledibi, Beyoglu, Istanbul, Turkey. E-mail: enginbilge@gmail.com 10.3928/1081597X-20150521-11