Comparison of 2 types of intrastromal corneal ring segments for keratoconus.

Purpose: To assess the effectiveness and safety of 2 types of 6.0 mm intrastromal corneal ring segments (ICRS) in patients with mild to severe keratoconus.
Setting: Lebanese American University, Beirut, Lebanon.
Design: Retrospective comparative case series.
Methods: Eyes had implantation of Intacs SK ICRS (Group 1) or Keraring SI6 ICRS (Group 2). Visual acuity (logMAR), refraction, keratometry, and higher-order aberrations were compared 6 months and 1 year postoperatively.
Results: Group 1 comprised 66 eyes and Group 2, 107 eyes. The groups were comparable preoperatively. One-year postoperatively, the mean uncorrected distance visual acuity improved by 0.62 logMAR ± 0.19 (SD) in Group 1 and by 0.67 ± 0.17 logMAR in Group 2 (P=.211). The mean corrected distance visual acuity improved by 0.12 ± 0.11 logMAR and by 0.08 ± 0.13, respectively (P=.301). The spherical equivalent decreased by a mean of 2.80 ± 2.87 D and 2.65 ± 3.00 D, respectively (P=.572). Keratometry (K) flat and K steep decreased by a mean of 1.51 ± 1.57 D and 2.24 ± 1.61 D, respectively, in Group 1 and by 1.10 ± 2.00 D and 1.44 ± 1.64 D, respectively, in Group 2 (P=.667 and P=.184, respectively). Primary coma root mean square decreased by a mean of 1.09 ± 0.66 μm in Group 1 and 0.99 ± 0.72 μm in Group 2 (P=.716).
Conclusion: Both ICRS models significantly improved visual function in patients with keratoconus, with comparable postoperative profiles and no major complications.
Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
(Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)