Intrastromal corneal ring segments (ICRSs) are small arc-like implants that are being used increasingly as a minimally invasive treatment for patients with keratoconus. This study assessed the effectiveness of KeraRing implants, a type of ICRS, to treat keratoconus.
Retrospective case series descriptive study of 43 patients (55 eyes) with keratoconus who underwent KeraRing implantation from February 2008 to June 2009. Patients who had intraoperative or postoperative complications and/or did not complete at least 6 months of follow-up were excluded. All patients underwent complete ophthalmologic examinations that included measurement of the uncorrected visual acuity (UCVA), best spectacle–corrected visual acuity (BSCVA), manifest refraction, and keratometry before and 2 days, 2 weeks, 1 month, and 3 and 6 months after surgery. The ring segments were chosen based on a nomogram from the manufacturer.
Six months postoperatively, the mean UCVA increased significantly (P < 0.05) from 0.10 ± 0.11 to 0.32 ± 0.25 and the mean BSCVA increased from 0.36 ± 0.23 to 0.57 ± 0.24 (P < 0.05). The mean spherical refractive error significantly (P < 0.05) improved from −4.85 ± 2.90 diopters (D) to −1.89 ± 2.68 D, and the mean cylindrical refractive error significantly (P < 0.05) improved from −3.65 ± 1.70 D to −2.60 ± 1.62 D. The mean spherical equivalent significantly (P < 0.05) decreased from −6.68 ± 2.93 D to −3.19 ± 2.75 D, and the mean keratometry value decreased from 51.83 ± 4.14 D to 47.27 ± 3.68 D. The improvement in the UCVA and BSCVA continued over the 6-month postoperative period, but significant changes occurred only during the first 3 months. These changes occurred in patients with all grades of keratoconus.
KeraRing implantation provided significant improvement in visual acuity, spherical equivalent, and keratometry results. This ICRS is an effective treatment for managing keratoconus and might delay or even avoid the need for penetrating keratoplasty.
From the *Department of Ophthalmology, The University of Jordan and Jordan University Hospital, Amman, Jordan; and †Department of Nursing, Jordan University Hospital, Amman, Jordan.
Received for publication November 28, 2010; revision received April 20, 2011; accepted April 24, 2011.
The authors state that they have no proprietary interest in the products named in this article.
Reprints: Almutez M. Gharaibeh, Department of Ophthalmology, Faculty of Medicine, The University of Jordan and Jordan University Hospital, PO Box 13046, Amman 11942, Jordan (e-mail: firstname.lastname@example.org).