Aberrometric Outcomes of Intrastromal Corneal Ring Segment (KeraRing 355) Implantation Using PocketMaker Microkeratome in Patients with Keratoconus

Abstract

Objective: To evaluate aberrometric changes in corneas with keratoconus implanted with intrastromal corneal ring segment (Keraring 355) during a 3-months follow-up. Design: Prospective, consecutive case series Methods: In this interventional study, 22 eyes of 21 keratoconic patients with mean age of 29 ± 6 years who underwent KeraRing 355 intrastromal corneal ring insertion using a Pocket Maker Microkeratome for channel creation and completed at least three months of follow-up were included. Uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), refractive outcome, Orbscan finding and corneal aberrations were assessed. Results: Three months postoperately, Low order aberration (defocus and astigmatism) decreased significantly (P<0.001). No statistically significant changes were detected in total RMS, trefoil, secondary trefoil and coma. Moreover, a statistically significant increase in quatrefoil, secondary coma, spherical aberration and secondary spherical was found. In term of visual outcomes, the mean UCVA (in LogMAR value) improved significantly from 0.75 ± 0.33 to 0.31 ± 0.23 and the mean BSCVA improved (from 0.31 ± 0.16 to 0.19 ± 0.15) (P<0.05). The mean spherical refractive error improved (from -1.37 ± 1.36 to 0.01 ± 2.47) and the mean cylindrical refractive error decreased significantly (from -3.8 ± 1.03 to -2.1 ± 1.27 (P<0.001)). Also, the mean keratometry value decreased from 47.61 ± 2.03 to 42.50 ± 2.76. Conclusion: KeraRing 355 implantation provided significant improvement in low order aberrations but was not effective in high order aberrations (HOA) in low/moderate keratoconus patients. However, UCVA, BCVA, spherical and cylindrical refractive error and keratometry results improved significantly.