AIM: To assess the outcome of intrastromal corneal ring segments (Kera ring) for keratoconus.
Study design: Retrospective noncomparative interventional case series.
Patients and Methods: Sixty keratoconus eyes of 48 patients that had intrastromal corneal ring segments (Kera ring) implantation mechanically were reviewed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), central corneal curvature, corneal astigmatism, and complications were analyzed.
Results: At a mean follow-up period of 6 months, the UCVA improved in 90% of eyes, was unchanged in 10%, and none worsened. The BSCVA improved in 94% of eyes, was unchanged in 6%, and none worsened. The mean spherical equivalent (SE) was reduced from 7.42 ± 2.5 diopters (D) to 3.06 ± 2.33 D. and the mean refractive astigmatism, from 4.52 ± 1.61 D to 2.61 ± 1.69 D. The mean central corneal curvature was reduced from 51.45 ± 3.04 D to 47.37 ± 2.58 D. Intracorneal ring segment decentration occurred in 2 eyes (3.3%), segment extrusion in 10 eyes (16.7%), bacterial keratitis in 1 eye (1.7%) with segment extrusion, and a disciform keratitis in 1 eye (1.7%).
Conclusion: Implantation of Kera ring segments in patients with keratoconus was a safe, effective and reversible procedure that led to stable results, on the short term of six months. Further clinical and experimental studies with more patients and longer follow-up are needed.