Adjustment of Intrastromal Corneal Ring Segments After Unsuccessful Implantation in Keratoconic Eyes

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To evaluate visual, refractive, and corneal topography outcomes in eyes with keratoconus that have undergone exchange/adjustment surgery with a new intrastromal corneal ring segment (ICRS) combination after unsuccessful visual and/or refractive outcomes after primary ICRS surgery.


A retrospective nonrandomized case series was conducted including consecutive eyes of patients with keratoconus that underwent ICRS adjustment after an unsuccessful visual outcome. Patients were divided into 2 groups: group 1 was made up of patients with Intacs ICRSs that were exchanged for the Ferrara ICRS type, and group 2 consisted of patients who maintained the same ICRS type after undergoing ICRS adjustment surgery (change of the arc length or thickness). Uncorrected distance visual acuity, best-corrected distance visual acuity (CDVA), keratometry, asphericity, higher-order aberrations, and corneal regularity indexes (ISV and IHD) (Pentacam HR; OCULUS) were assessed preoperatively and 12 months after each procedure.


Twenty-six eyes from 26 patients were included, 8 eyes in group 1 and 18 eyes in group 2. The eyes in both groups improved their CDVA values after ICRS exchange, in group 1 from 0.27 ± 0.11 preoperatively to 0.54 ± 0.17 postoperatively (P = 0.001), and in group 2 from 0.34 ± 0.22 to 0.61 ± 0.15 (P < 0.0001). In both groups, there was also a significant improvement in the refractive cylinder, topographic cylinder, and coma after ICRS adjustment (P < 0.05).


ICRS implantation has been shown to be a reversible and adjustable surgical procedure for keratoconus treatment. Good outcomes can be obtained after ICRSs are exchanged.

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