Purpose:
To evaluate the efficacy of intra-corneal ring segments in the treatment of post-keratoplasty astigmatism.
Methods:
A retrospective comparative series of cases study that included 23 eyes from 22 patients with astigmatism post-keratoplasty higher than 3.5 diopters and contact lens intolerance was made. Intra-corneal ring segments (Ferrara - Mediphacos and Keraring - Mediphacos) were implanted in a tunnel performed by the FS60 IntraLase Femtosecond laser (AMO, Inc. Santa Ana, California, USA). Patients were divided in three groups according to the arch and thickness of the segments that were used. Group 1: equal segments of 120º and 300 µ; Group 2: equal segments of 90º and 300 µ; Group 3: two segments of different arch and/or thickness. UCVA, BCVA, sphere, refractive, keratometric, and topographic astigmatism and comatic aberrations were studied. Pre and postoperative data were compared using statistical non-parametric test.
Results:
In all the cases, refractive astigmatism showed a statistical significant reduction (p=0.005, p=0,017 and p=0,027). The rest of the parameters also were reduced but the variation was not significant in all the groups. No surgical or postoperative complications were observed.
Conclusions:
Intra-corneal ring segments implantation can be an effective treatment for high astigmatism post-keratoplasty. Further studies are necessary to corroborate these results and to establish what size of segments to use in each case.
Keywords: refractive surgery: corneal topography • transplantation • cornea: clinical science