Correction of High Astigmatism Post DALK With Femtosecond Laser–Assisted ICRS Implantation
Purpose
To evaluate the efficacy of femtosecond-assisted Keraring intrastromal ring segment (ICR) implantation in reducing high astigmatism in patients who have previously undergone deep anterior lamellar keratoplasty (DALK).
Methods
This retrospective, observational study included patients who had previously undergone DALK and after 1 year of the surgery presented with high residual astigmatism. Patients were implanted with Keraring ICRs (Mediphacos Ltda) using a femtosecond laser (IntraLase). Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), corneal keratometry (Orbscan Corneal Topographer, Bausch & Lomb) and corneal thickness (Visante) was measured preoperatively and at 1, 3, 6, and 12 months postoperatively.
Results
Twenty eyes of 19 patients (aged 42.75 ± 15.49 years) were analyzed. The mean time between corneal graft and ICRs surgery was 34 months. Mean UCVA (logMAR) changed from 1.15 ± 0.47 preoperatively to 0.19 ±0.14 postoperatively (p<0.001), and BCVA from 0.35 ± 0.19to1.2 ± 2.64 (p<.0001). Kmax decreased from 51.14 D preoperatively to 49.30 D (p<.0003) postoperatively, while Kmin changed from 43.07 D to 44.67 D. Mean cylinder decreased from -7.10 (range -3.50 to -10) to -4.2 (range -1 to -7). Mean pachymetry was 581±51.6 (SD) preoperatively vs 592±45 (SD) postoperatively.
Conclusion
Femtosecond-assisted Keraring implantation is a promising option for the management of high astigmatism in patients who have previously undergone DALK. In this study, Keraring implantation reduced topographic and refractive astigmatism, thus also improving visual acuity.