Ten-year Follow-up of Excimer Laser Surface Ablation for Myopia in Thin Corneas
Accepted 11 December 2008. published online 25 February 2009.
Purpose
To evaluate the long-term outcomes of excimer laser surface ablation performed on thin corneas.
Design
Retrospective study.
Methods
We included in the study 75 eyes (49 patients) with a preoperative central corneal thickness (CCT) thinner than 500 μm that had undergone surface ablation to correct their myopia and that had at least 10 years of follow-up. We evaluated the stability of visual acuity (VA) and refraction, the predictability, corneal keratometry, safety, efficacy, and postoperative complications at the examinations 3 months and 1, 2, 5, and 10 years after surgery.
Results
Preoperative CCT was 481.54 ± 15.7 μm (range, 438 to 499 μm). Preoperative spherical equivalent was −6.12 ± 2.67 diopters (D) (range, −2 to −14 D). The best spectacle-corrected VA significantly improved (P < .01) during the follow-up. The uncorrected VA showed significant improvement in all visits when compared with the 3-month postoperative visit. Both the sphere and cylinder showed a slight but significant regression (P < .01) only in the comparison between 3 months and 10 years after the surgery. Ten years after the surgery, 30 eyes (40%) were within 0.50 D and 43 eyes (57.33%) were within 1.00 D of emmetropia. The safety index improved over the 10 year period and was always higher than 0.9. The efficacy index remained stable around 0.8. The topography did not show signs of corneal ectasia and the keratometry showed no increase in corneal power. Thirty eyes (40%) needed enhancement.
Conclusion
Surface ablation seems to be safe and effective to correct myopia in corneas thinner than 500 μm, with stable visual and refractive outcomes in a 10-year follow-up.
ABSTRACT