Abstract
Purpose: :
To determine the incidence of corneal ectasia, suspicious cases and the risk factors related with, in patients were refractive surgery was performed.
Methods: :
A retrospective, longitudinal and observational study. Patient's records who underwent refractive surgery with any kind of the known techniques (LASEK, PRK or LASIK) in the period between May 1 2005 to May 31, 2007 in the Cornea department of our institution were reviewed. Ectasia post surgery was defined as: BCVA 20/30 or worst, central pachometry ≤ 400 µm, ablation depth > 76 µm, icreasing of astigmatism > 1.25 D., residual myopia > 2.0 D., topographic findings of asymmetric corneal toricity > 1.40 D.Suspicious case post surgery was defined as: < 400 µm, BCVA 20/25 or better. Ablation depth > 76 µm and < 100 µm, and without the other criteria for ectasia.
Results: :
1170 eyes out of f 604 patients were operated on. 9 cases were included in the suspicious group. The spherical equivalent was -5.47 D, the average ablation diameter zone was 5.5 mm, the average of ablation deepness was 95.2 µm, The preoperative central pachometry was 557.9 µm, and the postoperative was 378.1 µm. 2 eyes were diagnosed with ectasia (0.17%). The spherical equivalent was -6.50 D, the average ablation diameter zone was 5.25 mm, the average of ablation deepness was 105 µm, The preoperative central pachometry was 539.5 µm, and the postoperative was 389 µm.
Conclusions: :
The incidence of ectasia was 0.17% . The most important risk factor found in this study was ablation > 100 microns.Keywords: corneal ectasia, refractive surgery, incidence, risk factors.
Keywords: refractive surgery: complications • clinical (human) or epidemiologic studies: risk factor assessment • refractive surgery