Purpose:
To determine effect of ablation decentration on postoperative high order aberrations after PRK operations.
Material and Method:
Medical records of 378 cases underwent refractive surgery with PRK were studied retrospectively. Postoperative ablation decentration was calculated with comparision of preoperative and postoperative corneal topography images. Total wavefront aberrations were measured preoperatively and postoperatively. Difference between preoperative and postoperative wavefront aberrations were compared. Correlation among magnitude of ablation decentration and high order aberrations were studied.
Results:
Mean high order RMS was 0.42±0.05 µ preoperatively and 0.33±0.02 µ postoperatively and mean postoperative high order RMS was significanly lower than postoperative RMS (p=0.001). Mean decentarion magnitude was 0.25±0.01mm. Mean postoperative values of high order aberrations was 0.150±0.03 µ for vertical coma, -0.090±0.03 µ for horizontal coma, 0.024±0.03 µ for negative trifoil, -0.068±0.03 µ for positive tirfoil, and -0.083±0.03 µ for spherical aberrations. Magnitude of decentration did not correlated significantly with postoperative high order aberrations except spherical aberration. (r=0.20 and p=0.001)
Conclusion:
There was only a significant correlation between magnitude of postoperative decentration and postoperative spherical aberration. It seems that decentration does not have a significant effect on other types of postoperative high order aberrations.
Keywords: PRK, decentration, high order aberrations