Comparison of Anterior Corneal Optical Aberration Induced by CK and Hyperopic LASIK

To investigate anterior corneal optical higher order aberration (HOA) induced by conductive keratoplasty (CK) and laser in situ keratomileusis (LASIK). 69 eyes with hyperopia or presbyopia were enrolled. 47 eyes of 47 patients underwent CK procedure, 22 eyes underwent LASIK. Data were acquired preoperatively, and at 3 and 6 months postoperatively. The total Root Mean Square (RMS) of the HOA as well as the individual Zernike polynomials of coma, trefoil, and spherical aberration were analyzed. In CK group, the high order RMS showed significant elevation at 3 months, but it returned to near preoperative levels at 6 months postoperatively. Trefoil (Z33) is the exclusive Zenike pattern to increase significantly following CK, peaking at 3 months and then decreasing back to near preoperative level at 6 months after CK. In the hyperopic LASIK group, coma increased to a peak at 3 month postoperatively, and persisted at sixth month after LASIK. Spherical aberration decreased significantly at 3 months and persisted till the sixth postoperative month. There was significant correlation between ΔSE and Δspherical aberration showed in both groups. The HOA and main Zernike polynomials pattern and their natural changes induced by CK is significantly different from that induced by LASIK in the hyperopic corrected treatment. The amount of achieved hyperopic corrections induced by CK or LASIK is not correlated to the change of HOA patterns such as coma and trefoil, but it is correlated to the change of spherical aberration.