Laser in-situ keratomileusis after penetrating keratoplasty.

Laser in situ keratomileusis (LASIK) after penetrating keratoplasty has been used more commonly for the correction of myopia or myopic astigmatism and less so for hypermetropia or hyperopic astigmatism. The primary goal after LASIK in such cases is resolution of sufficient myopia and astigmatism to allow spectacle correction of the residual refractive error and decrease anisometropia. All sutures should be removed prior to LASIK and the interval between penetrating keratoplasty and LASIK should be a minimum of 1 year. Preoperative evaluation includes refraction, slit-lamp biomicroscopy, corneal topography, and specular microscopy. The technique of LASIK surgery after penetrating keratoplasty is similar to the standard procedure. However, many variations have been described. These include maneuvers during surgery such as augmentation with arcuate cuts on the stromal bed and topographically guided LASIK. Other variations are relaxing incisions followed by LASIK surgery and sequential treatment by LASIK, that is, raising of the flap as a first stage procedure followed by ablation if required, 4 to 6 weeks later after relifting the flap in the second stage. Improvement in both uncorrected visual acuity and spectacle-corrected visual acuity, as well as a decrease in spherical equivalent, cylinder, and anisometropia, has been reported in various studies. All grafts were clear and no occurrence of wound dehiscence has been reported. Intraoperative complications include hemorrhage, microkeratome failure, flap buttonhole, dislocation, and perforation. Postoperative complications include undercorrection, decentered ablation, and regression. Re-enhancements after LASIK following keratoplasty are possible with acceptable visual outcome.