Two-Stage LASIK With Relaxing Incisions Under the Corneal Flap Reduces High Astigmatism After Penetrating Keratoplasty

Abstract

Purpose:: To combine LASIK with relaxing incisions under the corneal flap in a two-stage sequence to test the reliability of reducing large amounts of astigmatism that commonly occur after penetrating keratoplasty.

Methods:: A prospective case series of penetrating keratoplasty patients was selected who had 5 diopters or more of stable topographic astigmatism following removal of all corneal transplant sutures. Stage 1 treatment: Following microkeratome formation and lifting of the LASIK flap, 450 micron deep intrastromal relaxing incisions were placed parallel to the transplant wound, centered on the steep meridian. Stage 2 treatment: When the topography was stable, the excimer laser was used to treat the full refractive error similar to standard LASIK enhancement.

Results:: Nineteen patients met the selection criteria. Topographically measured corneal transplant astigmatism before Stage 1 treatment averaged 9.13 ± 2.92 (SD) diopters (range=5.75-16.13). After topographic stabilization following the Stage 1 treatment of cutting the LASIK flap and placing corneal transplant relaxing incisions under the flap, the average topographic astigmatism was reduced by 45% to 4.98 ± 3.14 diopters (range=1.13-13.21, p<0.001). Three patients were satisfied with their optically corrected result following Stage 1 (best spectacle corrected visual acuity (BSCVA): 20/20, 20/25, and 20/50), and did not proceed to Stage 2 treatment with the excimer laser. The remaining sixteen patients completed Stage 2 treatment of their full refractive error with the excimer laser. Two patients each had 2 and 3 excimer laser treatments. Topographic corneal transplant astigmatism following Stage 2 averaged 2.37 ± 1.60 diopters (range=0.22-5.96, p (pre-Stage 1) <0.001, p (post-Stage 1) <0.001), for a total reduction of 74%. The final BSCVA of all patients completing the Stage 2 treatment ranged from 20/20 to 20/40.

Conclusions:: Combining LASIK with penetrating keratoplasty intrastromal relaxing incisions under the LASIK flap in a 2-stage process reliably reduced high topographic astigmatism by an average of 74% with all patients showing improvement.

Keywords: cornea: clinical science • refractive surgery: LASIK • astigmatism