Treatment of postoperative keratoplasty astigmatism using femtosecond laser-assisted intrastromal relaxing incisions.

Purpose: To investigate the effectiveness of femtosecond laser-assisted intrastromal relaxing incisions for astigmatism management and establish laser treatment parameters.
Methods: Sixteen eyes of 16 patients had regular astigmatism after penetrating keratoplasty. All sutures had been removed and the refraction was stabilized. Paired arcuate intrastromal incisions were made 180° apart within the graft stroma with a femtosecond laser preserving the epithelium. Follow-up examinations were performed at 1 week, 2 weeks, 1 month, and 3 months.
Results: The logMAR corrected distance visual acuity (CDVA) improved from 0.50 ± 0.29 to 0.32 ± 0.23 (Snellen 20/63 to 20/40). Refractive and topographic anterior cylinders decreased from 6.8 ± 2.2 diopters (D) to 3.7 ± 1.7 D and from 9.5 ± 4.8 D to 4.4 ± 2.1 D, respectively. Stabilization of topographic cylinder was observed 1 month postoperatively. The worse the preoperative CDVA was and the higher the preoperative values for the refractive and topographic cylinders were, the higher the surgically induced changes were. Anterior side cut angles at 90° and 120° produced similar results. A bulge of incision occurred in one eye requiring compression sutures.
Conclusions: Significant improvement in CDVA and refractive and topographic cylinders indicated a good effect of femtosecond laser-assisted intrastromal relaxing incisions in reducing astigmatism. No advantage between 90° and 120° anterior side cut angles was found. No infections were recorded and no patient expressed discomfort.
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