Outcomes of Augmented Relaxing Incisions for Postpenetrating Keratoplasty Astigmatism in Keratoconus

PURPOSE:To determine the outcomes of augmented relaxing incisions (relaxing incisions and counter-quadrant compression sutures) as graft refractive surgery (GRS) in keratoconic eyes. PATIENTS AND METHODS:This interventional case series included keratoconic eyes undergoing GRS for intolerable amounts of postpenetrating keratoplasty (PKP) astigmatism. Relaxing incisions were made in the graft-host interface down to Descemet membrane on both sides of the steepest meridian. Interrupted 10-0 nylon compression sutures were added in the opposite meridian to overcorrect astigmatism. Selective suture removal was initiated after 3-6 weeks to achieve tolerable amounts of astigmatism. Best-corrected visual acuity and refractive and keratometric astigmatisms were compared before and after the operation using simple subtraction and vector analysis methods. RESULTS:Overall, 77 eyes of 77 patients including 51 (66.2%) male and 26 (33.8%) female subjects with mean age of 30.0 ± 10.2 years at the time of PKP were studied. Average follow-up was 61.5 ± 33.5 months after PKP and 40.8 ± 29.3 months after GRS. Mean best-corrected visual acuity improved from 0.31 ± 0.26 logMAR (20/40) before GRS to 0.18 ± 0.12 logMAR (20/30) postoperatively (P < 0.001). Mean preoperative and postoperative values for refractive astigmatism, keratometric astigmatism, and spherical equivalent refractive error were 6.8 ± 1.4 and 3.9 ± 1.6 diopters (D) (P < 0.001), 7.9 ± 1.9 and 4.5 ± 2.2 D (P < 0.001), and −2.0 ± 2.9 and −3.24 ± 2.8 D (P < 0.001), respectively. Vector analysis demonstrated that refractive and keratometric astigmatisms were reduced by 4.8 and 5.9 D, respectively. CONCLUSIONS:GRS using augmented relaxing incisions reduces post-PKP astigmatism in keratoconic eyes; however, it causes a slight myopic shift.