Outcomes of Augmented Relaxing Incisions for Postpenetrating Keratoplasty Astigmatism in Keratoconus

Abstract

To determine the outcomes of augmented relaxing incisions (relaxing incisions and counter-quadrant compression sutures) as graft refractive surgery (GRS) in keratoconic eyes. 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. 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. GRS using augmented relaxing incisions reduces post-PKP astigmatism in keratoconic eyes; however, it causes a slight myopic shift.