Can opposite clear corneal incisions have a role with post-laser in situ keratomileusis astigmatism?

ABSTRACT

To evaluate the astigmatic correcting effect of paired opposite clear corneal incisions [OCCIs] on the steep axis in patients with residual astigmatism after laser in situ keratomileusis [LASIK] Thirty-one eyes of 24 patients with a mean age of 28.4 years +/- 2.46 [range, 19-36 years] were recruited for the study. Inclusion criteria included residual astigmatism of=1.5 diopter [D] after LASIK with inadequate residual stromal bed thickness that precluded ablation. The cohort was divided into two groups; group I [with astigmatism ranging from-1.5 D to-2.5 D] and group II [with astigmatism>-2.5 D]. The steep axis was marked prior to surgery. Paired three-step self-sealing opposite clear corneal incisions were performed 1-mm anterior to the limbus on the steep axis with 3.2-mm keratome for group I and 4.1 mm for group II. Patients were examined 1 day, 1 week, 1 month, 3 months and 6 months, postoperatively. Visual acuity, refraction, keratometry, and corneal topography were evaluated preoperatively and postoperatively. Analysis of the difference between groups was performed with the Student t-test. P<0.05 was considered statistically significant. The mean uncorrected visual acuity [UCVA] improved from 0.35 +/- 0.13 [range, 0.1-0.6] to 0.78 +/- 0.19 [range, 0.5-1] in group I and from 0.26 +/- 0.19 [range, 0.1-0.5] to 0.7 +/- 0.18 [range, 0.4-1] in group II. The increase in UCVA was statistically significant in both groups [P=0.001, both cases]. The mean preoperative and postoperative keratometric astigmatism in group I was 2.0 +/- 0.48 D [range, 1.5-2.5 D] and 0.8 +/- 0.37 D [range, 0.1-1.4 D], respectively. The decrease in keratometric astigmatism was highly statistically significant in group II [P=0.001.]. Mean surgically induced astigmatic reduction by vector analysis was 1.47 +/- 0.85 D and 2.21 +/- 0.97 D in groups I and II respectively. There were no incision-related complications. Conclusions: Paired OCCIs were predictable and effective in correcting post-LASIK astigmatism and required no extra surgical skill or expensive instruments. OCCIs are especially useful in eyes with insufficient corneal thickness for LASIK retreatment