Clinical results of topography-guided laser-assisted in situ keratomileusis using the anterior corneal astigmatism axis and manifest refractive astigmatism axis

Purpose To evaluate the clinical results of primary topography-guided femtosecond laser-assisted in situ keratomileusis (TG-FS-LASIK) using the Pentacam-measured anterior corneal astigmatism axis (ACA) or manifest refractive astigmatism axis (MRA). Methods In this prospective cohort study, all eyes were treated with primary TG-FS-LASIK using the manifest cylinder. Thirty-two right eyes were treated using ACA with axis disparity > 5 degrees in the experimental group, and 32 right eyes were treated using MRA with axis disparity <= 5 degrees in the control group. Visual, refractive outcomes, and corneal higher-order aberrations were evaluated. Vector analysis of astigmatism was performed using Alpins method with the ASSORT software. Results The mean logMAR UDVA in the experimental group was - 0.12 +/- 0.06, - 0.05 +/- 0.08, and - 0.08 +/- 0.08 at 1-week, 1-month, and 3-month follow-up, whereas - 0.05 +/- 0.06, - 0.12 +/- 0.06, and - 0.14 +/- 0.06 in the control group (p = 0.017, p < 0.001, and p = 0.003). At 3-month follow-up, 79% eyes achieved a UDVA of 20/16 or better, 9% gained one line of corrected distance visual acuity, the mean manifest cylinder was - 0.375 +/- 0.254 D, 84% showed a manifest cylinder within +/- 0.50 D, the mean magnitude of difference vector was 0.41 +/- 0.35 D, the mean absolute angle of error (AE) was 7.36 +/- 6.21 degrees, and 41% exhibited an arithmetic AE within +/- 5 degrees in the experimental group, whereas 94%, 19%, - 0.203 +/- 0.148 D, 100%, 0.21 +/- 0.15 D, 3.39 +/- 3.68 degrees, and 69% in the control group (all p < 0.05). The postoperative and preoperative corneal spherical aberrations were comparable in both groups (p > 0.05). Conclusion Primary topography-guided FS-LASIK using Pentacam-measured anterior corneal astigmatism axis exhibited slightly inferior clinical results to that using the manifest refractive astigmatism axis. Both methods achieved comparable postoperative and preoperative corneal spherical aberrations.