Effect of two different preoperative calculation schemes on visual outcomes of patients after toric intraocular lens implantation

Purpose To compare the postoperative visual outcomes of two different preoperative corneal incision schemes in TECNIS toric intraocular lens (IOL) implantation. Methods In this randomized controlled study, patients with preoperative corneal astigmatism greater than 1.0 diopter (D) were included. These patients were grouped according to the different preoperative schemes: steep-axis group and minimum-residual refractive astigmatism group. The outcome measurements were the residual refractive astigmatism, visual acuity, changes of corneal astigmatism, and high-order aberration at 1 month postoperatively. Results This study consisted of 90 eyes (45 eyes steep-axis group, 45 eyes minimum-residual refractive astigmatism group). 1 month after surgery, the refractive astigmatism was statistically lower in the minimum-residual refractive astigmatism group compared with the steep-axis group (0.58 +/- 0.40D vs 0.38 +/- 0.37D, P = 0.021). The minimum-residual refractive astigmatism group had a smaller difference vector (0.56 +/- 0.38D vs 0.36 +/- 0.35D; P = 0.047) and a smaller prediction error (0.60 +/- 0.44D vs 0.37 +/- 0.35D; P = 0.004). In the steep-axis group, corneal astigmatism significantly decreased compared with preoperative value (1.65 +/- 0.57D vs 1.17 +/- 0.64D; P < 0.001). In the minimum-residual refractive astigmatism group, the changes of corneal astigmatism before and after surgery were not significant. Moreover, total aberration and second astigmatism in ocular aberration were lower in the minimum-residual refractive astigmatism group compared with the steep-axis group (1.86 +/- 1.09 vs 1.37 +/- 0.95; P = 0.035 and 0.47 +/- 0.28 vs 0.31 +/- 0.19; P = 0.015, respectively). Conclusion Minimum-residual refractive astigmatism incision had better astigmatism correction and more accurate prediction. The corneal astigmatism was stable 1 month after surgery. It might lead to better visual quality in the early postoperative stage. Trial registration number for prospectively registered trials: clinicaltrials.gov NCT04006912, 07/02/2019.