Effect of incision on visual outcomes after implantation of a trifocal diffractive IOL

BACKGROUND: To evaluate visual acuity, corneal astigmatism and corneal higher-order aberrations (HOAs) after implantation of trifocal diffractive IOLs operated with either a corneal steep-axis incision or 135° incision. METHOD: This prospective study enrolled patients randomly assigned to different groups. According to preoperative corneal astigmatism, 101 eyes of 77 patients were assigned into group A(1) (0 ~ 0.50 D) or A(2) (0.51 ~ 1.00 D) with a corneal steep-axis incision or group B(1) (0 ~ 0.50 D) or B(2) (0.51 ~ 1.00 D) with a 135° incision. Visual acuity, corneal astigmatism and corneal higher-order aberrations (HOAs) were followed-up for 3 months. RESULTS: Corneal astigmatism in group A(2) significantly decreased 3 months after surgery (P < 0.01) and was significantly lower than that in group B(2) 1 day, 2 weeks, 1 month, and 3 months postoperatively (all values of P < 0.01). The following parameters were better in group A(2) than in group B(2): uncorrected intermediate visual acuity (UIVA) at 1 day, 2 weeks, 1 month, and 3 months (P = 0.00, 0.00, 0.01, 0.01, respectively);uncorrected distance visual acuity (UDVA) at 1 day and 2 weeks (P = 0.00, 0.01); and uncorrected near visual acuity (UNVA) at 1 day, 2 weeks, and 1 month postoperatively (P = 0.00, 0.01, 0.02, respectively). CONCLUSIONS: After a corneal steep-axis incision, patients with preoperative corneal astigmatism of 0.51 D to 1.00 D exhibited reduced corneal astigmatism and achieved better UIVA and early postoperative UDVA/UNVA. TRIAL REGISTRATION: Retrospectively Registered Trials ISRCTN10086721, 23/06/2018.