Refractive and Visual Outcome of Misaligned Toric Intraocular Lens After Operative Realignment.

Purpose: The study was performed to evaluate the refractive and visual outcome of patients with misaligned toric intraocular lenses (IOLs) after operative realignment, with and without back-calculation of the toric axis after implantation of the IOL.

Design: Institutional, retrospective case-control study.

Methods: This is a retrospective case series of 39 patients who underwent a second operation to realign a misaligned toric IOL from August 2013 to December 2019 at the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Ideal toric axis was calculated using the back-calculator astigmatismfix.com.

Results: The study consists of 39 treated eyes (20 [51%] right eyes). The toric IOLs showed a postoperative misalignment of 25.69 ± 26.06°. Postrotational, uncorrected distance visual acuity (UDVA) improved from 0.39 ± 0.29 logMAR to 0.27 ± 0.18 logMAR. Refractive outcome showed a reduction of residual sphere and cylinder. The postoperative UDVA when performing alignment to the preoperative calculated axis (51%) was 0.24 ± 0.16 logMAR with a cylinder of 0.90 ± 0.90 diopter (D). In the group with alignment to a back-calculated axis (49%), the UDVA was 0.32 ± 0.20 logMAR with a cylinder of 0.76 ± 0.72 D. High cylinder power IOLs (≥2 D) showed a higher decrease in residual cylinder when back-calculation was performed than low cylinder power IOLs (<2 D) (27% vs 9%). The mean spherical equivalent prediction error of the back-calculator was 0.54 ± 0.55 D.

Conclusion: Realignment of misaligned toric IOLs improves visual acuity and reduces residual refractive errors. Especially for high cylinder power IOLs, better refractive outcome can be seen when performing a back-calculation before realignment.