Assessment Of Toric Iol Alignment With An Aberrometric Corneal Analyzer Using Preoperative Planning Images As Reference

To evaluate the feasibility of aligning OPD-ScanIII (OPD) images with preoperative planning data from the Verion™ Image Guided System to assess toric intraocular lens (IOL) alignment, and to investigate the relationship between IOL misalignment and residual refractive astigmatism.

Tertiary referral center at Hospital das Clínicas, Ribeirão Preto Medical School – University of São Paulo, Brazil.

Patients implanted with Clareon® toric IOLs were examined preoperatively and postoperatively using OPD-Scan III and Verion™ images. Misalignment was defined as the angular difference between the preoperative planned axis (Verion™) and the final IOL axis estimated from retroillumination images. Rotation was defined as the change in IOL orientation between two postoperative time points. Image alignment was performed using episcleral vessel landmarks. Residual refractive astigmatism was analyzed using vector decomposition into Cartesian components (J0 and J45).

Among 56 eyes (44 patients), the mean signed angular difference between Verion™ and OPD images was 0.49° ± 2.90°, and the mean absolute difference was 2.18° ± 1.96°; in 20% of cases, this discrepancy exceeded 4°. The mean IOL misalignment was 6.11° ± 4.57°, while rotation was 2.55° between surgery and 1 week, 1.41° at 4 weeks, and 0.98° at late follow-up. A significant correlation was found between IOL misalignment and the magnitude of residual refractive astigmatism (P < 0.0001). The mean refractive cylinder decreased from –1.38 D preoperatively to –0.57 D postoperatively and remained stable over time.

Alignment of OPD and Verion™ images using episcleral vessel registration is feasible and may enhance the assessment of toric IOL orientation. Misalignment from the intended axis significantly impacts astigmatic outcomes.