Toric IOL positioning with a no-touch head-up display axis alignment
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To compare a new no-touch alignment technique for toric intraocular lenses (IOL) with the conventional technique that uses a manual pendulum.
In this retrospective case–control study, patients who underwent toric IOL implantation using two different alignment techniques (digital Callisto® system vs. manual-pendulum-based marking) were compared in a vector analysis using the Alpins method and an analysis of variance regarding corrected and uncorrected visual acuity and the deviation of the achieved IOL axis from the targeted axis.
Sixty-one eyes were included into analysis. Thirty-six of these surgeries were performed via the Callisto® system and 25 eyes via pendulum-based corneal markings. Median IOL axis misalignment was 3° in both groups. Median uncorrected distance visual acuity was 0.097 logMAR versus 0.200. Median best-corrected visual acuity was 0.000 logMAR versus 0.097. All these data were below the range of statistical significance (p > 0.05). Vector analysis showed no significant difference for TIA [median of 3.14 diopters (D) vs. 2.73 D], SIA (median of 3.82 D vs. 3.79 D), DV (1.18 D vs. 1.08 D), and CI (1.23 vs. 1.29). Median angle of error was 1.96° versus − 0.44° (p > 0.05).
We found no significant difference in the refractive results, the IOL positioning, and the best-corrected and uncorrected distance visual acuity between the two compared methods. Nevertheless, the Callisto® IOL alignment system delivers a standardized and easy-to-use technology. In particular, less-experienced surgeons might benefit from this marking technique.
KeywordsCataract Astigmatism Toric IOL Callisto Pendulum
No funding was received for this research.
Compliance with ethical standards
Conflict of interest
All authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the local ethics committee of the University of Freiburg (vote no. 432/16) and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent was not needed due to the retrospective nature of the study.
- 15.R Core Team (2019) R: a language and environment for statistical computing. https://www.R-project.org