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Accuracy of Toric Intraocular Lens Realignment Calculators: A Vector-Based Bivariate Comparison of Current
Klemens P Kaiser1, Jascha A Wendelstein2, Mariam Sobhi1
1From the Department of Ophthalmology (K.P.K., M.S., P.N., T.K., C.M.L.), Goethe-University, Frankfurt am Main, Germany.
American Journal of Ophthalmology
|July 11, 2026
Summary
Three toric intraocular lens (IOL) calculators (AstiFix, Gatinel-TOR, Ophtera-AA) offer consistent axis recommendations for toric IOL realignment, showing no systematic bias. Other methods like TorAlign and IOLCon-LPC had divergent recommendations.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Optics
Background:
- Toric intraocular lenses (IOLs) correct astigmatism but require precise axis alignment.
- Residual astigmatism after cataract surgery necessitates IOL realignment.
- Accurate prediction of astigmatic error is crucial for successful IOL outcomes.
Purpose of the Study:
- To compare the accuracy of available calculation methods for toric IOL realignment.
- To evaluate astigmatic prediction error (PE) using vector and bivariate analysis.
- To assess the consistency of recommended rotation axes for toric IOLs.
Main Methods:
- Retrospective comparative accuracy study involving 49 eyes.
- Calculated predicted post-realignment astigmatism and rotation axes using AstigmatismFix, Gatinel-TOR, Ophtera-AA, TorAlign, and IOLCon-LPC.
- Evaluated astigmatic PE via vector magnitude and bivariate analysis; assessed axis agreement using intraclass correlation coefficients (ICC).
Main Results:
- AstiFix, Gatinel-TOR, and Ophtera-AA demonstrated highly consistent axis recommendations (ICC ≥ 0.997) and low mean vector PE (0.43-0.51D).
- TorAlign showed significantly different axis recommendations (ICC=0.816-0.822), and IOLCon-LPC had the lowest agreement with realignment-specific tools.
- No tested formula showed statistically significant deviation from the zero-vector; repeated pseudophakic measurements did not improve accuracy.
Conclusions:
- Realignment-specific calculators (AstiFix, Gatinel-TOR, Ophtera-AA) using pre-realignment subjective refraction provide reliable and consistent axis recommendations.
- IOLCon-LPC and TorAlign exhibited divergent axis recommendations and higher total variance, indicating less reliability for toric IOL realignment planning.
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