ORIGINAL RESEARCH article
Front. Med.
Sec. Ophthalmology
Comparative Evaluation of Intraocular Lens Power Calculation Formulas in Patients After Radial Keratotomy
Provisionally accepted
- Beijing Tongren Hospital, Beijing Ophthalmology and Visual Science Key Lab, Capital Medical University, Beijing, China
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Objective: Assessing the comparative performance of five intraocular lens (IOL) calculation methodologies in cataract patients with previous radial keratotomy (RK) history, with particular attention to axial length (AL)-related and corneal curvature-related formula efficacy. Methods: Five calculation formulas were utilized to determine anticipated refractive outcomes. Discrepancies between predicted and actual outcomes were quantified through comparison of formula-derived spherical equivalents with manifest refraction measurements, generating prediction error (PE) and absolute error (AE) metrics. Additional statistical analysis examined correlations between formula-specific spherical equivalent deviations and biometric parameters including AL and corneal curvature. Results: Barrett True-K and Hoffer QST showed minimal prediction bias (PE: −0.06D and −0.07D; P > 0.05). PEARL-DGS had the best stability (SD: 0.97) and led in ±0.25D accuracy (20.8%, P = 0.665). In AL subgroups, Barrett True-K showed superior accuracy for medium-long eyes (26.0–30.0 mm; PE closest to zero), while EVO 2.0 had the highest hyperopic error in short AL eyes (<26.0 mm). Significant negative correlations between flat keratometry and prediction error were identified for the Hoffer QST, Kane, and Pearl DGS formulas (all P < 0.01). In eyes with flat keratometry < 39.0 D, EVO 2.0, Kane, and Pearl DGS exhibited statistically significant hyperopic biases, while Barrett True-K and Hoffer QST maintained accuracy without systematic error. Conclusion: For cataract patients with previous radial keratotomy, the Barrett True-K formula exhibits enhanced accuracy in IOL power calculation. While newer AI-based formulas show potential, they exhibit a systematic hyperopic bias, limiting their current applicability in this population.
Keywords: accuracy, formula, Intraocular lens, Intraocular lens power, Radial keratotomy
Received: 28 Nov 2025; Accepted: 22 Jan 2026.
Copyright: © 2026 Li, Wang, Yu, Wu, Jia, Yue, Chen, Zhang and Song. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Xudong Song
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