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Evaluation of Reliability of Formulas for Intraocular Lens Power Calculation After Hyperopic Refractive Surgery
Rosa Boccia1, Michele Lanza1, Giuseppe Luciano1
1Multidisciplinary Department of Medical, Surgical and Dental Specialities, Università della Campania Luigi Vanvitelli, 80132 Naples, Italy.
Journal of Clinical Medicine
|March 27, 2025
Summary
The Shammas formula (SF) showed less accuracy in intraocular lens (IOL) power calculation for cataract surgery patients with prior hyperopic laser surgery compared to Barrett True-K No History (BTKNH) and EVO 2.0 formulas.
Area of Science:
- Ophthalmology
- Refractive Surgery
- Biomedical Engineering
Background:
- Evaluating intraocular lens (IOL) power calculation accuracy is crucial for successful cataract surgery.
- Prior hyperopic laser refractive surgery presents unique challenges for standard IOL power calculation formulas.
- Accurate IOL power calculation is essential for achieving desired refractive outcomes post-cataract surgery.
Purpose of the Study:
- To compare the accuracy of five different IOL power calculation formulas in patients who underwent cataract surgery after previous hyperopic laser refractive surgery.
- To identify the most accurate formula for IOL power calculation in this specific patient cohort.
- To provide guidance on formula selection for optimizing refractive outcomes in complex cases.
Main Methods:
- A retrospective, monocentric study reviewed 107 patients who had undergone cataract surgery and prior hyperopic laser refractive surgery.
- Five IOL power calculation formulas were evaluated: Barrett True-K No History (BTKNH), EVO 2.0 Post-Hyperopic LASIK/PRK (EVO 2.0), Haigis-L, Pearl-DGS, and Shammas (SF).
- Mean Absolute Prediction Error (MAE) was calculated for each formula, with subgroup analysis based on axial length and keratometry.
Main Results:
- The Shammas formula (SF) demonstrated significantly less accuracy (p < 0.05) compared to the BTKNH and EVO 2.0 formulas.
- No significant differences in MAE were found between Haigis-L, EVO 2.0, Pearl-DGS, and BTKNH formulas.
- The study included 107 eyes, with exclusion criteria for other ocular/systemic diseases or surgical complications.
Conclusions:
- No single formula showed a clear advantage in standard cases for IOL power calculation after hyperopic laser surgery.
- The Shammas formula (SF) should be avoided in eyes where precise refractive targets are mandatory.
- Formula selection requires careful consideration in eyes with prior refractive surgery to minimize refractive surprises.
