Clinical Accuracy of 18 IOL Power Formulas in 241 Short Eyes

ABSTRACT

Purpose

To analyze the accuracy of 18 intraocular lens (IOL) power calculation formulas in eyes with axial length (AL) ≤ 22 mm.

Methods

We analyzed 241 eyes of 241 patients. Eighteen formulas were evaluated: Barrett Universal II (BUII), EVO 2.0, Haigis, Hoffer Q, Holladay 1 and 2, Cooke K6, Kane, LadasSuperFormula AI, Naeser 2, Olsen, Panacea, Pearl-DGS, RBF 2.0, SRK/T, T2, VRF and VRF-G. Optical biometry was performed with an IOLMaster 700 (Carl Zeiss Meditec, Jena, Germany). With lens constants optimized for the whole range of AL, the mean prediction error (PE) and its standard deviation (SD), the median absolute error (MedAE), the mean absolute error (MAE) and the percentage of eyes with PEs within ±0.25 D, ±0.50 D and <±1.00 D were calculated.

Results

Post-hoc analysis of the absolute PE revealed statistically significant differences (P < .05) between some of the newer formulas (K6, Kane, Naeser 2, Olsen and VRF-G), which obtained the lowest MedAE (respectively, 0.308, 0.300, 0.277, 0.310 and 0.276 D) and the remaining ones. These formulas yielded also the highest percentage of eyes with a PE within ±0.50 D (70.54%, 72.20%, 71.37%, 70.95% and 73.03%, respectively), whereas Panacea and SRK/T yielded the lowest percentage (62.24%), with a stastically significant difference (P < .05) with respect to most formulas.

Conclusion

In eyes with AL ≤22.0 mm, new formulas (K6, Kane, Naeser 2, Olsen and VRF-G) offer the most accurate predictions of postoperative refraction.

KEYWORDS:

• IOL power
• formulas
• IOLMaster
• calculation
• axial length

Disclosure statement

Dr. Voytsekhivskyy is the inventor and sole owner of the VRF and VRF-G formulas and has a patent on the method of estimation of postoperative lens position (ELP) and the calculation of optical power and is the author and copyright holder of a computer program ViOL Commander.

Dr. Hoffer licenses the registered trademark name Hoffer® to ensure accurate programming of his formulas to Carl Zeiss-Meditec (IOLMasters), Haag-Streit (LenStar/EyeStar), Heidelberg Engineering (Anterion), Movu (Argos), Nidek (AL-Scan), Oculus (Pentacam AXL),Tomey (OA-2000), Topcon EU/Visia Imaging (Aladdin), Ziemer (Galilei G6) and all A-scan biometer manufacturers.

Dr. Savini has received personal fees from Alcon, CSO, Oculus and Zeiss.

Dr. Tutchenko declares no potential conflict of interest.

Dr. Hipólito-Fernandes declares no potential conflict of interest.

We have disclosed those interests fully to Taylor & Francis, and have in place an approved plan for managing any potential conflicts arising from this arrangement.

Additional information

Funding

The contribution of IRCCS Fondazione Bietti was supported by Italian Ministry of Health and Fondazione Roma.