AUTHOR=Chu Yi-Ching , Huang Tzu-Lun , Chang Pei-Yao , Ho Wei-Ting , Hsu Yung-Ray , Chang Shu-Wen , Wang Jia-Kang 

TITLE=Predictability of 6 Intraocular Lens Power Calculation Formulas in People With Very High Myopia

JOURNAL=Frontiers in Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2022.762761

DOI=10.3389/fmed.2022.762761

ISSN=2296-858X

ABSTRACT=Purpose
To investigate the accuracy of 6 intraocular lens (IOL) power calculation formulas in predicting refractive outcome in extremely long eyes.

Setting
Department of Ophthalmology, Far Eastern Memorial Hospital, Taiwan

Design
Retrospective comparative study

Methods
In this retrospective single-center study, we reviewed 70 eyes of 70 patients with axial length (AL) ≥ 28 mm who received uneventful 2.2-mm corneal wound phacoemulsification and IOL in-the-bag placement. The actual postoperative refractive results were compared to the predicted refraction calculated with 6 formulas (Haigis, Hoffer Q, Holladay 1, SRK/T, T2, Barrett Universal II formulas) using IOLMaster 500 as optical biometry in User Group for Laser Interference Biometry (ULIB) constants.  
 
Results
Over all, the Haigis and Barrett formulas achieved the lowest level of mean prediction error (PE) and median absolute error (MedAE). The Hoffer Q, Holladay 1, SRK/T, and T2 produced hyperopic prediction errors (p < 0.05). The Hoffer Q and Holladay 1 had significantly more MedAE between 6 formulas. After the mean PE have been zeroed out, the MedAE had no significant difference between each group. The absolute error tends to be larger in longer AL. The absolute errors were 30.0-37.1% and 60.0-64.3% within 1.0 D of all patients compared to predicted refraction calculated in various formulas.

Conclusion
In conclusion, the Haigis and Barrett universal II formulas had a better trend of in predicting IOL power in high myopic eyes with AL longer than 28 mm using ULIB constant in this study.  The postoperative refractive results were inferior to the benchmark standards, which indicated the precision of IOL power calculation in high myopes still required improvement.