Predictive Analysis Of Different IOL Formulas For Postoperative Refractive Power In Patients With Long Axis Cataract

Objective:To investigate the accuracy of SRK/T formula,HolladayⅠformula,Haigis formula,Barrett UniversalⅡformula and EVO formula in predicting refractive power after long axial cataract surgery.Methods:A total of 135 eyes of 95 patients with axial length（AL）≥26mm who underwent phacoemulsification combined with intraocular lens implantation（Phaco+IOL）in the First Affiliated Hospital of Xinjiang Medical University from July 2019 to January 2022 were collected.According to AL,they were divided into three groups:group A（26mm≤AL<28mm）,group B（28mm≤AL<30mm）,and group C（AL≥30mm）.The mean refractive error（ME）and mean absolute refractive error（MAE）of SRK/T formula,HolladayⅠformula,Haigis formula,Barrett UniversalⅡformula and EVO formula were calculated respectively for statistical analysis.Results:Most of ME_SRK/T,ME_HolladayⅠ,ME_Haigis,ME_BUⅡand ME_EVOwere positive values,indicating that hyperopic drift was common in patients with long axial cataract surgery.There were significant differences in MAE among the five formulas（P<0.01）.Pairwise comparison showed that EVO formula and Barrett UniversalⅡformula had the best prediction accuracy,followed by SRK/T formula and Haigis formula,and HolladayⅠformula was the worst.The percentages of the five formulas within the refractive threshold range of 0.5D and 1.0D were compared,and the MAE_HolladayⅠpercentage was also the lowest.Spearman rank correlation analysis showed that the prediction accuracy of SRK/T formula,HolladayⅠformula,Haigis formula,and Barrett UniversalⅡformula decreased with the extension of AL（rs>0,P<0.05）.The EVO formula had good prediction stability and was less affected by AL（P>0.05）.Conclusion:Hyperopia drift is common in patients with long axial cataract after surgery,and the refractive error further increases with the prolongation of AL.The prediction accuracy of Barrett UniversalⅡand EVO formula is comparable to and better than SRK/T formula,HolladayⅠformula and Haigis formula,and EVO formula is the least affected by AL,so it is more recommended to use EVO formula in IOL calculation of patients with long axial cataract.