Application of total keratometry in ten intraocular lens power calculation formulas in highly myopic eyes

Background:The accuracy of using total keratometry(TK)value in recent IOL power calculation formulas in highly myopic eyes remained unknown.Methods:Highly myopic patients who underwent uneventful cataract surgery were prospectively enrolled in this prospective comparative study.At one month postoperatively,standard deviation(SD)of the prediction errors(PEs),mean and median absolute error(MedAE)of 103 highly myopic eyes were back-calculated and compared among ten formulas,including XGboost,RBF 3.0,Kane,Barrett Universal II,Emmetropia Verifying Optical 2.0,Cooke K6,Haigis,SRK/T,and Wang-Koch modifications of Haigis and SRK/T formulas,using either TK or standard keratometry(K)value.Results:In highly myopic eyes,despite good agreement between TK and K(P>0.05),larger differences between the two were associated with smaller central corneal thickness(P<0.05).As to the refractive errors,TK method showed no differences compared to K method.The XGBoost,RBF 3.0 and Kane ranked top three when considering SDs of PEs.Using TK value,the XGboost calculator was comparable with the RBF 3.0 formula(P>0.05),which both presented smaller MedAEs than others(all P<0.05).As for the percentage of eyes within±0.50 D or±0.75 D of PE,the XGBoost TK showed comparable percentages with the RBF 3.0 TK formula(74.76%vs.66.99%,or 90.29%vs.87.38%,P>0.05),and statistically larger percentages than the other eight formulas(P<0.05).Conclusions:Highly myopic eyes with thinner corneas tend to have larger differences between TK and K.The XGboost enhancement calculator and RBF 3.0 formula using TK showed the most promising outcomes in highly myopic eyes.

Accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes:a meta-analysis

Background:To compare the accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes.Methods:We searched the databases on PubMed,EMBASE,Web of Science and the Cochrane library to select relevant studies published between Jan 1st,2009 and Aug 11th,2019.Primary outcomes were the percentages of refractive prediction error within±0.5 D and±1.0 D.Results:The final meta-analysis included 16 studies using seven common methods(ASCRS average,Barrett True-K no history,Double-K SRK/T,Haigis-L,OCT formula,Shammas-PL,and Wang-Koch-Maloney).ASCRS average yielded significantly higher percentage of refractive prediction error within±0.5 D than Haigis-L,Shammas-PL and WangKoch-Maloney(P=0.009,0.01,0.008,respectively).Barrett True-K no history also yielded significantly higher percentage of refractive prediction error within±0.5 D than Shammas-PL and Wang-Koch-Maloney(P=0.01,P<0.0001,respectively),and a similar result was found when comparing OCT formula with Haigis-L and Shammas-PL(P=0.03,P=0.01,respectively).Conclusion:The ASCRS average or Barrett True-K no history should be used to calculate the intraocular lens power in eyes after myopic laser refractive surgery.The OCT formula if available,can also be a good alternative choice.

Accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes:a meta-analysis

Background:To compare the accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes.Methods:We searched the databases on PubMed,EMBASE,Web of Science and the Cochrane library to select relevant studies published between Jan 1st,2009 and Aug 11th,2019.Primary outcomes were the percentages of refractive prediction error within±0.5 D and±1.0 D.Results:The final meta-analysis included 16 studies using seven common methods(ASCRS average,Barrett True-K no history,Double-K SRK/T,Haigis-L,OCT formula,Shammas-PL,and Wang-Koch-Maloney).ASCRS average yielded significantly higher percentage of refractive prediction error within±0.5 D than Haigis-L,Shammas-PL and Wang,Koch-Maloney(P=0.009,0.01,0.008,respectively).Barrett True-K no history also yielded significantly higher percentage of refractive prediction error within±0.5 D than Shammas-PL and Wang-Koch-Maloney(P=0.01,P<0.0001,respectively),and a similar result was found when comparing OCT formula with Haigis-L and Shammas-PL(P=0.03,P=0.01,respectively).Conclusion:The ASCRS average or Barrett True-K no history should be used to calculate the intraocular lens power in eyes after myopic laser refractive surgery.The OCT formula if available,can also be a good alternative choice.