| Objective:To compare the accuracy of the SRK-Ⅱ,SRK-T,and Barrett Universal II formulas in predicting IOL degrees under different axial lengths.Method:This study was a retrospective clinical analysis.The axial lengths of the patients who were operated with the cataract surgery were divided into four groups:the short axial group(AL≤22mm),the normal axial group(22mm<AL≤24.5mm),the long axial group(24.5mm < AL≤26mm),the ultra-long axial group(AL > 26mm),According to the SRK-Ⅱ,SRK-Tand Barrett Universal II,to calculate the predicted refractive power of each formula,to select the IOL power individually and to implant it in the eye,One month after operation,the refractive status was followed up,and the actual diopter was converted according to the equivalent spherical lens.The accuracy of the three formulas was evaluated by calculating the average refractive error,the average absolute refractive error and the percentage of the number of eyes in different refractive thresholds combined with the axial length.Results:In the short axial group,the MAE with the three formulas was not statistically significant(P>0.05),but the MAE of SRK-Ⅱ was the smallest.In the normal axial group,the MAE with the three formulas was not statistically significant(P>0.05).In the long axial group,the MAE with the SRK-Ⅱ and Barrett Universal Ⅱ is statistically significant differences(P<0.05),but there is not differences between the SRK-T,the SRK-Ⅱand the Barrett UniversalⅡ(P>0.05).In the ultra-long axial group,the differences of MAE between the SRK-Ⅱ,the SRK-T and Barrett UniversalⅡ were statistically significant(P<0.05),but the differences with the SRK-T and the Barrett UniversalⅡ was not statistically significant(P>0.05),and the MAE of the Barrett UniversalⅡ was the smallest in the long axial group and the ultra-long axial group.AE of the SRK-II is positively correlated with AL and K,but it has no correlation with ACD.AE of the SRK-T is not correlated with AL,and it has negatively correlated with ACD,and it is positively correlated with K.AE of the Barrett Universal Ⅱ is negatively correlated with AL,ACD,and it is positively correlated with K.Conclusion:In the short axial group,the accuracy of the SRK-Ⅱ is better.In the normal axial group,the accuracy of the three formulas is equivalent.In the long axial and the ultra-long axial group,the accuracy of the SRK-T and the Barrett UniversalⅡare accurate.The accuracy of Barrett Universal Ⅱ is better than the SRK-T.The postoperative refractive status of the cataract patients is not only related to the IOL calculation formula but also affected by AL,ACD and K. |
