Effect Of Anterior Chamber Depth On The Choice Of Intraocular Lens Calculation Formula In Patients With Normal Axial Length

Objective:To compare the accuracy of?five intraocular lens calculation formulas(Haigis,SRKⅡ,Hoffer Q,Holladay1 and SRK/T)and to compare the effect of different anterior chamber depths among the IOL formulas in cataract patients with normal axial length(AL).Methods:Case-control study.91 patients with normal AL who underwent uncomplicated cataract surgery were involveded in this analysis.This study was performed in the Department of Ophthalmology at the Affiliated Hospital of Qingdao University from January 2016 to October 2017.According to the depth of anterior chamber(ACD)measured by IOLMaster,45 cases were involveded in shallow anterior chamber group(ACD≤2.70mm)and46caseswereinvolvededinthenormal group(2.70mm<ACD≤3.50mm).The IOLMaster was used to predict the refractive outcomes for five formula.Actual postoperative refractions were taken on 1 month after surgery.Refractive error and absolute refractive error were Calculated.The SPSS19.0was used for statistical analysis to compare the refractive errors,absolute refractive errors and the refractive error distribution of different IOL formulas.Results:In normal AL patients with ACD≤2.70mm,mean refractive error(ME)of Haigis,SRKⅡ,HofferQ,Holladay 1 and SRK/T were-0.13±0.76D,-0.20±0.78D,-0.34±0.74D,-0.33±0.73D and-0.31±0.72D,respctively,and the difference was statistically(F=9.951,P=0.000).ME of the Haigis formula(-0.13±0.76D)differed significantly from Hoffer Q formula(-0.34±0.74D,P=0.000),Holladay1 formula(-0.33±0.73D,P=0.000)and SRK/Tformula(-0.31±0.72D,P=0.001).In normal AL patients with 2.70mm<ACD≤3.50mm,ME of Haigis,SRKⅡ,Hoffer Q,Holladay1 and SRK/T were-0.14±0.68D,-0.16±0.72D,-0.13±0.64D,-0.16±0.64D and-0.15±0.65D,respctively,and there was no significant differences among them(F=0.101,P=0.982).In shallow ACD group,the mean absolute refractive error(MAE)were 0.58±0.50D,0.62±0.49D,0.62±0.51D,0.61±0.51D and 0.58±0.53D with Haigis,SRKⅡ,Hoffer Q,Holladay1,and SRK/T formulas,respectively,and there was no significant differences among them(χ~2=4.027,P=0.402).In normal group,MAE of Haigis,SRKⅡ,Hoffer Q,Holladay1 and SRK/T were 0.53±0.44D,0.60±0.42D,0.49±0.43D,0.51±0.40D and0.53±0.41D,respectively,and there was no significant differences among them(χ~2=4.111,P=0.391).In shallow anterior chamber group,there was no significant difference in the distribution of refractive error between different IOL formulas(χ~2=3.782,P=0.872).In normal group,there was no significant difference in the distribution of refractive error between different IOL formulas(χ~2=5.103,P=0.746).Conclusions:The Haigis formula can predict refraction in shallow anterior chamber patients with normal axial length with less error.The prediction accuracy of Haigis,Hoffer Q,SRKII,Holladay1 and SRK/T is comparable in normal AL patients with normal anterior chamber.According to the preoperative ACD to choose the IOL formula,the postoperative refractive error can be reduced.In the shallow anterior chamber group,the MAE of Holladay1 formula(r=-0.319,P=0.033)and SRK/T formula(r=-0.364,P=0.014)showed a significant positive correlation with the ACD;in the normal group,the MAE of Holladay1 formula(r=0.364,P=0.031)and SRK/T formula(r=0.336,P=0.023)showed a significant positive correlation with the ACD.