Clinical Application Of Intraocular Lens Biometrics In Cataract With Macular Diseases

Objective: To compare the accuracy of IOL master and A-scan in the measurement of ocular axis and intraocular lens in cataract patients with macular disease,and to evaluate the postoperative refractive status.Methods: Retrospective case study.38 cases(46 eyes)with macular diseases in affiliated hospital of Gui Zhou medical university from December 2017 to May 2019 underwent cataract surgery.Central retinal thickness(CRT)were measured by OCT.Axial length(AL)were measured by IOL Master and A-scan preoperatively,which were substituted into SRK-T or Haigis formulas to calculate the intraocular lens(IOL)power.Then monofocal foldable IOL were implanted during the surgery.Refraction were measured with a phoropter 3 months postoperatively.The preoperative and the postoperative visual acuity were compared by Wilcoxon rank-sum test.AL and reserved diopter of eyes between IOL Master group and A-scan group were compared by Wilcoxon signed-rank.The consistency of the test results of the two measurement methods were compared by Bland-Altman.The correlation between AL difference value and CRT was compared by Pearson correlation analysis.Mc Nemar paired test was used to analyze the percentage of myopia shift 3 months postoperatively between IOL Master group and A-scan group.Wilcoxon signed-rank was used to compare the absolute error(AE)of IOL Master group and A-scan group in 3 months postoperatively.Results:1、For the cataract patients with macular degeneration,7 eyes(15.2%)had visual acuity less than 0.3,24 eyes(52.2%)had visual acuity of 0.3-0.5 and 15 eyes(32.6%)more than 0.5 three months after the operation,compared with the preoperative visual acuity <0.3 in 21 eyes(45.7%),the visual acuity of 0.3 ～ 0.5 in 18 eyes(39.1%)and ≥0.5 in 7 eyes(15.2%),the difference was statistically significant(Z=-2.457,P=0.014).2、There was no significant difference in AL between the two measurements,and the two measurements were uniform.3、The correlation analysis was carried out between the difference value of the axial length measured by IOL Master and A-scan and the thickness of macular fovea,(r=0.087,P=0.564)and the difference were not statistically significant.4、The median of reserved diopter in the A-scan group and the IOL Master group were-0.18 D and-0.195 D,the reserved diopter of IOL Master group and A-scan group were compared(P=0.067),there was no significant difference.5、There was no significant difference between the two groups in the rate of myopia shift(P>0.05).6、In the IOL Master group,the proportion of AE was 91% in 0～1D and 9% in AE≥1D.In A-scan group.The proportion of AE was 76% in 0～1D and 24% in AE≥1D.The difference was statistically significant(Z=-2.957,P=0.003).Conclusion:1.The visual acuity after cataract surgery was better than pre-operation for patients with cataract and macular disease;2.For cataract patients combined with macular disease,A-scan and IOL Master have consistency in measuring the axial length,which is independent of the thickness of macular fovea;3.The cataract patients with macular diseases after surgery is myopic drift;4.By comparing the distribution characteristics of postoperative refractive error between the two groups of the cataract patients with macular diseases,the biometrics accuracy of IOL Master was better than A-scan.