ABSTRACT
Objective To compare the ocular parameters measured by 2 biometry devices Tomey OA-2000 and IOLMaster in cataract eyes.Methods A total of 74 cataract patients (74 eyes) were included in this prospective study.Ocular parameters,including axial length (AL),keratometry (K),anterior chamber depth (ACD) and white to white (WTW),were obtained from Tomey OA-2000 and IOLMaster,respectively.Paired t-test was applied to analyze the differences of ocular parameters from Tomey OA-2000 and IOLMaster,while Bland-Altman plot was used to assess the agreement of these ocular parameters.Results The AL,flat K,steep K,mean K,central corneal thickness (CCT),ACD,lens thickness,pupil diameter and WTW values measured by Tomey OA-2000 were (24.26 ± 2.71) mm,(44.09 ± 1.76) D,(45.01 ± 1.73) D,(44.55 ± 1.72)D,(518.41 ±34.18) μm,(3.07 ±0.48)mm,(4.48 ±0.61)mm,(4.07 ±0.95)mm and (11.50 ± 0.52)mm respectively.Values of AL,flat K,steep K,mean K,ACD and WTW from IOLMaster were (24.33 ± 2.69) mm,(44.21 ± 1.74) mm,(45.15 ± 1.76) D,(44.69 ± 1.74) D,(3.04 ± 0.46)mm and (11.65 ± 0.41) mm respectively.The difference values of AL,flat K,steep K,mean K,ACD and WTW between Tomey OA-2000 and IOLMaster were (-0.07 ±0.10) mm (t =-5.99,P＜0.01),(-0.12 ± 0.21) D (t =-4.14,P＜0.01),(-0.14 ± 0.20)D (t =-5.88,P＜0.01),(-0.12 ±0.13) D (t =-7.44,P＜0.01),(0.03 ±0.14) mm (t=1.99,P=0.05) and (-0.14±0.32) mm (t=-3.73,P＜0.01) respectively.The 95％ limits of agreement (LoA) of the AL,flat K,steep K,mean K,ACD obtained from the two devices was 0.27 mm,0.50 D,0.53 D,0.38 D,0.30 mm,respectively,and the agreement was good;95％ LoA of WTW was 0.78 mm,and the consistency was poor.Conclusion The differences of AL,K values and ACD between Tomey OA-2000 and IOLMaster were small,suggesting the agreement is unified.
ABSTRACT
Background The measurement of corneal Q value is essential for corneal refractive surgery and calculation of intraocular lens during cataract surgery.Topolyzer was often used for the measurement of Q value,and recently Topcon KR-1W and iTrace were applied in ophthalmology.However,whether the measured values are interchangeable is unclear.Objective This study was to assess the difference and consistency of corneal Q values measured by Topcon KR-1W,iTrace and Topolyzer.Methods Corneal Q values were measured on 100 right eyes of 100 healthy subjects under the approval of Ethic Committee of the Sixth Hospital Affiliated to Shanghai Jiaotong University and informed consent of each subject from November to December in 2014 with Topcon KR-1W,iTrace and Topolyzer.Three valid measurements were obtained for each device,and the average values from each device were calculated.The difference of the outcomes among the instruments was compared by repeated measures analysis of variance (ANOVA),and the consistency among the outcomes from different apparatus was analyzed by Bland-Altman plots.Results The mean corneal Q values were-0.184-±0.112,-0.117±0.167 and-0.269±0.117 from Topcon KR-1W,iTrace and Topolyzer,respectively,with a significant difference among them (P ＜ 0.001).The measured Q value by Topcon KR-1W was 0.085±0.010 larger than that by Topolyzer,and the Q values by iTrace was 0.152± 0.014 larger than that by Topolyzer,while the Q values obtained by Topcon KR-1W was 0.067±0.016 smaller than that by iTrace (all at P＜0.05).The 95％ confidence interval of the values between Topcon KR-1W and iTrace,Topcon KR-1W and Topolyzer,iTrace and Topolyzer were-0.106 to-0.028,0.060 to 0.109 and 0.118 to 0.186,respectively.Bland-Altman plots showed that 6％,6％ and 5％ values were outside of 95％ agreement of limit (LoA) between Topcon KR-1W and iTrace,iTrace and Topolyzer or KR-1W and Topolyzer,respectively,with the maximal differences of 0.28,0.43 and 0.38.Conclusions Corneal Q values measured by Topcon KR-1W and iTrace are larger than those measured by Topolyzer.Due to the poor agreements among the corneal Q values by the 3 kinds of devices,they are not interchangeable in clinical applications for the measurement of corneal Q value.
ABSTRACT
Background The assessment of total corneal power is essential to both the prediction of intraocular lens power before cataract surgery and the diagnosis of corneal ectasia.Objective This study was to access the repeatability of corneal power measurements in post-laser assisted in-situ keratomileusis (LASIK) eyes with GalileiⅡ dual Scheimpflug analyzer.Methods In this cross-sectional study,68 eyes of 36 subjects who received LASIK surgery more than 3 months in Eye Hospital of Wenzhou Medical University were recruited from July to September in 2011.The mean preoperative spherical equivalent diopter was (-4.95±2.08) D in the subjects with the diopter range from-1.75 D to-10.00 D.The parameters of corneal power were measured by Galilei Ⅱ dual Scheimpflug analyzer,including SimK,Ka,Kp,KG and Kray.Three-time consecutive measurements were completed in every examined eye to obtain the data of SimK,Ka,Kp,KG and Kray,respectively.The coefficient of variation (CV),standard deviation (SD),Cronbach α coefficient and intra-class correlation coefficient (ICC) were calculated to evaluate the repeatability.Concordance between the different measurements was assessed using Bland-Altman agreement analysis.This study followed the Helsinki Declaration,all subjects signed informed consent.Results The CVs of three-time measured SimK,Ka,Kp,KG and Kray were 0.24％,0.28％,-0.37％,0.31％ and 0.32％,respectively,and the Cronbach α values were ＞0.9 and the ICCs were ＞0.982.The Bland-Altman analysis between different measurements showed that the maximum 95％ limits of agreement (LoA) were 0.37 D for SimK,0.46 D for Ka,0.09 D for Kp,0.45 D for KG and 0.49 D for Kray,respectively.Conclusions The Galilei Ⅱ dual Scheimpflug analyzer performed high repeatability and concordance on corneal power measurements in post-LASIK eyes.The differences between measuring results are clinically acceptable.