Purpose:This prospective cohort study aimed to assess the influence of tear film stability on corneal refractive power measurement and surgical planning in cataract patients.Methods:Participants were divided into tear...Purpose:This prospective cohort study aimed to assess the influence of tear film stability on corneal refractive power measurement and surgical planning in cataract patients.Methods:Participants were divided into tear film instability(tear film stability level 2)and control(level 0–1)groups based on Keratograph 5M results.Using IOL Master 700,two consecutive measurements were obtained with a 10-min interval.Parameters including standard keratometry(Kf,Ks and K),keratometric corneal astigmatism(KCA),total keratometry(TKf,TKs and TK)and total corneal astigmatism(TCA)were recorded.IOL power was calculated using SRK-T,SRK-T TK,Haigis,Haigis TK,Barrett Universal II,and Barrett Universal II TK formulas.Results:The results showed significantly higher differences between two measurements in Kf,K,KCA,TKf,TK,and TCA,as well as the vector variability of corneal astigmatism in the tear film instability group(all P<0.05).Of all formulas,only the SRK-T formula displayed significantly higher variability in IOL power calculations in the tear film instability group compared to the control group(P<0.05).Conclusions:This study highlights that tear film instability can lead to deviations in corneal refractive power and astigmatism measurements,contributing to increased prediction errors in IOL power calculation,particularly with the SRK-T formula.展开更多
Purpose:To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens(IOL)calculation.Methods:The keratometric astigmatism measured by Lenstar LS 9...Purpose:To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens(IOL)calculation.Methods:The keratometric astigmatism measured by Lenstar LS 900(KCA_(L)),keratometric astigmatism(KCAp)and total corneal astigmatism(TCA)measured by Scheimpflug camera(Pentacam HR)were documented and analyzed accordingly.Three deduction models using different parameters were compared.Model 1:KCA_(L)+keratometric comeal surgically induced astigmatism(KCSIA,0.30 D@50°);Model 2:KCA_(P)+KCSIA);Model 3:TCA 4-total CSIA(TCSIA,0.23 D@50°).The prediction errors of each model as the difference vector between the actual and the intended residual astigmatism were compared.Results:Seventy-six eyes implanted with toric multifocal IOLs were included in this study.The vector differences of the actual KCSIA and TCSIA were statistically significant in the total sample and against-the-rule(ATR)subgroup(both P<0.05).Model 1 deduced the smallest mean values of prediction error,while that of Model 3 were smaller than that of Model 2,both in the total sample and the ATR subgroups(all P<0.05).Meanwhile,in the total sample and ATR subgroups,the centroid vector magnitudes of Model 3 were smaller than that of Model 1(0.31±0.76 D and 0.39±0.76 D).Conclusions:The calculation of toric multifocal IOL should be individualized especially in the ATR eyes for the impact of PCA on the estimation of the preoperative comeal astigmatism and the CSIA.展开更多
基金supported by the 2022 Science and Technology Project of Tianjin Binhai New Area Health Commission(2022BWKQ008)Tianjin Medical University"Clinical Talent Training 123 Climbing Plan"and Tianjin Medical University Eye Hospital High-level Innovative Talent Programmer(YDYYRCXM-E2023-05).
文摘Purpose:This prospective cohort study aimed to assess the influence of tear film stability on corneal refractive power measurement and surgical planning in cataract patients.Methods:Participants were divided into tear film instability(tear film stability level 2)and control(level 0–1)groups based on Keratograph 5M results.Using IOL Master 700,two consecutive measurements were obtained with a 10-min interval.Parameters including standard keratometry(Kf,Ks and K),keratometric corneal astigmatism(KCA),total keratometry(TKf,TKs and TK)and total corneal astigmatism(TCA)were recorded.IOL power was calculated using SRK-T,SRK-T TK,Haigis,Haigis TK,Barrett Universal II,and Barrett Universal II TK formulas.Results:The results showed significantly higher differences between two measurements in Kf,K,KCA,TKf,TK,and TCA,as well as the vector variability of corneal astigmatism in the tear film instability group(all P<0.05).Of all formulas,only the SRK-T formula displayed significantly higher variability in IOL power calculations in the tear film instability group compared to the control group(P<0.05).Conclusions:This study highlights that tear film instability can lead to deviations in corneal refractive power and astigmatism measurements,contributing to increased prediction errors in IOL power calculation,particularly with the SRK-T formula.
基金the Science&Technology Development Fund of Tianjin Education Commission for Higher Education[2017KJ214]the High-level Innovative Talent Program for Young Scholar of Tianjin Medical University Eye Hospital[YDYYRCXM-C2018-01]+2 种基金the Tianjin Key Medical Discipline(Specialty)Construction Projectthe National Natural Science Foundation of China[81900846]the Tianjin Health Science and technology project[ZC20207].
文摘Purpose:To investigate the influence of posterior corneal astigmatism on the prediction accuracy of toric multifocal intraocular lens(IOL)calculation.Methods:The keratometric astigmatism measured by Lenstar LS 900(KCA_(L)),keratometric astigmatism(KCAp)and total corneal astigmatism(TCA)measured by Scheimpflug camera(Pentacam HR)were documented and analyzed accordingly.Three deduction models using different parameters were compared.Model 1:KCA_(L)+keratometric comeal surgically induced astigmatism(KCSIA,0.30 D@50°);Model 2:KCA_(P)+KCSIA);Model 3:TCA 4-total CSIA(TCSIA,0.23 D@50°).The prediction errors of each model as the difference vector between the actual and the intended residual astigmatism were compared.Results:Seventy-six eyes implanted with toric multifocal IOLs were included in this study.The vector differences of the actual KCSIA and TCSIA were statistically significant in the total sample and against-the-rule(ATR)subgroup(both P<0.05).Model 1 deduced the smallest mean values of prediction error,while that of Model 3 were smaller than that of Model 2,both in the total sample and the ATR subgroups(all P<0.05).Meanwhile,in the total sample and ATR subgroups,the centroid vector magnitudes of Model 3 were smaller than that of Model 1(0.31±0.76 D and 0.39±0.76 D).Conclusions:The calculation of toric multifocal IOL should be individualized especially in the ATR eyes for the impact of PCA on the estimation of the preoperative comeal astigmatism and the CSIA.
