AIM: To evaluate the repeatability of central corneal thickness (CCT) measurement by entacam, and agreement of CCT measured by Pentacam and ultrasound pachymetry (USP) in Chinese myopia. Thereby investigate the possib...AIM: To evaluate the repeatability of central corneal thickness (CCT) measurement by entacam, and agreement of CCT measured by Pentacam and ultrasound pachymetry (USP) in Chinese myopia. Thereby investigate the possibility of Pentacam as a substitute for USP in CCT measurement before refractive surgery. The effects of corneal curvature measured by Pentacam on CCT were also evaluated. METHODS: One hundred and forty-eight right eyes of 148 individual with myopia were included in this study. Three successive Pentacam CCT measurements followed by 10 successive ultrasound pachymetry were carried out in the 148 eyes. Mean of CCT taken by each device was calculated for comparison. According to the CCT measured by USP, all the 148 eyes were divided into 3 groups: <520 mu m, 520-560 mu m, >560 mu m. For all eyes and each group the CCT obtained by Pentacam and USP were compared. Anterior corneal curvature of the 148 eyes was also adopted for correlation analysis with CCT obtained by ultrasound pachymetry. In addition, CCT measurement using 60 random selected Scheimpflug images was performed by 3 skilled investigators at different time, and this was repeated for 3 times by a forth investigator to assess repeatability of Pentacam CCT measurement using Scheimpflug images. RESULTS: Intraclass correlation coefficient (ICC) analysis revealed high intraobserver repeatability (ICC=0.994, F=158.60, P<0.001) for CCT measurement by Pentacam. The interobserver (ICC=0.998, F =494.73, P <0.001) and intraobserver (ICC=0.997, F=383.98, P<0.001) repeatability for Pentacam CCT measurements using Scheimpflug images were also excellent. There was high positive correlation between the CCT values measured by Pentacam and ultrasound pachymetry (r=0.963, P<0.001). Bland-altman plots showed that the Pentacam underestimate the CCT by 8.02 mu m compared with ultrasouond pachymetry.The differences between Pentacam and USP increased as the CCT readings by USP increased (Pentacam vs USP: slope=-0.04, P< 0.05). The 95% upper and lower limits of agreement between CCT values obtained from the two devices were +9. 33 mu m and -25.37 mu m. No significant association could be found between CCT and anterior corneal curvature. CONCLUSION: Inter- and intraobserver variability for CCT measurements by Pentacam was considerably below clinically significant levels. CCT of myopia obtained by Scheimpflug camera, Pentacam, were highly correlated to that by ultrasound pachymetry. However, the values obtained are not directly interchangeable between Pentacam and ultrasound pachymetry as the 95% limits of agreement are relatively wide. Pentacam can be a useful instrument for measuring CCT in candidates to refractive surgery in clinic.展开更多
Dear Editor,I write to present the results of a study on the correlation between the ultrasound energy consumed during phacoemulsification with various preoperative parameters,including best corrected distance visual ...Dear Editor,I write to present the results of a study on the correlation between the ultrasound energy consumed during phacoemulsification with various preoperative parameters,including best corrected distance visual acuity（BCDVA）,the signal to noise ratio（SNR）obtained by partial coherence laser interferometry and primarily,lens spikes measurements derived by A-scan ultrasound biometry.Quantification of crystalline lens hardness before cataract removal has been attempted by several researchers in the past.These have been in humans and in animals,in vivo and in vitro,and have used a variety of imaging modalities.展开更多
Background:To compare the difference in central corneal thickness(CCT)measurements in normal eyes between a rotating Scheimpflug camera combined with a Placido-disk corneal topographer(Sirius,CSO,Italy)and ultrasound ...Background:To compare the difference in central corneal thickness(CCT)measurements in normal eyes between a rotating Scheimpflug camera combined with a Placido-disk corneal topographer(Sirius,CSO,Italy)and ultrasound pachymetry(USP).Methods:A systematic literature search was conducted for relevant studies published on PubMed,Medline,EMBASE,and the Cochrane Library and ClinicalTrials.gov from inception to August 1st,2019.Primary outcome measures were CCT measurements between Sirius and USP.A random effects model was used to pool CCT measurements.Results:A total of twelve studies involving 862 eyes were included in this meta-analysis.The meta-analysis found CCT measurements between Sirius and USP to be statistically significantly different(P<0.0001).The mean difference between Sirius and USP was-11.26μm with a 95%confidence interval(CI)(-16.92μm,-5.60μm).The heterogeneity Was IP=60%(P=0.004).Conclusion:CCT measurements with the Sirius Scheimpflug-Placido topographer were statistically significantly lower than USP.However,it may be argued that the mean difference of 11.26μm is not a clinically significant difference.展开更多
目的：比较Pentacam、IOLMaster和A型超声测量仪测量前房深度（anterior chamber depth,ACD）的准确性。方法：观察性对照研究。对69例（138眼）近视患者由同一操作者分别使用Pentacam、IOLMaster和A型超声测量仪进行ACD测量,并对所得...目的：比较Pentacam、IOLMaster和A型超声测量仪测量前房深度（anterior chamber depth,ACD）的准确性。方法：观察性对照研究。对69例（138眼）近视患者由同一操作者分别使用Pentacam、IOLMaster和A型超声测量仪进行ACD测量,并对所得数据进行统计学分析。3种仪器的测量值一致性比较采用Bland-Altman检验,且用组内标准差及计算重复性系数来评价3种方法的重复性。结果：Pentacam,IOLMaster和A型超声测量仪测得ACD值分别为（3.77±0.24）、（3.73±0.23）、（3.69±0.22）mm。Bland-Altman分析显示,3种方法测量ACD的平均值一致性较好（Pentacam vs IOLMaster：Co A 0.04mm,Lo A-0.05-0.13mm;A超vs IOLMaster：Co A 0.04mm,Lo A-0.17-0.08mm;Pentacam vs A超：Co A 0.08mm,Lo A-0.06-0.22mm）。组内标准差及计算重复性系数显示3种方法测量ACD的重复性好（Sw=0.03、0.02、0.03;2.77 Sw=0.08、0.06、0.08）。3种仪器测量ACD值相互正相关（r=0.946,0.987,0.951,P〈0.001）。结论：Pentacam、IOLMaster和A型超声3种方法测量ACD的可重复性均很好、变异小、高度相关。Pentacam测得的ACD值稍大于A型超声,但由于3组数据可重复性好,变异系数小,故此差异没有重要的临床意义。展开更多
文摘AIM: To evaluate the repeatability of central corneal thickness (CCT) measurement by entacam, and agreement of CCT measured by Pentacam and ultrasound pachymetry (USP) in Chinese myopia. Thereby investigate the possibility of Pentacam as a substitute for USP in CCT measurement before refractive surgery. The effects of corneal curvature measured by Pentacam on CCT were also evaluated. METHODS: One hundred and forty-eight right eyes of 148 individual with myopia were included in this study. Three successive Pentacam CCT measurements followed by 10 successive ultrasound pachymetry were carried out in the 148 eyes. Mean of CCT taken by each device was calculated for comparison. According to the CCT measured by USP, all the 148 eyes were divided into 3 groups: <520 mu m, 520-560 mu m, >560 mu m. For all eyes and each group the CCT obtained by Pentacam and USP were compared. Anterior corneal curvature of the 148 eyes was also adopted for correlation analysis with CCT obtained by ultrasound pachymetry. In addition, CCT measurement using 60 random selected Scheimpflug images was performed by 3 skilled investigators at different time, and this was repeated for 3 times by a forth investigator to assess repeatability of Pentacam CCT measurement using Scheimpflug images. RESULTS: Intraclass correlation coefficient (ICC) analysis revealed high intraobserver repeatability (ICC=0.994, F=158.60, P<0.001) for CCT measurement by Pentacam. The interobserver (ICC=0.998, F =494.73, P <0.001) and intraobserver (ICC=0.997, F=383.98, P<0.001) repeatability for Pentacam CCT measurements using Scheimpflug images were also excellent. There was high positive correlation between the CCT values measured by Pentacam and ultrasound pachymetry (r=0.963, P<0.001). Bland-altman plots showed that the Pentacam underestimate the CCT by 8.02 mu m compared with ultrasouond pachymetry.The differences between Pentacam and USP increased as the CCT readings by USP increased (Pentacam vs USP: slope=-0.04, P< 0.05). The 95% upper and lower limits of agreement between CCT values obtained from the two devices were +9. 33 mu m and -25.37 mu m. No significant association could be found between CCT and anterior corneal curvature. CONCLUSION: Inter- and intraobserver variability for CCT measurements by Pentacam was considerably below clinically significant levels. CCT of myopia obtained by Scheimpflug camera, Pentacam, were highly correlated to that by ultrasound pachymetry. However, the values obtained are not directly interchangeable between Pentacam and ultrasound pachymetry as the 95% limits of agreement are relatively wide. Pentacam can be a useful instrument for measuring CCT in candidates to refractive surgery in clinic.
文摘Dear Editor,I write to present the results of a study on the correlation between the ultrasound energy consumed during phacoemulsification with various preoperative parameters,including best corrected distance visual acuity（BCDVA）,the signal to noise ratio（SNR）obtained by partial coherence laser interferometry and primarily,lens spikes measurements derived by A-scan ultrasound biometry.Quantification of crystalline lens hardness before cataract removal has been attempted by several researchers in the past.These have been in humans and in animals,in vivo and in vitro,and have used a variety of imaging modalities.
基金supported in part by the Foundation of Wenzhou City Science&Technology Bureau(Grant No.Y2020037)Medical and Health Science and Technology Program of Zhejiang Province(Grant No.2019KY111)+1 种基金Zhejiang Provincial&Ministry of Health Research Fund for Medical Sciences(Grant No.WKJ-ZJ-2134)Zhejiang Provincial High-level Talents Program(Grant No.2017-102).
文摘Background:To compare the difference in central corneal thickness(CCT)measurements in normal eyes between a rotating Scheimpflug camera combined with a Placido-disk corneal topographer(Sirius,CSO,Italy)and ultrasound pachymetry(USP).Methods:A systematic literature search was conducted for relevant studies published on PubMed,Medline,EMBASE,and the Cochrane Library and ClinicalTrials.gov from inception to August 1st,2019.Primary outcome measures were CCT measurements between Sirius and USP.A random effects model was used to pool CCT measurements.Results:A total of twelve studies involving 862 eyes were included in this meta-analysis.The meta-analysis found CCT measurements between Sirius and USP to be statistically significantly different(P<0.0001).The mean difference between Sirius and USP was-11.26μm with a 95%confidence interval(CI)(-16.92μm,-5.60μm).The heterogeneity Was IP=60%(P=0.004).Conclusion:CCT measurements with the Sirius Scheimpflug-Placido topographer were statistically significantly lower than USP.However,it may be argued that the mean difference of 11.26μm is not a clinically significant difference.
文摘目的：比较Pentacam、IOLMaster和A型超声测量仪测量前房深度（anterior chamber depth,ACD）的准确性。方法：观察性对照研究。对69例（138眼）近视患者由同一操作者分别使用Pentacam、IOLMaster和A型超声测量仪进行ACD测量,并对所得数据进行统计学分析。3种仪器的测量值一致性比较采用Bland-Altman检验,且用组内标准差及计算重复性系数来评价3种方法的重复性。结果：Pentacam,IOLMaster和A型超声测量仪测得ACD值分别为（3.77±0.24）、（3.73±0.23）、（3.69±0.22）mm。Bland-Altman分析显示,3种方法测量ACD的平均值一致性较好（Pentacam vs IOLMaster：Co A 0.04mm,Lo A-0.05-0.13mm;A超vs IOLMaster：Co A 0.04mm,Lo A-0.17-0.08mm;Pentacam vs A超：Co A 0.08mm,Lo A-0.06-0.22mm）。组内标准差及计算重复性系数显示3种方法测量ACD的重复性好（Sw=0.03、0.02、0.03;2.77 Sw=0.08、0.06、0.08）。3种仪器测量ACD值相互正相关（r=0.946,0.987,0.951,P〈0.001）。结论：Pentacam、IOLMaster和A型超声3种方法测量ACD的可重复性均很好、变异小、高度相关。Pentacam测得的ACD值稍大于A型超声,但由于3组数据可重复性好,变异系数小,故此差异没有重要的临床意义。
