| Objective:1.To study the repeatability and reproducibility of the datum obtained from volunteers by the Pentacam system.2.By the Pentacam system,examining the anterior segment of the myopia people,to assesss the clinic useful of the Pentacam system.3.Comparing the central corneal thickness obtained by the Pentacam system with the datum obtained by A-ultrasound pachymeter,to analysis the agreement of the datum of these two measures.4.Comparing the datum of the corneal thickness post-LASIK seven days by the Pentacam system with the estimating datum,to assess the function of the Pentacam system to follow up the corneal thickness post-LASIK.Method:1.By the Pentacam system,to measure the anterior segment of 46 volunteers 3 times,the first and the second datum by same observer being the intro-observer group,and the first and the third datum by two observers being the inter-observers group.To study the repeatability and reproducibility of the datum obtained by the Pentacam system from the volunteers with Paired-Samples T tests and Bland-Altman plots.2.By the Pentacam system,measuring anterior segment of 219 myopia people(436 eyes),the datum were divided into three groups according to the spherical equivalent,eye and sex,and the datum of the anterior segment were analysised with the One-way ANOVA to the spherical equivalent group and 2 Independent Samples Tests to the eye group and the sex group.3.Comparing corneal central thickness values obtained by the Pentacam system with that by A-ultrasound pachymeter from the 219 myopia people(436 eyes),to discuss the ability of exchangeable corneal thickness datum obtained by these two systems with Paired-Samples T tests and Bland-Altman plots.4.Comparing the datum of the corneal thickness post-LASIK seven days by the Pentacam system with the estimating datum,to assess the function of the Pentacam system measuring the corneal thickness post-LASIK.Result:1.In the intro-observer group,all correlation coefficients were higher than 0.9. There was statistically significant difference in the datum of the anterior chamber volume(P＜0.05).Bland-Altman plots were created to assess the difference in the intro-observer group and all datume were better in the 95%limits of agreement, with the mean of difference all centering around zero.In the inter-observers group, all correlation coefficients were higher than 0.9,except the correlation coefficient of the pupil diameter was 0.878.There was statistically significant difference in the datum of the anterior chamber volume and the anterior chamber depth(P＜0.05).Bland-Altman plots were created to assess the difference in the inter-observers group,and the datum were better in the 95%limits of agreement, with the mean of difference all centering around zero.2.Coefficient of variation of the datum of the corneal anterior Km,corneal posterior Km,corneal central thickness,corneal apex thickness,corneal thinnest thickness,corneal volume and anterior chamber depth were lower than those of anterior chamber angle,pupil diameter and anterior chamber volume.The anterior chamber angle of the super high myopia group was narrower than the datum of other myopia groups,there was statistically significant difference(P＜0.05).The corneal anterior Km of the super high and the high myopia groups were higher than the datum of other myopia groups,there were statistically significant difference(P＜0.05).The corneal volume of male and female,there was no statistically significant difference(P＞0.05).The corneal anterior Km of female was higher than that of male,there was statistically significant difference(P＜0.05).There were statistically significant difference(P＜0.05),between the other datum of male and female,the datum of male were higher than that of female. Between the right and left eyes,the datum were no statistically significant difference(P＞0.05).3.All correlation coefficients of the corneal thickness were higher than 0.9, between the Pentacam system and A-ultrasound pachymeter.There were statistically significant difference in the datum of the corneal central thickness and the corneal apex thickness(P＜0.05),and the datum of corneal central thickness and the corneal apex thickness by the Pentacam system were higher than those by A-ultrasound pachymeter.There was no statistically significant difference, between the data of the corneal thinnest thickness by the Pentacam system and A-ultrasound pachymeter(P＞0.05).Bland-Altman plots were created to assess the difference in the inter-measures,the datum of the corneal thinnest thickness was better in the 95%limits of agreement,with the mean of difference centering all around zero,and the datum of the corneal central thickness and the corneal apex thickness were good in the 95%limits of agreement,with the mean of difference centering around zero.4.Comparing the datum of the corneal thickness post-LASIK seven days by the Pentacam system with the estimating datum post-LASIK,all real datum post-LASIK were lower than the estimating datum,and there were good in the 95% limits of agreement between two measues' datum from the Bland-Altman plots.Conclution:1.The repeatability and reproducibility of the Pentacam system is good.2.The Pentacam system is easy to use and faster than others used in the clinic. But,the function of getting the datum of anterior chamber angle was limited,as the principle of the Pentacam system and the anterior chamber anatomy of the eye.3.The agreement of accuracy of the Pentacam system and A-ultrasound pachymeter was good,and the Pentacam system was better than the A-ultrasound pachymeter in observing the whole corneal thickness change.4.Between the datum of the corneal thickness obtained by the Pentacam system post-LASIK seven days and the estimating datum,the agreement was good.The Pentacam system can be used to follow up the corneal thickness post-LASIK.
|
PDF Full Text Request