Citation:
Yang Lan, He Yumei, Zhao Fang, et al. Comparison of central corneal thickness measured by different devices in myopic patients[J]. Chin J Exp Ophthalmol,2024,42(9):814-819. DOI: 10.3760/cma.j.cn115989-20220912-00424.
ABSTRACT [Download PDF] [Read Full Text]
Objective To compare the correlation and consistency of central corneal thickness (CCT) measured by four different instruments, specular microscope SP-1P, IOLMaster 700, Pentacam HR and RTVue XR-OCT.
Methods A diagnostic test study was performed.A total of 50 right eyes of 50 consecutive outpatients who planned to undergo corneal refractive surgery at Hanyang Aier Eye Hospital from January to May 2022 were included.CCT was measured with the specular microscope SP-1P, IOLMaster 700, Pentacam HR and RTVue XR-OCT, respectively.The differences of CCT measurements by the four instruments were compared.The correlation and consistency between the CCT values was analyzed by Pearson linear analysis and Bland-Altman test, respectively.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Hanyang Aier Eye Hospital (No.HYEYE20221229JM).Written informed consent was obtained from each subject.
Results The mean CCT values measured by SP-1P, IOLMaster 700, Pentacam HR and RTVue XR-OCT were (522.68±30.08), (544.06±32.85), (541.00±31.75) and (528.86±31.60)μm, respectively, with a statistically significant overall difference ( F=5.09, P=0.002).CCT measurements obtained with SP-1P were lower than those obtained with IOLMaster 700 and Pentacam HR, while the IOLMaster 700 measurements were higher than those of RTVue XR-OCT, showing statistically significant differences (all at P<0.05).Pearson correlation analysis revealed significant positive correlations of CCT measurements between SP-1P and IOLMaster 700, SP-1P and Pentacam HR, SP-1P and RTVue XR-OCT, IOLMaster 700 and Pentacam HR, IOLMaster 700 and RTVue XR-OCT, Pentacam HR and RTVue XR-OCT ( r=0.988, 0.980, 0.988, 0.981, 0.982, 0.973; all at P<0.01).Bland-Altman consistency analysis showed that the 95% limits of agreement (95% LoA) for CCT measurements between SP-1P and RTVue XR-OCT, IOLMaster 700 and Pentacam HR were -16.46-6.14 and -10.56-14.48 μm, respectively, with 3(6%) and 2(4%) data points outside the 95% LoA, respectively.The mean difference lines for the CCT measurements were close to 0, indicating good consistency and clinically acceptable differences without statistical significance.
Conclusions CCT values measured with specular microscope SP-1P and RTVue XR-OCT, as well as those measured with IOLMaster and Pentacam HR, are relatively close in patients with low to moderate myopia, show good consistency and can therefore be considered interchangeable.