Guoji Yanke Zazhi (Dec 2013)
Comparison of central corneal thickness measured by three optical measurement devices with ultrasound pachymetry
Abstract
AIM:To compare the difference and correlation of central corneal thickness(CCT)measured by Zeiss Visante Anterior Segment Optical Coherence Tomography(Visante OCT), Heidelberg Slit-Lamp Anterior Segment Optical Coherence Tomography(SL-OCT), OrbscanⅡz Computerized Topography(OrbscanⅡz )and A-mode ultrasound pachymetry.METHODS:Forty-three patients with myopia(86 eyes)were included. Sequential measurements of CCT was performed by the same operator with two different anterior segment OCT devices(VisanteTM, Carl Zeiss, Meditec and Heidelberg EngineeringTM), OrbscanⅡz Computerized Topography(Bausch and Lomb IncTM)and A-mode ultrasound pachymetry. The consistency of measurements was statistically analyzed by one-way ANOVA and LSD pair-wise comparisons. The differences were analyzed by Pearson correlation coefficients.RESULTS:The average CCT measured by Visante OCT, SL-OCT, OrbscanⅡz, and A-mode ultrasound pachymetry were(521.05±29.88)μm,(533.73±31.83)μm,(534.02±32.96)μm, and(540.60±31.11)μm, the 95% confidence interval were(514.57～527.54),(526.83～540.65),(533.85～547.35),(536.75～544.45). There was statistically significant difference of CCT between using of Visante OCT and SL-OCT(P=0.009). There was statistically significant difference of CCT using of Visante OCT and A-mode ultrasound pachymetry(PP=0.008). The Visante OCT CCT measurements was significantly less than CCT with SL-OCT(12.69±9.32)μm. Compare with A-mode ultrasound pachymetry and OrbscanⅡz, the Visante OCT measurements significantly underestimated central corneal thickness by a mean of(19.55±8.64)μm and(12.96±12.21)μm. There was no significant difference of CCT between using of SL-OCT and A-mode ultrasound pachymetry(P=0.158), OrbscanⅡz(P=0.954). There was no significant difference of CCT between using of OrbscanⅡz and A-mode ultrasound pachymetry(P=0.176). There were positive correlationship among Visante OCT, SL-OCT, OrbscanⅡz, and A-mode ultrasound pachymetry in CCT measurement(PCONCLUSION:There are excellent correlationship among Visante OCT, SL-OCT,OrbscanⅡz, and A-mode ultrasound pachymetry in CCT measurement. The data shows that the CCT obtained by SL-OCT and OrbscanⅡz do not have significant difference as compared with that from the A-mode ultrasound pachymetry. Three optical measurement devices is more likely to be accepted by patients because of its non-contact, non-invasive, and short measurement time as compared with the A-mode ultrasound pachymetry.
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