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(Visante^TM, Carl Zeiss, Meditec and Heidelberg Engineering^TM), OrbscanⅡz Computerized Topography(Bausch and Lomb Inc^TM)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(P<0.01), OrbscanⅡz(P=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(P<0.01).

CONCLUSION: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.