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N. Alfonsi, I. Brunette, J.–F. Laliberte, J.–M. Legeais, G. Renard, J.–L. Bourges; Pachymetry With The Pentacam Oculus Topograph : Accuracy, Repeatability And Reproducibility In Normal Central And Mid Periphery Corneas . Invest. Ophthalmol. Vis. Sci. 2006;47(13):1329.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the accuracy, repeatability and reproducibility of central and mid–peripheral pachymetries obtained with the Pentacam Oculus (PO) Scheimpflug camera topographic system, using ultrasound pachymetry (USP) as a gold standard
Both eyes of 22 normal subjects (mean age 37 ± 11 years, 3 males) were tested. On visit A, observer 1 (NA) acquired 3 PO elevation maps before measuring corneal thickness in nine different locations with the USP: central (C), superior (S), nasal–superior (NS), nasal (N), nasal–inferior (NI), inferior (I), temporal–inferior (TI), temporal (T) and temporal–superior (TS). Three successive USP measurements were obtained at each location. On visit B (within one to six weeks from visit A) observers 1 and 2 (NA, JLB) acquired 3 PO elevation maps. The order of the visits, observers, and eyes were randomized. Intraclass Correlations Coefficients (ICC) analysis was performed to study the PO performance.
Repeatability of the three successive measurements performed during the same visit was substantial to almost perfect. Average ICC values were 0.940 (0.706 to 0.989) for right eyes (OD) and 0.948 (0.835 to 0.992) for left eyes (OS). The lowest ICCs were obtained for the superior measurements (S, NS and TS). Compared to USP "true" values, the PO accuracy was almost perfect for all locations. ICCs ranged from 0.863 to 0.993 with an average of 0.933 for OD and from 0.891 to 0.988 with an average 0.936 for OS. Central pachymetries yield the highest ICC values. Inter–observer agreement was demonstrated to be almost perfect with ICCs above 0.985 for both eyes in all locations. Reproducibility with time (2 visits) was almost perfect with ICCs ranging from 0.900 to 0.988 (average 0.96) for OD and from 0.930 to 0.980 (average of 0.936) for OS. ICC scores were lower in the superior cornea. Superior measurements also showed more variability. This may be due to the eyelid pressure on the eye globe.
The Pentacam topographer allows accurate and reproducible pachymetry measurements in normal eyes and could safely replace the USP assessment.
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