Zeiss CIRRUS HD-OCT 500, User Manual

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CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Appendix
B-13
Table B-12: Repeatability and Reproducibility of Area of RPE Elevations
The repeatability and reproducibility SD and limits of the volume of RPE elevations are seen
in
Table B-13 below. The repeatability limit of volume measurements within the 3 mm
circle was higher than that of the 5 mm circle in the 200x200 scans (0.0327 and 0.0275
mm
3
respectively). For the 512x128 scan, the opposite was true, although the difference
was smaller (0.0206 and 0.0245 mm
3
respectively). The reproducibility limit of volume
measurements within the 3 mm circle was higher than that of the 5 mm circle in the
200x200 scans (0.0341 and 0.0298 mm
3
respectively). For the 512x128 scan, the
reproducibility limits for the 5 mm circle was higher than that of the 3 mm circle (0.0288
vs. 0.0235 mm
3
). The repeatability and reproducibility limits will affect the ability to
determine when measurements have changed due to a change in pathology as opposed to
random variability.
Repeatability Reproducibility
Repeatability
SD (mm
2
)
Repeatability
Limit
a
(mm
2
)
Reproducibility SD
(mm
2
)
Reproducibility
Limit
b
(mm
2
)
CV
c
%
200x200 Scan
3mm Circle 0.1295 0.3626 0.1568 0.4389 10.1%
5mm Circle 0.1012 0.2834 0.1455 0.4073 4.9%
512x128 Scan
3mm Circle 0.0837 0.2343 0.0998 0.2794 7.5%
5mm Circle 0.1537 0.4304 0.1936 0.5422 9.6%
a. Repeatability Limit is the upper 95% limit for the difference between repeated results. Per ISO 5725–1 and ISO 5725–6, Repeatability Limit = 2.8
x Repeatability SD.
b. Reproducibility Limit is the upper 95% limit calculated for the difference between individual measurements using different operators and instru-
ments. Per ISO 5725–1 and ISO 5725–6, Reproducibility Limit = 2.8 x Reproducibility SD.
c. CV = Coefficient of variation = SD ÷ Mean.