Zeiss CIRRUS HD-OCT 500, User Manual

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CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Appendix
B-17
A clinical study was conducted with 55 glaucomatous subjects to determine the intra–visit
and inter–visit repeatability of CIRRUS HD-OCT optic nerve head parameters. The study
was performed in two phases. Phase 1 of the study was designed to determine intra–visit
variability, wherein each subject was imaged three times during a single visit on one
CIRRUS HD-OCT by one operator. Phase 2 was designed to determine inter–visit variability,
wherein each subject was imaged on four subsequent visits by one operator.
The study subjects ranged in age from 46 to 87 years; the mean was 70.7 ± 11.1 years. The
glaucomatous subjects were comprised of 26 mild, 11 moderate, and 18 severe cases. The
repeatability and visit–to–visit variability SD and limits for the ONH parameters are shown in
Table B-15 .
Table B-15: Repeatability and Visit–to–Visit Variability of ONH Parameters –
Glaucomatous Subjects
A total of 119 subjects with glaucoma were enrolled in a clinical study conducted at four
sites. Ninety–four subjects with two qualified scans each were included in the analysis, of
which 45 were categorized as mild glaucoma, 20 as moderate glaucoma and 19 as severe
glaucoma. The mean age of the included subjects was 66.9 years, with a range from 43 to
89 years. The repeatability SD and limits for the GCA parameters are shown in
Table B-16 .
1. Derived from Mwanza, JC, Chang, RP, Budenz, DL, Durbin, MK, Gendy, MG, Ski, W, Feauer, WJ. Reproducibility of Peripapillary
Retinal Nerve Fiber Layer Thickness and Optic Nerve Head Parameters Measured with Cirrus HD-OCT in Glaucomatous Eyes.
IOVS 2010; 51:5724-5730.
Repeatability
SD
Repeatability
Limit
a
Visit–to–Visit
Variability SD Visit–to–Visit
Variability
Limit
b
CV%
c
Disc Area
0.084 mm
2
0.233 mm
2
0.084 mm
2
0.233 mm
2 4.4%
Rim Area
0.045 mm
2
0.125 mm
2
0.045 mm
2
0.125 mm
2 6.6%
Average Cup–to–Disc Ratio 0.009 0.025 0.009 0.025 1.2%
Vertical Cup–to–Disc Ratio 0.014 0.039 0.015 0.042 1.9%
Cup Volume
0.032 mm
3
0.089 mm
3
0.063 mm
3
0.175 mm
3 11.7%
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. Visit–to–Visit Variability Limit is the upper 95% limit calculated for the difference between individual measurements.
Per ISO 5725–1 and ISO 5725–6, Visit–to–Visit Variability Limit = 2.8 x Visit–to–Visit Variability SD.
c. Coefficient of Variability is CV = SD divided by the mean.
Note: Operator and device variability were not considered for this study.