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CIRRUS HD-OCT User Manual
2660021169012 Rev. A 2017-12
Appendix
A-11
Results
The descriptive statistics for each optic nerve head parameter are reported in
below.
1
Table A-1 Normal Values for CIRRUS ONH measurements in the Sample Population
The disc area is of particular interest. Only eleven subjects (less than 5%) had discs larger
than 2.5 mm
2
in the study eye. Eleven subjects (less than 5%) had discs smaller than 1.3
mm
2
. Disc area showed no dependence on subject age. Classifying disc size as small,
medium or large has been previously done (see example, Spaet
2
, but typically the sizing
was based on a vertical diameter measured from the slit–lamp. By measuring the disc area
we consider all meridians.
serves as a very general size classification guide
based on dividing the normative data into thirds. One third of the database had discs of
1.58 mm
2
or smaller, one third had discs between 1.58 and 1.88 mm
2
, and the remainder
had discs larger than 1.88 mm
2.
Table A-2 Disc Size Classification from the Sample Population
Factors that Affect CIRRUS ONH Normative Ranges
The normal ranges described above do not take into account differences that may be
present due to age, ethnicity, axial length, refraction, optic disc area, or signal strength. In
multiple regression analysis, we found that optic disc area and age were the two
parameters with the greatest effect on the remaining ONH parameters. Based on R
2
values,
disc area explains as much as 40% of the variability in some parameters, while age
explains no more than 5%. All other continuous parameters, such as refractive error and
axial length, explain less than 7% of variability. For these reasons, only age and optic disc
area were used when applying normative limits to ONH parameters.
1 Knight, OJ, Oakley, JD, Durbin, MK, Callan, TM, Budenz, DL “Cirrus Normative Database Study Group: Effect of Ethnicity, Age,
and Axial Length on Optic Nerve Head Parameters Measured by Cirrus™ HD-OCT,” ARVO abstract 2010.
2 Spaeth, GL, Henderer, J, Steinmann, W “The disc damage likelihood scale: its use in the diagnosis and management of glau-
coma,” Highlights Ophthalmol 31: 4-16, 2003.
Rim Area
mm
2
Disc Area
mm
2
Average
CDR
Vertical
CDR
Cup
Volume
mm
3
Minimum
0.720
1.003
0.071
0.058
0.000
Maximum
2.272
2.925
0.812
0.762
0.796
Average
1.311
1.769
0.458
0.435
0.137
Standard Deviation
0.218
0.340
0.173
0.166
0.134
Disc Size
Classification
Smallest 1/3
of Discs
Medium 1/3 of Discs
Largest 1/3 of
Discs
Disc Area
< 1.58 mm
2
1.58 mm
2
to 1.88 mm
2
> 1.88 mm
2
Summary of Contents for CIRRUS HD-OCT 500
Page 1: ...2660021156446 B2660021156446 B CIRRUS HD OCT User Manual Models 500 5000 ...
Page 32: ...User Documentation 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 2 6 ...
Page 44: ...Software 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 3 12 ...
Page 58: ...User Login Logout 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 4 14 ...
Page 72: ...Patient Preparation 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 5 14 ...
Page 110: ...Tracking and Repeat Scans 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 6 38 ...
Page 122: ...Criteria for Image Acceptance 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 7 12 ...
Page 222: ...Overview 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 9 28 ...
Page 256: ...Log Files 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual 11 18 ...
Page 308: ...Appendix 2660021169012 Rev A 2017 12 CIRRUS HD OCT User Manual A 34 ...
Page 350: ...CIRRUS HD OCT User Manual 2660021169012 Rev A 2017 12 I 8 ...
Page 351: ...CIRRUS HD OCT User Manual 2660021169012 Rev A 2017 12 ...