Appendix
2660021169012 Rev. A 2017-12
CIRRUS HD-OCT User Manual
A-32
Table A-7 Disc Size Classification from the Sample Population
Factors that Affect 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
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. Only age and optic disc area were used when applying
normative limits to ONH parameters.
Age
The CIRRUS Asian RNFL Normative Database was developed utilizing 315 subjects aged 19
to 79. Disc Area and Cup Volume showed no effect of Age. CD Ratio (average and vertical)
increased slowly with age (slope = +0.002 per year, R
2
= 0.0133, p = 0.0409 for average
CD Ratio, slope = +0.0011 per year, R
2
= 0.011, p = 0.03 for vertical CD Ratio).
Optic Disc Area
The distribution of disc area for the normative database eyes is discussed in the paragraph
above. Note that 90% of disc areas were between 1.3 mm
2
and 2.5 mm
2
. Therefore,
normal limits will not be well defined for this population outside of those disc sizes, and
are not applied (gray is shown for not applicable instead of the usual color coding). All
optic nerve head parameters increase with disc size, including Rim Area (slope = +0.24
mm
2
of rim per mm
2
of disc, R
2
= 0.13, p = 0.042), Cup Volume (slope = +0.25 mm
3
of
cup per mm
2
of disc, R
2
= 0.39, p = 0.011), and Cup to Disc Ratios (slope = +0.35 per
mm
2
of disc, R
2
= 0.35, p < 0.001 for average CDR, slope = +0.29 per mm
2
of disc, R
2
=
0.34, p < 0.001 for vertical CDR).
Ethnicity
The ethnicity breakdown of the CIRRUS RNFL Normative Database is as follows: 44%
Chinese, 44% Japanese and 12% Indians. Only thirteen subjects (less than 5%) had discs
larger than 2.5 mm
2
in the study eye. Ten subjects (less than 5%) had discs smaller than
1.3 mm
2
. There was no statistically significant difference among different ethnicities with
respect to the Rim Area (p = 0.16) or the Disc Area (p = 0.38).
Disc Size
Classification
Smallest 1/3 of Discs Medium 1/3 of Discs Largest 1/3 of Discs
Disc Area
< 1.7 mm
2
1.7 mm
2
to 2.0 mm
2
> 2.0 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 ...