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RNFL and ONH Normative Databases
CIRRUS HD-OCT User Manual
The ONH and RNFL OU Analysis supports the clinician in identifying areas of the RNFL that
may be of clinical concern by comparing the measured RNFL thickness to age–matched
data in the CIRRUS RNFL Normative Databases. Normative data that is age–matched to
the patient appears when you perform the
8-28
on patients at least 18 years old. Data was not collected from subjects less than 18
years old.
The same data used to develop the RNFL Database was re–processed to develop normal
limits for optic nerve head parameters. As described further in
Normative Database: Diversified" on page
matched to the disc area of the eye as well as the age of the patient.
The RNFL Normative Database uses a white–green–yellow–red color code, as seen in the
legend at left, to indicate the normal distribution percentiles. The color code applies to
each particular A-scan location in the TSNIT thickness graphs, to the quadrant, clock hour
and whole–circle averages, and to the OD and OS columns of the data table. Among
same–age individuals in the normal population, the percentiles apply to each particular
RNFL thickness measurement along the Calculation Circle as follows:
• The thinnest 1% of measurements fall in the red area. Measurements in red are
considered outside normal limits (red ≤ 1%, outside normal limits).
• The thinnest 5% of measurements fall in the yellow area or below
(1% < yellow ≤ 5%, suspect).
• 90% of measurements fall in the green area (5% < green ≤ 95%).
• The thickest 5% of measurements fall in the white area (white > 95%).
NOTE: Clinicians must exercise judgment in the interpretation of the normative data. For
any particular measurement, note that 1 out of 20 normal eyes (5%) will fall below green.
Interpretation of the 1st Percentile: Values color–coded as "1st percentile" are lower than
99% of the database sample, but may not extrapolate well to the general population with
less than 300 subjects in the reference database. Results falling in this region should be
interpreted with caution.Interpretation of the 5th Percentile: Values color–coded as "5th
percentile" are lower than 95% of the database sample. The 95% Confidence Interval on
the 5th Percentile extends from the 2.5th percentile to the 7.7th percentile of the normative
database.
Information icons
on the Analysis screen offer additional information about the
normative database limits. Hovering over the icon will display a tooltip, and clicking the
icon allows you to create a report of the additional information presented by selecting Print
Preview or Export to DICOM. See
10-15
for more information.
NOTE: Normative data colors will not appear if the patient is less than 18 years old.
"ONH and RNFL OU Analysis" on page
"Optic Nerve Head
A-9, the ONH normative data is
"Normative Data Details Reports" on page
2660021169012 Rev. A 2017-12
A-15
Appendix
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