Zeiss CIRRUS HD-OCT 500, Руководство пользователя

Страница: 305 / 352

CIRRUS HD-OCT User Manual 2660021169012 Rev. A 2017-12
Appendix
A-31
Table A-5 CIRRUS Ganglion Cell Analysis Summary Parameters for Normal Asian Study
Eyes ( μ m)
Normal Values for Asian ONH Measurements
CIRRUS ONH parameters are described in "Optic Nerve Head Normative Database:
Diversified" on page A-9 . They include:
• Rim Area (in units of mm
2
)
• Average cup to disc ratio (ratio of cup area to disc area)
• Vertical cup to disc ratio (ratio of cup height to disc height at the cup center)
• Cup Volume (in units of mm
3
)
Note that disc area is calculated and presented, but not compared to normal limits.
In addition, the plot of neuroretinal rim (NR) thickness around the disc is compared to
normative limits.
The descriptive statistics for each optic nerve head parameter are reported in
Table A-6 ,
below.
Table A-6 CIRRUS ONH Summary Parameters for Normal Asian Study Eyes
The disc area is of particular interest. 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
. Disc area showed no dependence on subject age. Classifying disc size as small,
medium or large has been previously done (see example, Spaeth), but typically the sizing
was based on a vertical diameter measured from the slit–lamp. By measuring the disc area
we consider all meridians.
Table A-7 serves as a very general size classification guide
based on dividing the normative data into thirds. One third of the database had discs of 1.7
mm
2
or smaller, one third had discs between 1.7 and 2.0 mm
2
, and the remainder had
discs larger than 2.0 mm
2
.
Parameters Mean SD Minimum Maximum
Average Thickness 83.2 5.3 67.8 99.5
Minimum Thickness 80.9 5.4 63.8 95.2
Temporal–Superior Thickness 82.2 5.6 65.0 99.0
Superior Thickness 84.6 5.9 62.0 102.0
Nasal–Superior Thickness 85.8 5.9 70.0 103.0
Nasal–Inferior Thickness 83.0 5.9 66.0 105.0
Inferior Thickness 80.7 6.0 65.0 98.0
Temporal–Inferior Thickness 82.8 5.5 70.0 102.0
Rim Area
(mm
2
)
Disc Area
(mm
2
)
Average CD
Ratio
Vertical CD
Ratio
Cup Volume
(mm
3
)
Minimum 0.75 1.15 0.06 0.05 0.00
Maximum 2.27 3.14 0.78 0.77 0.73
Average 1.29 1.87 0.51 0.48 0.16
Standard Deviation 0.21 0.36 0.15 0.15 0.14