A-Scan Operation and Use
Section 3
3 - 6
MANUAL
MODE
The user can select Manual Mode by
continuously pressing the [
MODE
] key until
“Manual” is displayed. This mode allows the
user to identify and accept an echo pattern based
on their clinical judgment and not use the pattern
recognition software within the instrument.
When using the Manual Mode, the user can
position the gates after freezing the image, by
pressing the [
GATES
] key repeatedly until the
desired gate is flashing and then positioning that
gate using the joystick on the right side of the
instrument.
The user is also able to select the number of
gates required depending on the eye type. This
can be accomplished once manual mode is
selected by pressing the [
#GATES
] key located
just below the mode key in the upper right
corner of the display until the desired number of
gates is displayed.
IMMERSION TECHNIQUE
In addition to direct contact measurements, a
water immersion technique may be used with the
EZ-S
CAN
in order to completely eliminate
concerns over corneal compression skewing
results. The technique requires the use of an
immersion scleral shell as described below using
the automatic capture examination mode.
1.
Examination Mode
. Ensure the correct
examination mode is selected as indicated in
the upper right corner of the Measure
Screen. The examination mode may be
changed by touching the mode button until
the desired mode is shown. The following
examination modes are available:
¾
Cataract
¾
Dense Cataract
¾
Aphakic
¾
Pseudophakic
¾
Manual Mode
3.
Tissue Velocity
. Ensure the appropriate
tissue velocities are selected by pressing the
[TVEL]
key once the examination MODE
has been selected.
Table 3-2
Default Tissue Velocities
Structure
Velocities
ACD 1532
m/s
Natural Lens
1641 m/s
Vitreous 1532
m/s
PMMA Lens (Pseudophakic)
2720 m/s
Acrylic Lens (Pseudophakic)
2120 m/s
Silicone-I Lens (Pseudophakic)
980 m/s
Silicone-II Lens (Pseudophakic)
1090 m/s
The tissue velocity may be changed by first
touching the
[ TVEL ]
button to display the
Tissue Velocity Screen (see Figure 3-6).
Touch the
[ TVEL# ]
button to edit the
desired tissue velocity, enter the appropriate
number, and touch the
[ ENTER ]
button.
Verify that the tissue velocity has changed
before returning to the Measure Screen by
pressing
[DONE]
.
In Pseudophakic Mode, the user can also
select a “Custom” lens by pressing the
[TVEL]
key and then selecting
[CUSTOM
LENS]
. Press
[ADD LENS]
and type the
Lens Name followed by
[ENTER]
. Type
the axial correction (if known) followed by
[
ENTER
] (if not known, simply press
[
ENTER
]; then type the correct velocity
followed by [
ENTER
].
3.
Immersion Option
. Ensure that the
immersion option is ON as indicated on the
[IMMER]
selection key. The immersion
option may be toggled between ON and OFF
by touching the
[ IMMER ]
key. A small
white “GATE” will appear on the left side of
the baseline.
If the probe is aligned in the
shell correctly, the corneal echo should
appear in the center of this gate.
