31
PERFORMING A
-
SCANS (IMMERSION)
WARNING:
Exercise caution when coming into contact with a patient
’
s eye. To avoid
potential injury, use minimal pressure when applying the immersion shell or adjusting its
position. Only make minor position adjustments while in contact with the eye. If significant
position adjustment is necessary, remove the probe from the eye and then reapply.
WARNING:
Before each procedure, the ultrasound probe and immersion shell must be
cleaned and disinfected. Refer to the
Cleaning and Disinfection
section.
NOTE:
Refer to the
Alignment Ranking System
and
Video Buffer Full
sections for more
information on these topics.
1.
Create a new patient or select an existing patient on the Patient Screen.
2.
Select the A
-
Scan Screen tab. Then select the eye to be measured (OD or OS) by clicking
the
[CHANGE EYE]
†
button.
3.
Select the
“
Immersion
”
radio button on the right
-
hand side of the screen. Select the name
of the Operator performing the measurement from the drop
-
down box.
NOTE:
If the operator is not listed in the
“
Operator
”
drop
-
down box, add the new operator
by selecting
Preferences > Operator
and clicking the [
NEW]
button.
4.
Select the correct Lens and Vitreous type for the eye to be measured.
5.
Gently insert the A
-
Scan probe into the clean and disinfected immersion shell until it
reaches the auto
-
stop point. Verify that the transducer tip is even with the line scored on
the barrel of the shell. Once the probe is properly inserted, tighten the white nylon set
screw to hold the probe in place. Do not overtighten the set screw. Measurements cannot
be performed if the probe is not in the proper position.
6.
Connect the catheter tubing to the immersion shell filler port and to the saline reservoir
(either a syringe or bottle). Place the saline reservoir in a convenient location, typically near
the patient
’
s head, on their chest or shoulder.
7.
Seat or recline the patient in a position comfortable for both Patient and Operator. The
patient
’
s head must be in a nearly horizontal plane and head movement must be minimized
during the exam. Anesthetize the eye and have the patient fixate with both eyes on a spot
on the ceiling or wall.
8.
To Start scanning
†:
-
Click the
[START SCAN]
button; or
-
Press the
Space Bar
(on the keyboard); or
-
Press the
Foot Pedal
(Single Pedal accessory); or
-
Press the
Left Foot Pedal
(Double Pedal accessory)
A waveform will be displayed on the screen, but the unit will not begin recording.
9.
Stabilize the hand holding the probe/immersion shell to minimize excessive movement.
Typically, this can be done by resting a palm on the cheek or forehead of the patient.
10.
Direct the patient to look upward. Pull the patient
’
s lower eye lid down and insert the flared
rim inside the lid. The lower portion of the shell will make contact with the sclera while the
upper part of the shell will be held away from the eye. Then direct the patient to look
straight ahead with the other (uncovered) eye, back toward the fixation point. Lift the
patient
’
s upper eyelid and gently pivot the upper portion of the shell into the upper fornix,
making sure by close inspection that it is in the fornix and not atop a fold in the conjunctiva.
This pivotal motion avoids contact with the cornea and insures centration of the device
around the limbus.
†
This command may be executed through voice control. Refer to the
A
-
Scan Voice Controls
section.
