Canon TX-20 Full Auto Tonometer - Manual (Page 82)

82
7Troubleshooting
Warning
Code Cause Remedy
229 Detected over current on the USB device connection.
1) Record the message code, contents (including error
codes) and then execute [OK].
2) Check the connected USB device — it may not be
compatible with the USB standard. Or, connect a USB
device that is compatible with the standard. For details,
contact your sales representative or local Canon dealer.
230
Could not do auto-alignment because could not find eye
within set time period.
The following problems may have occurred:
The patient’s eye is outside the possible range for auto-
alignment.
1) Adjust the measurement unit and the chin rest to position
the entire pupil of the patient’s eye in the monitor.
2) Perform the measurement again.
The patient’s eye moved. Or the eye is nystagmic.
1) Instruct the patient to stare at the eye fixation lamp, confirm
the patient’s eye has stopped moving and then perform
the measurement.
2) If a nystagmus or another problem causes the patient’s
eye to move constantly during auto-alignment, press the
measurement button when the corneal light is clearly
visible. You can perform measurements during auto-
alignment.
However, the positioning alignment may not be accurate.
Note that the measurement may not be accurate when
measuring this way.
Eyelid or eyelashes are blocking the pupil.
1) If the eyelid or eyelashes are blocking the pupil, instruct
the patient to keep his/her eyes wide open until the
measurement is finished.
2) If the patient cannot open his/her eyes, the examiner
should lightly hold the upper eyelid and do the
measurement while helping to lift the patient’s eyelid. Be
careful to not hurt the patient.
Mascara is blocking the pupil.
1) Adjust so the corneal light point appears.
2) Do the measurement again.
The pupil may be dystrophic or deformed. Or, there is a
possibility the patient has undergone iris surgery.
1) Adjust the measurement unit and the chin rest to position
the corneal light point so it appears near the center.
2) Do the measurement again.
A corneal disorder or some other abnormality exists on the
surface of the cornea.
1) Do the measurement in manual alignment mode. However,
an error may occur even in manual alignment mode
depending on the severity.
External light is shining on the patient’s eye.
1) Do not allow bright light or sunlight to shine on the patient’s
eye during measurement.
L-IE-5191C_TX-20.indb 82 2013/07/18 13:10:40