Optos P200TxE, User Manual, Page: 46 / 84

Chapter 4 - Capture images
1. Select to capture an OCT image.
2. Capture an SLO image if one has
NOT
already been captured (see How to capture SLO images on
page 39).
3. Select to
Follow up to display the previous scans.
4. Select the scan you wish to follow-up.
5. Capture the OCT image in the usual way (see How to capture OCT images on page 43).
Note
l
The patient's previous scans are displayed by date and type.
l
The system will attempt to register the patient's current position against the previous scan
location. You can adjust the location if required (see
Using the hand control on page 33).
4.9 How to check OCT scans
After you have captured your OCT image you should check the scan. You can then delete or accept the
scan.
You should check the following:
l
Scan results.
l
Scan content.
l
Image artifacts.
TABLE 7: Scan results
Result Description
SNR
Scans with SNR indications of 9/10 to 10/10 are optimal SNRs, which produce OCT images
of the highest quality.
Scans with SNR indications of SNR above 7/10 are likely to be acceptable.
Scans with SNR indications of SNR of 6/10 are marginal. You should consider repeating
the scan trying to achieve a higher level of SNR.
Scans with SNR indications of 5/10 or lower should be excluded and retaken.
Movement
Movement detection indicates the extent of eye movement during capture. For example,
12/97 indicates movement detected on 12 scan lines out of the 97 captured.
You should replay the frames and assess if the movement is significant.
Blink
Blink detection indicates the number of frames where the tracking system could not detect
retinal content. For example, 18/65 indicates low signal, likely due to blinking, detected on
18 scan lines out of the 65 captured.
You should replay the frames and assess if this is significant.
Average
Where image averaging is applied the scan result shows the number of scans included. For
example "20/25" indicates 20 scans were included from 25 captured.
Scan
position
error
Scan position errors indicate that the scan position cross reference to the opto map image
could not be established.
You should attempt to recapture the scan.
Page 46 of 84 Part Number: G110230-003-ENG
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