Table 1.
The OSCAR-IB quality control criteria for retinal OCT scans.
Table 2.
Pathology of the retina to be considered by the OSCAR-IB criteria.
Table 3.
Comparison of published criteria with the “OSCAR IB” criteria.
Figure 1.
Obvious: The left image is blurred due to poor focusing.
This results in increased noise and loss of transversal resolution in the OCT image on the right.
Figure 2.
Signal: The signal strength for this image is 13 dB which is lower than the limit of 15 dB.
This results in a more noisy OCT image with a lot of speckling.
Figure 3.
Decentration: The ring scan is not correctly centred as can be observed in the left image.
The edge of the optic nerve head crosses more than two circles. Therefore the ringscan is rejected.
Figure 4.
Algorithm failure: The red line in the OCT image right is not clearly at the border of the RNFL.
The location corresponds to inferior of the ONH.
Figure 5.
Retinal pathology: There is severe peri-papillary atrophy.
It can be seen that this affects the RNFL enormously.
Figure 6.
Illumination: The OCT scan here is badly illuminated.
Also here this results in speckling and decrease of resolution.
Figure 7.
Beam placement: the laser beam is not placed centrally.
This can be seen at the outer nuclear layer (ONL). The two arrows point to two regions of the ONL. The left arrow points to a light gray region whereas the other points to a darker gray region. If there is too much difference in colour of the ONL itself a scan is rejected.
Table 4.
Proportion of rejected OCT scans per reader, broken up to each of the seven “OSCAR IB” criteria based on the prospective validation set of 159 OCT scans from Amsterdam, San Francisco and Calgary.