Factors Affecting Cirrus-HD OCT Optic Disc Scan Quality: A Review with Case Examples

Figure 8

Incorrect axial alignment. Cirrus HD-OCT retinal nerve fiber layer (RNFL) thickness maps ((a)-(b)), RNFL deviation maps ((c)-(d)), horizontal ((e)-(f)), and circular ((g)-(h)) tomograms from two eyes. Left panels: partial truncation of the inner retinal layers; note the black areas of missing data on the RNFL thickness map (a), the corresponding clusters of “superpixels” on the RNFL deviation map (c), and the retinal nerve fiber layer segmentation artifact ((g) arrows). Right panels: partial truncation of the optic disc cup (f); note the algorithm failure to detect the optic disc (see (b), (d), and (f) and compare with the corresponding left panels). Thus, the scan circle was automatically placed in the center of the image, resulting in inferior scan circle displacement ((d) double arrows).

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(h)