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. Author manuscript; available in PMC: 2022 Oct 1.
Published in final edited form as: Ophthalmology. 2021 Apr 2;128(10):1426–1437. doi: 10.1016/j.ophtha.2021.03.036

Table 1.

Definition of Artifacts

Artifact Definition
Eye movement Thin horizontal or vertical white lines leading to loss of integrity of the vessels on the en-face angiogram in conjunction with interruption, displacement, doubling or ghosting of vessels, and/or quilting defect. This type of artifact can result in duplication or removal of some parts of retinal vessels from the scan. This artifact was classified as severe if it affected more than 10% of the total B-scans comprising the en-face angiogram.
Defocus Decrease in reflective intensity and clear visualization of the details of small vessels on the angiogram. Mostly results from decreased reflectance intensity scores in the entire B-scans comprising the angiogram. This artifact was classified as severe if it affected more than 10% of the total B-scans comprising the en-face angiogram.
Shadow Decreased intensity of retinal layers in isolated areas, often owing to vitreous floaters or corneal opacities. As a result, these structures cannot be clearly visualized and are replaced with dark areas in the en-face angiogram. This artifact was classified as severe if it affected more than 10% of the total B-scans comprising the en-face angiogram.
Decentration Translocation of the center of the optic nerve head (ONH) or macula from the center of the en-face angiogram to the periphery of the scan. The OCTA algorithm may or may not be able to correctly identify the new center of the ONH or macula. This artifact was classified as severe if it resulted in loss of more than 10% in any adjacent retinal sectors of the ONH or macula.
Segmentation error Erroneous identification of the borders of superficial vascular layer by the automated segmentation algorithm resulting in a deviation of more than 50% of the total thickness diameter in a B-scan. This artifact was classified as severe if it was observed in more than 10% of total B-scans comprising the en-face angiogram.
Blink Total loss of reflectance intensity in an area of adjacent B-scans because of a blink during the scan capture. It results in horizontal or vertical black lines on the en-face angiogram. This artifact was classified as severe if it affected more than 5% of the total B-scans comprising the en-face angiogram.
Z offset Loss of the peripheral borders of B-scans (obtained in both horizontal and vertical raster pattern) due to malalignment of head position during scan capture. This type of artifact happens if the display of a B-scan falls out of the operator window for scan acquisition while capturing the scan. This artifact was classified as severe if it affected more than 5% of the total B-scans comprising the en-face angiogram.