Segmentation errors and motion artifacts in OCT-A associated with epiretinal membranes.

OBJECTIVE

To explore segmentation errors, image quality, and motion-associated artifacts in eyes with idiopathic epiretinal membrane (ERM).

METHODS

This is a prospective observational study. We included 39 eyes affected by ERM and 40 eyes from age-matched healthy subjects. Optical coherence tomography-angiography (OCT-A) was performed in both groups. Segmentation was automatically performed by intergraded software. Segmentation was regarded as inaccurate if either border deviated from the correct plane by more than 50 μm. Presence of motion artifacts (blink lines, displacement, stretch artifacts, quilting, vessel doubling) and image quality index were reported.

RESULTS

Quality index score was 7.2 ± 0.9 for the ERM patients. Phakic eyes with ERM had quality index score of 7.71 ± 1.06, and pseudo-phakic eyes with ERM had a quality index score of 7.32 ± 0.85 (p = 0.22). Motion artifacts were 1.22 ± 0.7 in the study cohort. Segmentation was accurate in all healthy subjects (n = 40). Segmentation errors occurred in 64.1% of ERM patients. The inner plexiform layer was the segmentation boundary most prone to inaccurate segmentation, followed by the internal limiting membrane. Segmentation of retinal pigment epithelial layer was accurate in 96.7% of all cases.

CONCLUSIONS

OCT-A image quality cannot be accurately reproduced in pathological conditions, such as in ERM patients, and is prone to motion artifacts and segmentation errors. Incorrect segmentation results in anatomically incorrect en-face OCT-A images and subsequently in false quantification measures.