To determine patient factors and eye conditions associated with artifacts in Spectralis optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) scans.

Retrospective cross-sectional study.

The prevalence of 12 artifact types were described in this review of 2313 eye scans from 1188 patients who underwent a complete eye examination with Spectralis OCT scanning during the period of September 2009 to July 2013. The generalized estimating equations model was used to analyze associations between increased artifact prevalence and 10 patient characteristics, which included age, sex, race, visual acuity, refractive error, astigmatism, cataract status, glaucoma staging, visual field reliability, and glaucoma diagnosis.

A total of 1070 or 46.3% of the 2313 eye scans had at least 1 artifact. Decentration error was the most common artifact (27.8%), followed by posterior vitreous detachment artifacts (14.4%). Visual acuity of less than 20/40 (P < .0001), presence of moderate to severe cataracts (P < .0001), advanced stage of glaucoma (P < .0001), and a diagnosis of open-angle glaucoma (P = .0003) were associated with increased prevalence of artifacts.

Clinicians should first assess scans for artifacts before making therapeutic decisions based on RNFL thickness measurements.