Purpose: To evaluate the quality, reliability, and popularity of videos relating to glaucoma on YouTube. Design: Retrospective, cross-sectional study of YouTube videos about glaucoma. Participants: One hundred YouTube videos were analyzed for this study. Methods: An online YouTube search for glaucoma videos was conducted simulating a user search using the keywords glaucoma, high eye pressure, and high intraocular pressure. The first 100 videos were analyzed, and each video was evaluated by 2 independent reviewers using the modified DISCERN (scale, 1-5), Journal of the American Medical Association (JAMA; scale, 0-4), and Global Quality (GQ; scale, 1-5) criteria to assess quality and reliability. Videos were categorized further into 3 groups depending on the source of their upload. Group 1 comprised videos uploaded by academic or government institutions, group 2 comprised videos uploaded by private medical practices, and group 3 comprised videos uploaded by independent users. Main Outcome Measures: Modified DISCERN, JAMA, and GQ scores for quality and reliability of information and video power index (VPI) for video popularity. Results: No substantial difference in scoring was observed between the 2 independent reviewers. The overall mean +/- standard error (SE) scores were modified DISCERN score, 3.81 +/- 0.06; JAMA score, 2.93 +/- 0.07; and GQ score, 3.98 +/- 0.06. The overall mean +/- SE VPI score was 9.9 +/- 2.9. Significant positive correlations were found between video popularity and quality of information for all 3 criteria (P < 0.05). The videos in groups 1 and 2 showed higher modified DISCERN scores than those in group 3, but did not score higher with either the JAMA or GQ criteria. Videos in group 3 were the most popular when compared with videos in groups 1 or 2 (P < 0.01). Conclusions: Overall, many of the videos had adequate quality and reliability scores. No difference was found among groups 1 through 3 for 2 of the 3 criteria used, suggesting a similar quality of information provided among academic, private, and independent sources. (C) 2021 by the American Academy of Ophthalmology