Residents in the flipped classroom were assigned a pre-class video lecture prior to completing the flipped classroom in-class case-based activity in groups of 2-3 each.

Residents in the traditional classroom were assigned a pre-class reading assignment followed by a 44-minute lecture that was delivered in-person using PowerPoint.

In the Flipped Classroom, participants form groups of 2-3 and are instructed to work together through clinical cases of the in-class case based activity, committing to group answers to the clinical questions before advancing to the next case. At the end of class, the faculty instructor facilitated a short interactive group discussion.

Participants were asked to complete both a written (Likert-scale) survey in the classroom and an additional online survey (Catalyst WebQ, University of Washington, Seattle, WA) following the classroom session. These surveys asked residents to rate their preference for traditional vs. flipped classroom format, the effectiveness of preparation and classroom material, and the advantages and disadvantages of the flipped classroom format

Participants were assessed a total of three times for each course (esotropia and exotropia): once prior to starting the class (pre-test), once immediately after completing the class (post-test), and once three months later. All assessments consisted of 5 OKAP style questions created by fellowship trained ophthalmologists. These test questions were previously piloted. Residents were allotted 5 minutes to complete each test.