Ocular dominance is a term that often is thrown around when thinking about cataract and laser surgery, especially with regards to monovision. Despite this, testing of ocular dominance is often poorly understood and performed. This can lead to post-operative headaches - literally! In this episode of Ophthalmology Against The Rule, we discuss the strengths and weaknesses of different tests of ocular dominance and what they may imply for decision making in the clinic.