The Institute of Medicine estimates that 5% of adults experience a diagnostic error in outpatient care and that diagnostic errors are responsible for 17% of inpatient adverse events.¹ Ophthalmology is not exempt from this problem. An analysis of patients referred to neuro-ophthalmologists found that the referral diagnosis was incorrect 49% of the time, and 26% of patients experienced harm as a result.² In a study of referrals to an ophthalmic emergency department, the misdiagnosis rate was 25%.³ Recognizing this problem, the American Academy of Ophthalmology and the American Board of Ophthalmology have begun discussing how to build a culture of safety in ophthalmology.⁴ So, why are these high rates of ophthalmic diagnostic error occurring?