BACKGROUND: Although migraine headache has received substantial attention in the scientific literature, migraine aura without headache (MAWOH) has not been investigated frequently. A general population survey study estimated the lifetime prevalence of MAWOH to be 1% in males and 3% in females. Anecdotal evidence has suggested that MAWOH is encountered by primary eye care practitioners more frequently than these rates suggest. This study is the first investigation of this condition in a primary eye care population. METHODS: A written questionnaire was used to survey 1,000 patients, ages 18 years and older, presenting for a comprehensive eye examination in the Primary Care Optometry Service of the School of Optometry, University of Alabama at Birmingham. Cases were identified by the presence of visual sensations consistent with MAWOH. RESULTS: Of the primary eye care population surveyed, 6.5% reported experiencing visual sensations consistent with MAWOH. The prevalence in males was 2.9% and in females, 8.6%. A multivariate analysis revealed that female gender (odds ratio [OR] = 2.3), history of migraine headaches (OR = 3.2), and history of childhood motion sickness (OR = 2.7) were significantly related to MAWOH. CONCLUSIONS: The prevalence of MAWOH is higher in an adult primary eye care population than previously reported in a general population study.