CONCLUSION: The test is simple and sensitive enough to separate normal subjects from patients suffering from a vestibular loss. There was also a good correlation between the objective results and the subjective complaint of oscillopsia. OBJECTIVES: Oscillopsia (i.e. blurred vision while walking) is often reported by patients suffering from vestibular loss. We developed a test to quantify oscillopsia. METHODS: Visual acuity was determined in 16 normal subjects and in 8 patients suffering from a bilateral vestibular loss, at rest and while walking at increasing speed on a treadmill. Snellen optotypes were randomly projected on a screen and the visual acuity was determined with an adaptative staircase algorithm. RESULTS: In normal subjects, the visual acuity did not decrease markedly during walking, but decreased significantly in patients with a vestibular loss.