Acute "upside-down" visual inversion in a patient with multiple sclerosis.

Visual and oculomotor signs and symptoms are common and well defined in patients with multiple sclerosis. On the other hand, the phenomenon of "upside-down" reversal of vision is very rare and thus not well known. The physiopathology of this phenomenon also has not been well understood. Herein, we present a female patient with multiple sclerosis, who developed acute "upside-down" visual inversion, and discuss possible mechanisms of this rare phenomenon.