BLURRING of vision is a common complaint of patients with multiple sclerosis and is usually attributed to the pallor of the optic disks, or "bitemporal pallor," frequently observed in this condition. In studying patients with acquired nystagmus on direct forward gaze (fixation nystagmus), we found that they all complained of blurred vision. A more detailed description of this symptom disclosed that the visual disturbance was actually oscillopsia, a visual sensation in which objects appear to be moving rapidly from side to side or up and down (oscillating).
It has been observed1 that intravenous injections of barbiturates temporarily abolish fixation nystagmus and the associated sensation of oscillopsia. The present investigation consists of the intravenous administration of barbiturates to patients with and without evidence of pallor of the optic disks in the presence of nystagmus on direct forward gaze. When the nystagmus has been abolished, it is possible to evaluate the