LAUSR

&NA; Optic neuritis (ON) is an inflammatory condition that causes demyelination and thickening of the optic nerve leading to acute/subacute vision loss. It is frequently associated with other conditions like multiple sclerosis, but is often misdiagnosed, which can lead to a suboptimal prognosis. Ultrasound is rarely utilized to help make this diagnosis, even though it can easily detect a thickened retrobulbar optic nerve sheath diameter. We describe four cases in which ultrasonographic measurement of the optic nerve sheath diameter aided in the diagnosis of ON.