A New Technique to Assess Outcomes of Optic Neuritis

Optic neuritis (inflammation of the optic nerve, (ON)) causes visual loss and is a common early symptom of multiple sclerosis (MS). Patients with ON present to hospital early and identifying measurements of optic nerve function that can be used to predict clinical and neurological outcomes has become a major focus of research. Recently, an MRI technique known as diffusion tensor imaging (DTI) has been shown to identify differences in the earliest stages of optic neuritis. DTI can be used as a measure of the extent of nerve damage (Axonal loss) after ON.

To assess the effectiveness of early changes in DTI to predict long-term outcomes for people with ON, Van der Walt et al undertook a study of 40 people with ON and 10 healthy controls and assessed them within 48 hours of presenting to hospital, and again at 1,3, 6 and 12 months. Early changes in DTI as well as the initial visual loss, retinal swelling and loss of conduction of nerve signals were measured and compared against neurological, clinical and visual outcomes at 12 months after the episode of ON. DTI was markedly reduced in the affected optic nerve at 1 month after onset and this reduction corresponded to the extent of axon damage at 6 and 12 months after ON. In addition, a prolonged recovery time in DTI markers for up to 3 months was able to predict the degree of visual recovery at 12 months after ON. The investigators concluded that treatment to normalise the level of this marker could improve both axon survival and visual outcomes. Early reduction in DTI markers could be used to select patients with a likely poor recovery who would best benefit from new treatments targeting nerve protection in MS.

This summary comes from “Optic Nerve Diffusion Tensor Imaging after Acute Optic Neuritis Predicts Axonal and Visual Outcomes” by Van der Walt et al, published in PLOS One, December, 2013.