Ocular Coherence Tomography (OCT)
University of Wisconsin, Madison
Dr. Ian Duncan
1 year grant, $75,000
The use of optical coherence tomography (OCT) in measuring nerve fiber loss in Multiple Sclerosis (MS)
In recent years it has become increasingly apparent that loss of nerve fibers (axons) is the likely factor that results in the progression of neurologic symptoms in MS patients to secondary progressive disease. At this point in the disease, no known treatments have any beneficial effect. There is therefore an urgent need to devise neuroprotective strategies to prevent axon loss. Critical to such strategies is the ability to image axons in the live patient, or develop surrogate markers that accomplish this. In this regard, OCT has become an important measure of loss of axons in the optic nerve, a frequent target of inflammation (optic neuritis) in MS. OCT can be used to image the retina and in particular measure the retinal nerve fiber layer (RNFL). It is proposed that in MS patients, loss of axons in the optic nerve results in thinning of the RNFL; hence this may be a surrogate marker of axon loss. However, there is no direct proof of this and confirmation is needed before thinning of the RNFL in MS patients can be unequivocally confirmed as a correlate of axon loss.
Through the generous support of MS Hope for a Cure, we purchased an Optical Coherence Tomograph for use in an experimental animal model. In this model, known as experimental autoimmune encephalomyelitis (EAE), there is severe axon loss in the optic nerve in our animal model. We will therefore measure the RNFL before and after the onset of disease to determine whether this measure truly represents axon loss in the optic nerve. We will then test a putative neuroprotective drug to see whether it can prevent axon loss and hence stop RNFL atrophy, thus confirming the usefulness of this drug in MS treatment, and OCT as a measure of loss of axons.