The retina is the light-sensitive layer of tissue at the back of the inner eye that is considered part of the brain. It contains photoreceptor cells, which convert images into electrical signals and transport this information to the visual cortex through the optic nerve. Because the retina is densely innervated by nerve cells, it’s not at all surprising that it can be affected in many neurological diseases leading to vision problems.
The Dysautonomia Center team just published a new study describing the retina in multiple system atrophy (MSA) – a degenerative disease closely related with Parkinson disease. The team measured the retinal structure using optical coherence tomography (or OCT for short). The technique is safe, fast, entire non-invasive and scans the eye within minutes. It has better resolution than a standard magnetic resonance imaging (MRI). Despite the fact that patients with MSA don’t complain of visual problems, the study showed that they have a progressive loss of the cells and nerve fibers in the retina overtime.
Why is this important?
At the moment, the search is on to find ways to protect the nervous system and slow the disease progression by stopping the degeneration of nerves. Clinical trials in diseases like MSA require endpoints and finding good biological markers is important. Ideal biomarkers allow investigators to see early measurable signs that an intervention is working to stop a pathological process. They indicate to investigators that it is worthwhile continuing to test a particular drug. Objective biomarkers seem to be better as they provide hard measurements and are less subject to human bias, than for example a clinical rating scale. As lead author of the paper Carlos Mendoza points out, “Measuring retinal damage overtime appears to be a good way to track disease progression and could be useful as a biological endpoint in future clinical trials of MSA”.
Mendoza-Santiesteban CE, Palma JA, Martinez J, Norcliffe-Kaufmann L, Hedges TR, Kaufmann H. Progressive retinal structure abnormalities in multiple system atrophy. Mov Disord. 2015 Sep 11. doi: 10.1002/mds.26360.
The Center leads the Autonomic Disorders Consortium’s Natural History Study, an U54 grant awarded by the National Institutes for Health (NIH) and in partnership with the MSA Coalition. The natural history study is dedicated to mapping the clinical evolution of rare autonomic diseases.