In post-mortem eyes there is loss of cells in the retina in MS’ers.
- Post-mortem = after death
- Ganglion cells = specialised cells in the retina that integrate signals from the light sensing rods and cones
- Retina = layer at the back of the eye responsible for vision
The objective of this study was to ascertain whether patients with MS or the MS mimic euromyelitis optica (NMO) develop retinal neuronal layer damage following acute optic neuritis, and to characterise changes over time.
Retinal nerve fibre layer thickness, was measured using a technique called optical coherence tomography or OCT, which has been proposed as an outcome measure in studies of neuroprotective agents in MS.
OCT was performed serially in 20 participants during the acute phase of optic neuritis, and again 3 and 6 months later. OCT was also performed cross-sectionally in 98 MS’ers participants, 22 subjects with NMO and 72 healthy controls.
Results: Neuronal thinning was observed in the ganglion cell layer of eyes affected by acute optic neuritis 3 and 6 months after onset (P < 0.001). Ganglion cell layer thickness was lower in both participants with MS and participants with NMO, with and without a history of optic neuritis, when compared with healthy controls (P < 0.001) and correlated with visual function.
Of all patient groups investigated, those with NMO and a history of optic neuritis exhibited the greatest reduction in ganglion cell layer thickness.
Results from the longitudinal study demonstrate retinal neuronal layer thinning following acute optic neuritis, corroborating the hypothesis that axonal injury may cause neuronal pathology in MS.
Further, these data provide evidence of subclinical or asymptomatic disease activity, in both participants with MS and with NMO without a history of optic neuritis, a disease in which subclinical disease activity has not been widely appreciated.
The subsequent thinning of the retinal ganglion cell layer following acute optic neuritis, in the absence of evidence of baseline swelling, suggests the potential utility of quantitative OCT retinal layer segmentation to monitor neuroprotective effects of novel agents in therapeutic trials.
“This study is very useful and adds to the data supporting the use of OCT as an outcome measure for screening putative neuroprotective compounds in MS.”
“In fact we have a trial that is about to start to test phenytoin using OCT as the outcome measure. The trial design was developed as part of our PROMISE 2010 programme.”