Axonal loss is an important cause of irreversible disability in multiple sclerosis. Whilst recovery of neurological function due to restoration of neuronal conduction is usual after multiple sclerosis relapse, some relapses are followed by fixed disability. Quantitative measures of axons in the retina, and in their continuation in the optic nerve allow measurement of the effect upon axons of a prototypical multiple sclerosis relapse, optic neuritis. Using optical coherence tomography, axonal and neuronal loss were observable in the retina of patients with progressive multiple sclerosis, even when they were clinically unaf- fected by optic neuritis. With follow-up, these changes were found to be stable. After optic neuritis, 99% of retinal nerve fibre layer thinning was detectable by 4.75 months, and 99% of macular volume loss was detectable by 11 months. The earliest time to detect retinal nerve fibre layer thinning was 1.64 months, and the earliest time to detect macular volume loss was 0.99 months. Sample sizes for clinical trials generated for trials of neuro-protective agents, using multiple sclerosis thickness as an endpoint, showed that 35 subjects per arm of a randomised trial would be needed to detect an 50% effect, with 80% power. Early measures of colour vision and visual evoked potential delay were strongly related to the eventual degree of axonal loss. Comparisons of two methods of measuring multiple sclerosis thinning after optic neuritis suggested that optical coherence tomography would be superior to scanning laser polarimetry. Comparisons of optic nerve mean area and multiple sclerosis thickness showed that whilst initial swelling was similar, the degree of subsequent atrophy was less in the optic nerve. Measures of axonal loss in the retina will be an important method for assessing the efficacy of therapies that propose to prevent axonal loss in multiple sclerosis and optic neuritis.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:626097 |
| Date | January 2013 |
| Creators | Henderson, A. P. D. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1386992/ |
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