Researchers in the United Kingdom have reported that decreased cone densities are associated with multiple sclerosis (MS).
This is the first study to show lower photoreceptor outer densities and spacing in patients with MS, suggesting that retinal imaging “has the potential to become a sensitive marker for MS”.1
“Whether the observed changes in this cross-sectional study can be translated to a larger and more ethnically diverse population remains to be seen,” the study authors said.
Gemma McIlwaine, from Queen’s University Belfast in Northern Ireland, and colleagues conducted a single-centre, cross-sectional study to identify possible changes in the outer retina in 16 patients with MS and 25 controls without diagnosed MS.
They evaluated spectral-domain optical coherence tomography (OCT) scans of the macula and a circular scan around the optic nerve head (ONH). They captured adaptive optics (AO) images at 0° (centered on the foveola), 2°, 4°, and 6° temporal to the fovea.
The thickness of the different retinal layers in the macula and around the ONH were calculated using the inbuilt software of the OCT.
Main Outcomes
Changes in the cone photoreceptors were evaluated by calculating cone density and spacing by the inbuilt AO automatic segmentation algorithm with manual correction, the study authors said.
The results were then compared in patients with and without optic neuritis and controls.
The investigators observed significant thinning of the inner retina and thickening of the outer retina in eyes with a history of optic neuritis. No changes were seen in the retinal layers in eyes without optic neuritis.
Regional differences were seen in the peripapillary retinal nerve fibre layer. Analysing AO images showed a significantly lower cone outer-segment density at all eccentricities in all patients compared with control eyes, independent of the presence or absence of optic neuritis, the authors said.
References
1. McIIwaine, G., Csincsik, L., Coey, R., et al., Reduced cone density is associated with multiple sclerosis. Ophthalmol Sci. Published online: 12 April 2023: doi.org/10.1016/j.xops.2023.100308.
