Multi-modal retinal scanning to measure retinal thickness and peripheral blood vessels in multiple sclerosis

Abstract

Our purpose was to investigate changes to the retina in multiple sclerosis (MS) using established and novel modes of retinal image acquisition and analysis. 72 participants with MS and 80 healthy volunteers underwent retinal scanning with optical coherence tomography (OCT) and ultra-widefield (UWF) scanning laser ophthalmoscopy (SLO), over a two-year period. Changes in retinal nerve fibre layer (RNFL) thickness, macular volume and retinal blood vessel diameter were measured and parameters were then tested for associations with MS. Measurements from OCT showed that individuals with MS had a thinner RNFL and reduced macular volume when compared to healthy volunteers. On UWF images, participants with MS had reduced arterial widths in the inferior nasal quadrant of both eyes and reduced venous widths in the inferior nasal quadrant of right eyes. Longitudinal analysis showed that participants with MS had an accelerated annual rate of RNFL thinning in several regions of the retina. In conclusion, the assessment of OCT showed thinning of the RNFL and macula in concordance with previous reports on MS, while analysis of blood vessels in the retinal periphery from UWF-SLO images revealed novel changes.

Figure 1

UWF imaging and analysis. Left: Example of the 8 vessels selected for analysis in a participant (2 from each quadrant). Veins are blue and arteries red, with the nodes (i.e., crossings, bifurcations, start and end points) plotted as green crosses. Right: The red channel of the same image separated into quadrants (green lines), with 6.5 to 8.5 optic disc radii marked with the red concentric circles.