The objective of this study was to evaluate the thickness of  the peripapillary retinal nerve fibre layer (RNFL), the paramacular volume, and the thickness of the different retinal layers in multiple sclerosis (MS) patient subgroups, using state-of-the-art optical coherence tomography.

Optical coherence tomography can be used to assess retinal degeneration in MS.

Thinning of the RNFL have been well characterized, but newer devices allow quantification of all retinal layers. Only scarce and in part conflicting data exists on different MS subtypes.

Using a Topcon DRI-OCT Triton Spectralis device, we performed paramacular volumetric retinal scans and circular peripapillary fibre-layer scans, manually segmenting different retinal layers into single horizontal foveal scans in 51 patients with definite MS (36 relapsing–remitting, 7 secondary progressive, 8 primary progressive), plus 30 age- and sex-matched controls.

Even without a history of optic neuritis, all MS eyes had significant thinning of the peripapillary RNFL, the retinal ganglion cell- and inner plexiform layer and the inner nuclear layer. In studying the different MS sub-groups, only in primary progressive MS was the peripapillary RNFL not significantly reduced.

Our findings indicate a preserved thickness of the peripapillary RNFL in primary progressive MS. Results in eyes without history of optic neuritis suggest possible subclinical episodes of optic neuritis or retrograde trans-synaptic degeneration of retinal ganglion cells and their axons.