Abstract
Purpose:
Longitudinal studies in multiple sclerosis (MS) show that visual function decreases as a function of time and is correlated with a thickening of the retinal nerve fiber layer (RNFL) measured by optical coherence tomography (OCT). We determined the outcome of visual acuity and RNFL thickness in Neuromyelitis optica (NMO) in the lack of clinical relapse.
Methods:
Patients underwent high and low-contrast visual acuity (2.5%, 1.25%), frequency doubling technology perimetry (FDTP) and OCT measurement of RNFL thickness at baseline and at least a year later.
Results:
Among 42 patients with ≥ 1 year follow-up, 15 (30 eyes) were diagnosed with NMO and 27 (53 eyes) with MS. While every assessment in NMO eyes did not show any decrease, MS eyes without history of optic neuritis (ON) showed a worsening of 1.25% low contrast visual acuity (-4,81; p=0,04) and FDT median deviation (-1.85; p=0.039). Furthermore, the whole MS eyes exhibited a significant loss of RNFL thickness (-4.56 μm; p<0.0001).
Conclusions:
While visual function in NMO patient remain stable, progressive RNFL thinning occurs as a function of time in patients with MS, even in the absence of ON, and is associated with clinically significant visual loss. These findings are consistent with sub-clinical axonal loss in MS and the absence of chronic inflammation in NMO. Consequently, NMO therapeutic strategies would have been limited to the acute relapses treatment and prevention. Neuroprotection would not have any effectiveness in this disease.
Keywords: 613 neuro-ophthalmology: optic nerve •
615 neuroprotection