Objective:

To determine differences in nerve fiber layer (NFL) thickness by Optical Coherence Tomography (OCT) in patients with neuromyelitis optica (NMO) and Multiple Sclerosis (MS)

Methods:

Case series study in adult patients diagnosed with MS and NMO.

Results:

The estimated median and interquartile range (IQR) for nerve fiber layer thickness in healthy subjects was 110 IQR (16) µm, in patients with MS was 94 (21) µm and in patients with NMO was 76.5 (61) µm. The differences between healthy and sick subjects were estimated, finding that the NFL thickness was significantly lower in absolute data: Δ = 16 µm for healthy-MS and Δ = 33.5 µm for healthy-NMO. Regarding the quadrants of retinal nerve fiber layer, it was found that the lower and upper quadrants have a greater loss of nerve fibers in both diseases.

Conclusions:

Our study supports evidence related to the involvement of ganglion cell layer and NFL observed in patients with MS and NMO. This study confirms what has been reported in other studies, that NFL thickness is a measure that can help diagnose the compromise and severity of optic nerve involvement in these two demyelinating diseases, with patterns that help to differentiate between NMO and EM.