Purpose: To measure the thickness of retinal peripapillary nerve fibers throughout the course of neuromyelitis optica (NMO).
Methods: This study was of a cross-sectional design, examining the thickness of the retinal peripapillary nerve fiber layer by optical coherence tomography, in patients with NMO (n = 15; 30 eyes), patients with multiple sclerosis (MS; n = 15; 30 eyes), and a control group (n = 23; 46 eyes). The thicknesses were acquired according to protocol with the fast RNFL (Retinal Nerve Fiber Layer) procedure. The study of visual function includes for each eye a determination of refraction, measurement of visual acuity, measurement of contrast vision, an analysis of color vision, and a frequency-doubling technology perimetry (FDTP). The main outcome measurements were the thickness of the retinal peripapillary nerve fibers, visual acuity, and scores of contrast vision.
Results: The average thickness of retinal peripapillary nerve fibers was respectively in the NMO, MS, and control group: 65.44 +/- 24.19, 83.85 +/- 24.12, and 106.24 +/- 12.46 microm (P = 0.01). The average thickness of retinal peripapillary nerve fibers correlated to visual acuity, the scores of contrast vision, the scores of FDTP, and the number of episodes per patient (r = -0.58, P = 0.03).
Conclusions: This is the first study to produce measurements of the thickness of retinal peripapillary nerve fibers during optic neuropathies of NMO. The optic neuropathies of NMO are also accompanied by an acute and chronic axonal loss, as clearly illustrated by the OCT.