Abstract
Purpose:
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory autoimmune disease that can cause severe optic neuritis (ON) and myelitis. The results of previous studies have suggested that early structural changes of retina were present in patients with multiple sclerosis (MS) who have no history of ON. However, there has been very few reports of functional or structural changes in patients with NMOSD who have no history of ON. The purpose of this study was to determine the retinal sensitivity by microperimetry and retinal structure by spectral-domain optical coherence tomography (SD-OCT) in patients with NMOSD who have no history of ON. In addition, we compared the early functional and structural changes of the retina of patients with NMOSD to that of healthy controls.
Methods:
Twelve eyes of 6 patients with NMOSD who had no history of ON were studied, the NMOSD group. We determined the retinal sensitivity of the central 100 (37 points) and central 20 (13 points) by macular integrity assessment (MAIA). We also measured the best-corrected visual acuity (BCVA) expressed in logarithm of minimum angle of resolution (logMAR) units and retinal structure by SD-OCT. We quantified the mean thickness of the retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) from the OCT images. Twenty-five eyes of 13 volunteers who had no high myopia, glaucoma, or other macular disorders were included in the HC groups.
Results:
There was no significant difference in the BCVA (P=0.168), age (P=0.321), and refractive error (P=0.549) between the NMOSD and HC groups. The retinal sensitivity of the central 100 (NMOSD, 27.65±1.75 dB; HC, 29.12±0.85 dB) and 2 degrees (NMOSD, 27.68±1.96 dB; HC,29.41±1.12 dB) were significantly lower in the NMOSD group (P=0.015 and P=0.015 respectively, Mann-Whitney U-test). The RNFL thickness (NMOSD, 109.5±14.6 μm; HC, 107.2±7.4 μm), and GCL thickness(NMOSD, 94.7±12.0 μm; HC, 97.5±5.2 μm) were not significantly different between the two groups (P=0.527, P=0.557 respectively, Mann-Whitney U-test).
Conclusions:
These results indicate that the retinal sensitivity is impaired even before the development of ON in NMOSD patients, and also that the functional impairments precede the structural impairments. Although further investigations are needed, microperimetry appears useful to determine subclinical change of retina in eyes with NMOSD