Abstract
Purpose :
Multiple Sclerosis (MS) is a demyelinating disease of the central nervous system that can cause myelitis and other pathological signs and symptoms, including severe optic neuritis (ON). The results of previous studies have suggested that early structural changes of retina, such as peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer (GCL), and outer nuclear layer (ONL) were present in patients with MS, which occurs even in the absence of ON. The purpose of this study was to determine the retinal sensitivity and retinal structure by spectral-domain optical coherence tomography (SD-OCT) in patients with MS who have no history of ON compared to those of healthy control (HC) groups.
Methods :
Twenty-four eyes of 12 patients with MS who had no history of ON were studied, the MS group. We determined the retinal sensitivity of the central 10° (37 points) by macular integrity assessment (MAIA). The retinal sensitivity was determined for a 37 stimulus grid covering 10° of the central retina. 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 pRNFL, GCL, and ONL from the OCT images. Thirty-one eyes of 16 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=0.13), age (P=0.52), and refractive error (P=0.16) between the MS and HC groups. The retinal sensitivity of the central 10° was significantly lower in the MS group compared to the HC group (MS, 27.4±1.79 dB; HC, 29.7±0.84 dB, P<0.001, Mann-Whitney U-test). The pRNFL thickness (MS, 94.5±15.8 μm; HC, 104.7±7.8 μm), GCL thickness (MS, 88.3±11.0 μm; HC, 98.5±5.1 μm), and ONL thickness (MS, 77.4±9.1 μm; HC, 95.6±15.4 μm) were significantly different between the two groups (P<0.05, P<0.001, and P<0.001 respectively, Mann-Whitney U-test).
Conclusions :
These results indicate that the visual function is impaired even before the development of ON in MS patients, and also that the functional impairments precede the structural impairments. We suggest that the cause of the thinning of GCL, pRNFL, and ONL thickness may be due to a transsynaptic retrograde degeneration, consequently resulting to subclinical optic neuritis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.