Abstract
Purpose:
To describe pattern-reversal visual evoked potentials (VEP) in neuromyelitis optica (NMO) and its correlation to visual-field examination (VF) and retinal nerve fiber layer thickness (RNFLt).
Methods:
A total of 25 patients with NMO were included (4 males, 41.7 ± 14 years), of which 17 patients had experienced bilateral optic neuritis (ON) and 7 patients had experienced unilateral ON (ON; n=43). Evaluation included best-corrected visual acuity (BCVA), VEP (according to the ISCEV standard), 24-2 VF and optical coherence tomography (OCT) for RNFLt measurement.
Results:
In ON eyes, BCVA ranged from 0.0 logMAR (20/20) to no light perception. A significant correlation was observed between BCVA and RNFLt (r=-0.58; P<0.001). All 7 eyes without ON history showed normal VEPs. In 37% of the ON eyes, VEP could not be performed due to poor vision and the absence of fixation. Of the remaining ON eyes, 28% showed normal VEPs, 19% exhibited delayed latency (>120 ms), and 19% exhibited reduced (<5 µV) or absent amplitude. A significant correlation between VEP amplitude and RNFLt was observed (r=0.607; P<0.001), but no correlation was found between VEP latency and RNFLt (r=-0.177; P=0.340). Significant correlations were also observed between visual field mean deviation (MD) and RNFLt (r=-0.615; P<0.001), VEP amplitude and visual field MD (r=0.286; P=0.125), and VEP amplitude and BCVA (r=-0.5720; P<0.001).
Conclusions:
No typical VEP pattern for amplitude or latency was observed in ON eyes in NMO. Visual function impairment correlates to an RNFLt decrease in NMO ON, as determined by visual acuity, visual field mean sensitivity and VEP amplitude.
Keywords: 613 neuro-ophthalmology: optic nerve •
507 electrophysiology: clinical •
610 nerve fiber layer