The retinal nerve fiber layer, neuroretinal rim area, and visual evoked potentials in MS.
In a prospective study of 57 patients with clinically definite, probable, or possible multiple sclerosis (MS), one-half of whom had a history of optic neuritis, retinal nerve fiber layer (RNFL) defects and the neuroretinal rim (NRR) area were quantitatively determined and compared with the visual evoked potential (VEP). There were abnormal VEP latencies in 63% of all patients (definite and probable = 68%, possible = 50%); local or diffuse RNFL defects in 54%, (definite and probable = 54%, possible = 50%); and an abnormally small NRR area in 30% (definite and probable = 32%, possible = 25%). Abnormalities in one or more of the VEP, RNFL, or NRR area occurred in 86% of all patients (definite and probable = 90%, possible = 75%), thus considerably increasing the yield of optic nerve abnormalities over that of the VEP alone. The predominance and extent of the diffuse RNFL defects, which are axonal abnormalities, suggest a more diffuse optic nerve pathology in MS than can be accounted for by a "plaque" pathology and indicate that extensive axonal loss commonly occurs in the optic nerves of MS.