Electrophysiology and perimetry in acute retrobulbar neuritis

Eighteen patients with acute retrobulbar neuritis were examined by visual field analysis and electroophthalmological recordings. The visual fields were measured to 30 degrees with the automatic perimeter Octopus 201. The pattern-evoked cortical potential showed an increased P-100 latency followed by a decrease in 12 patients during the first two weeks of the disease. This latency change cannot be explained by remyelinization. Teh positive component of the pattern ERG (P-50) was reduced in all acutely affected eyes in comparison with the fellow eye. During recovery, the amplitude of the positive PERG component increased to normal, but remained slightly reduced in comparison with the response from the fellow eyes. Thirteen patients out of 18 were clinically and electrophysiologically diagnosed as having unilateral retrobulbar neuritis. However, static perimetry showed paracentral scotomas in the fellow eye in 5 cases. Recovery of the severely affected eye was accompanied by complete normalization of the visual field in the fellow eye. Thus static perimetry seems to be a more sensitive test than even the visual evoked potentials for detecting lesions in the visual pathway.