Various stages of optic neuritis assessed by subjective brightness of flicker.

In the Aulhorn flicker test, the subjective brightness of a steady field is matched to that of a flickering field at 50 to 0 Hz. The test gives pathologic values only for active optic neuritis (ON) and gives normal results for normal eyes and eyes with subsided ON and other diagnoses, with a specificity of 98% and a sensitivity of 85.5%. Characteristic variations of the curves of subjective brightness during the course of ON allow a subtle assessment of five different disease stages, and there is a clear distinction between various disease patterns, ie, acute, chronic, recurrent, diminishing, and subsided ON. This distinction is impossible on the basis of visual evoked potentials. The test can be done easily and quickly without major technical equipment, even in an ophthalmologist's office.