A simple psychophysical technique provides early diagnosis in optic neuritis.

Patients with optic neuritis describe image fading which is particularly evident at bright light levels. The effect is dependent on adaptation level, and high adaptation levels serve as a provocative test. Kinetic and static perimetry and interferometric acuity tests repeated in time reveal this loss in sensitivity. The latter test, using a large field and a high luminance level, is particularly sensitive to both the residua of pathology and very early phases of disease, often before subjective manifestations of anomalies are present. These effects are large in patients with demyelinating diseases. Here, we show that such changes may be revealed in optic neuritis due to other causes as well. Note, the same form of response may be detected in more central lesions, but usually in more circumscribed areas of field.