Fluorescein fundus photography is of value in the detection of early papilloedema (David, Heyman, and Hart, 1963; Miller, Saunders, and Ffytche, 1965). We have applied this technique to the serial study of patients with acute retrobulbar neuritis. This disorder is usually unilateral and the unaffected eye could be used as a control. Also, since papilloedema is not present at the onset of sympto...